Series comparison

-[Qemu-devel] [PULL v2 00/24] Block patches
+[Qemu-devel] [PULL v2 00/10] Block patches
-The following changes since commit 56f9e46b841c7be478ca038d8d4085d776ab4b0d:
+The following changes since commit 19b599f7664b2ebfd0f405fb79c14dd241557452:
-  Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2017-02-20' into staging (2017-02-20 17:42:47 +0000)
+  Merge remote-tracking branch 'remotes/armbru/tags/pull-error-2018-08-27-v2' into staging (2018-08-27 16:44:20 +0100)
-are available in the git repository at:
+are available in the Git repository at:
-  git://github.com/stefanha/qemu.git tags/block-pull-request
+  https://git.xanclic.moe/XanClic/qemu.git tags/pull-block-2018-08-31-v2
-for you to fetch changes up to a7b91d35bab97a2d3e779d0c64c9b837b52a6cf7:
+for you to fetch changes up to e21a1c9831fc80ae3f3c1affdfa43350035d8588:
-  coroutine-lock: make CoRwlock thread-safe and fair (2017-02-21 11:39:40 +0000)
+  jobs: remove job_defer_to_main_loop (2018-08-31 16:28:33 +0200)
 ----------------------------------------------------------------
-Pull request
+Block patches:
+- (Block) job exit refactoring, part 1
-v2:
+  (removing job_defer_to_main_loop())
- * Rebased to resolve scsi conflicts
+- test-bdrv-drain leak fix
 ----------------------------------------------------------------
+John Snow (9):
+  jobs: change start callback to run callback
+  jobs: canonize Error object
+  jobs: add exit shim
+  block/commit: utilize job_exit shim
+  block/mirror: utilize job_exit shim
+  jobs: utilize job_exit shim
+  block/backup: make function variables consistently named
+  jobs: remove ret argument to job_completed; privatize it
+  jobs: remove job_defer_to_main_loop
-Paolo Bonzini (24):
+Marc-André Lureau (1):
-  block: move AioContext, QEMUTimer, main-loop to libqemuutil
+  tests: fix bdrv-drain leak
   aio: introduce aio_co_schedule and aio_co_wake
   block-backend: allow blk_prw from coroutine context
   test-thread-pool: use generic AioContext infrastructure
   io: add methods to set I/O handlers on AioContext
   io: make qio_channel_yield aware of AioContexts
   nbd: convert to use qio_channel_yield
   coroutine-lock: reschedule coroutine on the AioContext it was running
     on
   blkdebug: reschedule coroutine on the AioContext it is running on
   qed: introduce qed_aio_start_io and qed_aio_next_io_cb
   aio: push aio_context_acquire/release down to dispatching
   block: explicitly acquire aiocontext in timers that need it
   block: explicitly acquire aiocontext in callbacks that need it
   block: explicitly acquire aiocontext in bottom halves that need it
   block: explicitly acquire aiocontext in aio callbacks that need it
   aio-posix: partially inline aio_dispatch into aio_poll
   async: remove unnecessary inc/dec pairs
   block: document fields protected by AioContext lock
   coroutine-lock: make CoMutex thread-safe
   coroutine-lock: add limited spinning to CoMutex
   test-aio-multithread: add performance comparison with thread-based
     mutexes
   coroutine-lock: place CoMutex before CoQueue in header
   coroutine-lock: add mutex argument to CoQueue APIs
   coroutine-lock: make CoRwlock thread-safe and fair
- Makefile.objs                       |   4 -
+ include/qemu/job.h        | 70 ++++++++++++++++-----------------
- stubs/Makefile.objs                 |   1 +
+ block/backup.c            | 81 ++++++++++++++++-----------------------
- tests/Makefile.include              |  19 +-
+ block/commit.c            | 29 +++++---------
- util/Makefile.objs                  |   6 +-
+ block/create.c            | 19 +++------
- block/nbd-client.h                  |   2 +-
+ block/mirror.c            | 39 ++++++++-----------
- block/qed.h                         |   3 +
+ block/stream.c            | 29 ++++++--------
- include/block/aio.h                 |  38 ++-
+ job-qmp.c                 |  5 ++-
- include/block/block_int.h           |  64 +++--
+ job.c                     | 73 ++++++++++++-----------------------
- include/io/channel.h                |  72 +++++-
+ tests/test-bdrv-drain.c   | 14 +++----
- include/qemu/coroutine.h            |  84 ++++---
+ tests/test-blockjob-txn.c | 25 +++++-------
- include/qemu/coroutine_int.h        |  11 +-
+ tests/test-blockjob.c     | 17 ++++----
- include/sysemu/block-backend.h      |  14 +-
+ trace-events              |  2 +-
- tests/iothread.h                    |  25 ++
+files changed, 161 insertions(+), 242 deletions(-)
  block/backup.c                      |   2 +-
  block/blkdebug.c                    |   9 +-
  block/blkreplay.c                   |   2 +-
  block/block-backend.c               |  13 +-
  block/curl.c                        |  44 +++-
  block/gluster.c                     |   9 +-
  block/io.c                          |  42 +---
  block/iscsi.c                       |  15 +-
  block/linux-aio.c                   |  10 +-
  block/mirror.c                      |  12 +-
  block/nbd-client.c                  | 119 +++++----
  block/nfs.c                         |   9 +-
  block/qcow2-cluster.c               |   4 +-
  block/qed-cluster.c                 |   2 +
  block/qed-table.c                   |  12 +-
  block/qed.c                         |  58 +++--
  block/sheepdog.c                    |  31 +--
  block/ssh.c                         |  29 +--
  block/throttle-groups.c             |   4 +-
  block/win32-aio.c                   |   9 +-
  dma-helpers.c                       |   2 +
  hw/9pfs/9p.c                        |   2 +-
  hw/block/virtio-blk.c               |  19 +-
  hw/scsi/scsi-bus.c                  |   2 +
  hw/scsi/scsi-disk.c                 |  15 ++
  hw/scsi/scsi-generic.c              |  20 +-
  hw/scsi/virtio-scsi.c               |   7 +
  io/channel-command.c                |  13 +
  io/channel-file.c                   |  11 +
  io/channel-socket.c                 |  16 +-
  io/channel-tls.c                    |  12 +
  io/channel-watch.c                  |   6 +
  io/channel.c                        |  97 ++++++--
  nbd/client.c                        |   2 +-
  nbd/common.c                        |   9 +-
  nbd/server.c                        |  94 +++-----
  stubs/linux-aio.c                   |  32 +++
  stubs/set-fd-handler.c              |  11 -
  tests/iothread.c                    |  91 +++++++
  tests/test-aio-multithread.c        | 463 ++++++++++++++++++++++++++++++++++++
  tests/test-thread-pool.c            |  12 +-
  aio-posix.c => util/aio-posix.c     |  62 ++---
  aio-win32.c => util/aio-win32.c     |  30 +--
  util/aiocb.c                        |  55 +++++
  async.c => util/async.c             |  84 ++++++-
  iohandler.c => util/iohandler.c     |   0
  main-loop.c => util/main-loop.c     |   0
  util/qemu-coroutine-lock.c          | 254 ++++++++++++++++++--
  util/qemu-coroutine-sleep.c         |   2 +-
  util/qemu-coroutine.c               |   8 +
  qemu-timer.c => util/qemu-timer.c   |   0
  thread-pool.c => util/thread-pool.c |   8 +-
  trace-events                        |  11 -
  util/trace-events                   |  17 +-
 files changed, 1712 insertions(+), 533 deletions(-)
  create mode 100644 tests/iothread.h
  create mode 100644 stubs/linux-aio.c
  create mode 100644 tests/iothread.c
  create mode 100644 tests/test-aio-multithread.c
  rename aio-posix.c => util/aio-posix.c (94%)
  rename aio-win32.c => util/aio-win32.c (95%)
  create mode 100644 util/aiocb.c
  rename async.c => util/async.c (82%)
  rename iohandler.c => util/iohandler.c (100%)
  rename main-loop.c => util/main-loop.c (100%)
  rename qemu-timer.c => util/qemu-timer.c (100%)
  rename thread-pool.c => util/thread-pool.c (97%)
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 01/24] block: move AioContext, QEMUTimer, main-loop to libqemuutil
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-AioContext is fairly self contained, the only dependency is QEMUTimer but
-that in turn doesn't need anything else.  So move them out of block-obj-y
-to avoid introducing a dependency from io/ to block-obj-y.
-main-loop and its dependency iohandler also need to be moved, because
-later in this series io/ will call iohandler_get_aio_context.
-[Changed copyright "the QEMU team" to "other QEMU contributors" as
-suggested by Daniel Berrange and agreed by Paolo.
---Stefan]
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213135235.12274-2-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- Makefile.objs                       |  4 ---
- stubs/Makefile.objs                 |  1 +
- tests/Makefile.include              | 11 ++++----
- util/Makefile.objs                  |  6 +++-
- block/io.c                          | 29 -------------------
- stubs/linux-aio.c                   | 32 +++++++++++++++++++++
- stubs/set-fd-handler.c              | 11 --------
- aio-posix.c => util/aio-posix.c     |  2 +-
- aio-win32.c => util/aio-win32.c     |  0
- util/aiocb.c                        | 55 +++++++++++++++++++++++++++++++++++++
- async.c => util/async.c             |  3 +-
- iohandler.c => util/iohandler.c     |  0
- main-loop.c => util/main-loop.c     |  0
- qemu-timer.c => util/qemu-timer.c   |  0
- thread-pool.c => util/thread-pool.c |  2 +-
- trace-events                        | 11 --------
- util/trace-events                   | 11 ++++++++
-files changed, 114 insertions(+), 64 deletions(-)
- create mode 100644 stubs/linux-aio.c
- rename aio-posix.c => util/aio-posix.c (99%)
- rename aio-win32.c => util/aio-win32.c (100%)
- create mode 100644 util/aiocb.c
- rename async.c => util/async.c (99%)
- rename iohandler.c => util/iohandler.c (100%)
- rename main-loop.c => util/main-loop.c (100%)
- rename qemu-timer.c => util/qemu-timer.c (100%)
- rename thread-pool.c => util/thread-pool.c (99%)
-diff --git a/Makefile.objs b/Makefile.objs
-index XXXXXXX..XXXXXXX 100644
---- a/Makefile.objs
-+++ b/Makefile.objs
-@@ -XXX,XX +XXX,XX @@ chardev-obj-y = chardev/
- #######################################################################
- # block-obj-y is code used by both qemu system emulation and qemu-img
--block-obj-y = async.o thread-pool.o
- block-obj-y += nbd/
- block-obj-y += block.o blockjob.o
--block-obj-y += main-loop.o iohandler.o qemu-timer.o
--block-obj-$(CONFIG_POSIX) += aio-posix.o
--block-obj-$(CONFIG_WIN32) += aio-win32.o
- block-obj-y += block/
- block-obj-y += qemu-io-cmds.o
- block-obj-$(CONFIG_REPLICATION) += replication.o
-diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
-index XXXXXXX..XXXXXXX 100644
---- a/stubs/Makefile.objs
-+++ b/stubs/Makefile.objs
-@@ -XXX,XX +XXX,XX @@ stub-obj-y += get-vm-name.o
- stub-obj-y += iothread.o
- stub-obj-y += iothread-lock.o
- stub-obj-y += is-daemonized.o
-+stub-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
- stub-obj-y += machine-init-done.o
- stub-obj-y += migr-blocker.o
- stub-obj-y += monitor.o
-diff --git a/tests/Makefile.include b/tests/Makefile.include
-index XXXXXXX..XXXXXXX 100644
---- a/tests/Makefile.include
-+++ b/tests/Makefile.include
-@@ -XXX,XX +XXX,XX @@ check-unit-y += tests/test-visitor-serialization$(EXESUF)
- check-unit-y += tests/test-iov$(EXESUF)
- gcov-files-test-iov-y = util/iov.c
- check-unit-y += tests/test-aio$(EXESUF)
-+gcov-files-test-aio-y = util/async.c util/qemu-timer.o
-+gcov-files-test-aio-$(CONFIG_WIN32) += util/aio-win32.c
-+gcov-files-test-aio-$(CONFIG_POSIX) += util/aio-posix.c
- check-unit-y += tests/test-throttle$(EXESUF)
- gcov-files-test-aio-$(CONFIG_WIN32) = aio-win32.c
- gcov-files-test-aio-$(CONFIG_POSIX) = aio-posix.c
-@@ -XXX,XX +XXX,XX @@ tests/check-qjson$(EXESUF): tests/check-qjson.o $(test-util-obj-y)
- tests/check-qom-interface$(EXESUF): tests/check-qom-interface.o $(test-qom-obj-y)
- tests/check-qom-proplist$(EXESUF): tests/check-qom-proplist.o $(test-qom-obj-y)
--tests/test-char$(EXESUF): tests/test-char.o qemu-timer.o \
--    $(test-util-obj-y) $(qtest-obj-y) $(test-block-obj-y) $(chardev-obj-y)
-+tests/test-char$(EXESUF): tests/test-char.o $(test-util-obj-y) $(qtest-obj-y) $(test-io-obj-y) $(chardev-obj-y)
- tests/test-coroutine$(EXESUF): tests/test-coroutine.o $(test-block-obj-y)
- tests/test-aio$(EXESUF): tests/test-aio.o $(test-block-obj-y)
- tests/test-throttle$(EXESUF): tests/test-throttle.o $(test-block-obj-y)
-@@ -XXX,XX +XXX,XX @@ tests/test-vmstate$(EXESUF): tests/test-vmstate.o \
-     migration/vmstate.o migration/qemu-file.o \
-         migration/qemu-file-channel.o migration/qjson.o \
-     $(test-io-obj-y)
--tests/test-timed-average$(EXESUF): tests/test-timed-average.o qemu-timer.o \
--    $(test-util-obj-y)
-+tests/test-timed-average$(EXESUF): tests/test-timed-average.o $(test-util-obj-y)
- tests/test-base64$(EXESUF): tests/test-base64.o \
-     libqemuutil.a libqemustub.a
- tests/ptimer-test$(EXESUF): tests/ptimer-test.o tests/ptimer-test-stubs.o hw/core/ptimer.o libqemustub.a
-@@ -XXX,XX +XXX,XX @@ tests/usb-hcd-ehci-test$(EXESUF): tests/usb-hcd-ehci-test.o $(libqos-usb-obj-y)
- tests/usb-hcd-xhci-test$(EXESUF): tests/usb-hcd-xhci-test.o $(libqos-usb-obj-y)
- tests/pc-cpu-test$(EXESUF): tests/pc-cpu-test.o
- tests/postcopy-test$(EXESUF): tests/postcopy-test.o
--tests/vhost-user-test$(EXESUF): tests/vhost-user-test.o qemu-timer.o \
-+tests/vhost-user-test$(EXESUF): tests/vhost-user-test.o $(test-util-obj-y) \
-     $(qtest-obj-y) $(test-io-obj-y) $(libqos-virtio-obj-y) $(libqos-pc-obj-y) \
-     $(chardev-obj-y)
- tests/qemu-iotests/socket_scm_helper$(EXESUF): tests/qemu-iotests/socket_scm_helper.o
-diff --git a/util/Makefile.objs b/util/Makefile.objs
-index XXXXXXX..XXXXXXX 100644
---- a/util/Makefile.objs
-+++ b/util/Makefile.objs
-@@ -XXX,XX +XXX,XX @@
- util-obj-y = osdep.o cutils.o unicode.o qemu-timer-common.o
- util-obj-y += bufferiszero.o
- util-obj-y += lockcnt.o
-+util-obj-y += aiocb.o async.o thread-pool.o qemu-timer.o
-+util-obj-y += main-loop.o iohandler.o
-+util-obj-$(CONFIG_POSIX) += aio-posix.o
- util-obj-$(CONFIG_POSIX) += compatfd.o
- util-obj-$(CONFIG_POSIX) += event_notifier-posix.o
- util-obj-$(CONFIG_POSIX) += mmap-alloc.o
- util-obj-$(CONFIG_POSIX) += oslib-posix.o
- util-obj-$(CONFIG_POSIX) += qemu-openpty.o
- util-obj-$(CONFIG_POSIX) += qemu-thread-posix.o
--util-obj-$(CONFIG_WIN32) += event_notifier-win32.o
- util-obj-$(CONFIG_POSIX) += memfd.o
-+util-obj-$(CONFIG_WIN32) += aio-win32.o
-+util-obj-$(CONFIG_WIN32) += event_notifier-win32.o
- util-obj-$(CONFIG_WIN32) += oslib-win32.o
- util-obj-$(CONFIG_WIN32) += qemu-thread-win32.o
- util-obj-y += envlist.o path.o module.o
-diff --git a/block/io.c b/block/io.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/io.c
-+++ b/block/io.c
-@@ -XXX,XX +XXX,XX @@ BlockAIOCB *bdrv_aio_flush(BlockDriverState *bs,
-     return &acb->common;
- }
--void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
--                   BlockCompletionFunc *cb, void *opaque)
--{
--    BlockAIOCB *acb;
--
--    acb = g_malloc(aiocb_info->aiocb_size);
--    acb->aiocb_info = aiocb_info;
--    acb->bs = bs;
--    acb->cb = cb;
--    acb->opaque = opaque;
--    acb->refcnt = 1;
--    return acb;
--}
--
--void qemu_aio_ref(void *p)
--{
--    BlockAIOCB *acb = p;
--    acb->refcnt++;
--}
--
--void qemu_aio_unref(void *p)
--{
--    BlockAIOCB *acb = p;
--    assert(acb->refcnt > 0);
--    if (--acb->refcnt == 0) {
--        g_free(acb);
--    }
--}
--
- /**************************************************************/
- /* Coroutine block device emulation */
-diff --git a/stubs/linux-aio.c b/stubs/linux-aio.c
-new file mode 100644
-index XXXXXXX..XXXXXXX
---- /dev/null
-+++ b/stubs/linux-aio.c
-@@ -XXX,XX +XXX,XX @@
-+/*
-+ * Linux native AIO support.
-+ *
-+ * Copyright (C) 2009 IBM, Corp.
-+ * Copyright (C) 2009 Red Hat, Inc.
-+ *
-+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
-+ * See the COPYING file in the top-level directory.
-+ */
-+#include "qemu/osdep.h"
-+#include "block/aio.h"
-+#include "block/raw-aio.h"
-+
-+void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context)
-+{
-+    abort();
-+}
-+
-+void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context)
-+{
-+    abort();
-+}
-+
-+LinuxAioState *laio_init(void)
-+{
-+    abort();
-+}
-+
-+void laio_cleanup(LinuxAioState *s)
-+{
-+    abort();
-+}
-diff --git a/stubs/set-fd-handler.c b/stubs/set-fd-handler.c
-index XXXXXXX..XXXXXXX 100644
---- a/stubs/set-fd-handler.c
-+++ b/stubs/set-fd-handler.c
-@@ -XXX,XX +XXX,XX @@ void qemu_set_fd_handler(int fd,
- {
-     abort();
- }
--
--void aio_set_fd_handler(AioContext *ctx,
--                        int fd,
--                        bool is_external,
--                        IOHandler *io_read,
--                        IOHandler *io_write,
--                        AioPollFn *io_poll,
--                        void *opaque)
--{
--    abort();
--}
-diff --git a/aio-posix.c b/util/aio-posix.c
-similarity index 99%
-rename from aio-posix.c
-rename to util/aio-posix.c
-index XXXXXXX..XXXXXXX 100644
---- a/aio-posix.c
-+++ b/util/aio-posix.c
-@@ -XXX,XX +XXX,XX @@
- #include "qemu/rcu_queue.h"
- #include "qemu/sockets.h"
- #include "qemu/cutils.h"
--#include "trace-root.h"
-+#include "trace.h"
- #ifdef CONFIG_EPOLL_CREATE1
- #include <sys/epoll.h>
- #endif
-diff --git a/aio-win32.c b/util/aio-win32.c
-similarity index 100%
-rename from aio-win32.c
-rename to util/aio-win32.c
-diff --git a/util/aiocb.c b/util/aiocb.c
-new file mode 100644
-index XXXXXXX..XXXXXXX
---- /dev/null
-+++ b/util/aiocb.c
-@@ -XXX,XX +XXX,XX @@
-+/*
-+ * BlockAIOCB allocation
-+ *
-+ * Copyright (c) 2003-2017 Fabrice Bellard and other QEMU contributors
-+ *
-+ * Permission is hereby granted, free of charge, to any person obtaining a copy
-+ * of this software and associated documentation files (the "Software"), to deal
-+ * in the Software without restriction, including without limitation the rights
-+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-+ * copies of the Software, and to permit persons to whom the Software is
-+ * furnished to do so, subject to the following conditions:
-+ *
-+ * The above copyright notice and this permission notice shall be included in
-+ * all copies or substantial portions of the Software.
-+ *
-+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
-+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-+ * THE SOFTWARE.
-+ */
-+
-+#include "qemu/osdep.h"
-+#include "block/aio.h"
-+
-+void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
-+                   BlockCompletionFunc *cb, void *opaque)
-+{
-+    BlockAIOCB *acb;
-+
-+    acb = g_malloc(aiocb_info->aiocb_size);
-+    acb->aiocb_info = aiocb_info;
-+    acb->bs = bs;
-+    acb->cb = cb;
-+    acb->opaque = opaque;
-+    acb->refcnt = 1;
-+    return acb;
-+}
-+
-+void qemu_aio_ref(void *p)
-+{
-+    BlockAIOCB *acb = p;
-+    acb->refcnt++;
-+}
-+
-+void qemu_aio_unref(void *p)
-+{
-+    BlockAIOCB *acb = p;
-+    assert(acb->refcnt > 0);
-+    if (--acb->refcnt == 0) {
-+        g_free(acb);
-+    }
-+}
-diff --git a/async.c b/util/async.c
-similarity index 99%
-rename from async.c
-rename to util/async.c
-index XXXXXXX..XXXXXXX 100644
---- a/async.c
-+++ b/util/async.c
-@@ -XXX,XX +XXX,XX @@
- /*
-- * QEMU System Emulator
-+ * Data plane event loop
-  *
-  * Copyright (c) 2003-2008 Fabrice Bellard
-+ * Copyright (c) 2009-2017 QEMU contributors
-  *
-  * Permission is hereby granted, free of charge, to any person obtaining a copy
-  * of this software and associated documentation files (the "Software"), to deal
-diff --git a/iohandler.c b/util/iohandler.c
-similarity index 100%
-rename from iohandler.c
-rename to util/iohandler.c
-diff --git a/main-loop.c b/util/main-loop.c
-similarity index 100%
-rename from main-loop.c
-rename to util/main-loop.c
-diff --git a/qemu-timer.c b/util/qemu-timer.c
-similarity index 100%
-rename from qemu-timer.c
-rename to util/qemu-timer.c
-diff --git a/thread-pool.c b/util/thread-pool.c
-similarity index 99%
-rename from thread-pool.c
-rename to util/thread-pool.c
-index XXXXXXX..XXXXXXX 100644
---- a/thread-pool.c
-+++ b/util/thread-pool.c
-@@ -XXX,XX +XXX,XX @@
- #include "qemu/queue.h"
- #include "qemu/thread.h"
- #include "qemu/coroutine.h"
--#include "trace-root.h"
-+#include "trace.h"
- #include "block/thread-pool.h"
- #include "qemu/main-loop.h"
-diff --git a/trace-events b/trace-events
-index XXXXXXX..XXXXXXX 100644
---- a/trace-events
-+++ b/trace-events
-@@ -XXX,XX +XXX,XX @@
- #
- # The <format-string> should be a sprintf()-compatible format string.
--# aio-posix.c
--run_poll_handlers_begin(void *ctx, int64_t max_ns) "ctx %p max_ns %"PRId64
--run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d"
--poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
--poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
--
--# thread-pool.c
--thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p"
--thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d"
--thread_pool_cancel(void *req, void *opaque) "req %p opaque %p"
--
- # ioport.c
- cpu_in(unsigned int addr, char size, unsigned int val) "addr %#x(%c) value %u"
- cpu_out(unsigned int addr, char size, unsigned int val) "addr %#x(%c) value %u"
-diff --git a/util/trace-events b/util/trace-events
-index XXXXXXX..XXXXXXX 100644
---- a/util/trace-events
-+++ b/util/trace-events
-@@ -XXX,XX +XXX,XX @@
- # See docs/tracing.txt for syntax documentation.
-+# util/aio-posix.c
-+run_poll_handlers_begin(void *ctx, int64_t max_ns) "ctx %p max_ns %"PRId64
-+run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d"
-+poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
-+poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
-+
-+# util/thread-pool.c
-+thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p"
-+thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d"
-+thread_pool_cancel(void *req, void *opaque) "req %p opaque %p"
-+
- # util/buffer.c
- buffer_resize(const char *buf, size_t olen, size_t len) "%s: old %zd, new %zd"
- buffer_move_empty(const char *buf, size_t len, const char *from) "%s: %zd bytes from %s"
---
-.9.3

-[Qemu-devel] [PULL v2 02/24] aio: introduce aio_co_schedule and aio_co_wake
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-aio_co_wake provides the infrastructure to start a coroutine on a "home"
-AioContext.  It will be used by CoMutex and CoQueue, so that coroutines
-don't jump from one context to another when they go to sleep on a
-mutex or waitqueue.  However, it can also be used as a more efficient
-alternative to one-shot bottom halves, and saves the effort of tracking
-which AioContext a coroutine is running on.
-aio_co_schedule is the part of aio_co_wake that starts a coroutine
-on a remove AioContext, but it is also useful to implement e.g.
-bdrv_set_aio_context callbacks.
-The implementation of aio_co_schedule is based on a lock-free
-multiple-producer, single-consumer queue.  The multiple producers use
-cmpxchg to add to a LIFO stack.  The consumer (a per-AioContext bottom
-half) grabs all items added so far, inverts the list to make it FIFO,
-and goes through it one item at a time until it's empty.  The data
-structure was inspired by OSv, which uses it in the very code we'll
-"port" to QEMU for the thread-safe CoMutex.
-Most of the new code is really tests.
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213135235.12274-3-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- tests/Makefile.include       |   8 +-
- include/block/aio.h          |  32 +++++++
- include/qemu/coroutine_int.h |  11 ++-
- tests/iothread.h             |  25 +++++
- tests/iothread.c             |  91 ++++++++++++++++++
- tests/test-aio-multithread.c | 213 +++++++++++++++++++++++++++++++++++++++++++
- util/async.c                 |  65 +++++++++++++
- util/qemu-coroutine.c        |   8 ++
- util/trace-events            |   4 +
-files changed, 453 insertions(+), 4 deletions(-)
- create mode 100644 tests/iothread.h
- create mode 100644 tests/iothread.c
- create mode 100644 tests/test-aio-multithread.c
-diff --git a/tests/Makefile.include b/tests/Makefile.include
-index XXXXXXX..XXXXXXX 100644
---- a/tests/Makefile.include
-+++ b/tests/Makefile.include
-@@ -XXX,XX +XXX,XX @@ check-unit-y += tests/test-aio$(EXESUF)
- gcov-files-test-aio-y = util/async.c util/qemu-timer.o
- gcov-files-test-aio-$(CONFIG_WIN32) += util/aio-win32.c
- gcov-files-test-aio-$(CONFIG_POSIX) += util/aio-posix.c
-+check-unit-y += tests/test-aio-multithread$(EXESUF)
-+gcov-files-test-aio-multithread-y = $(gcov-files-test-aio-y)
-+gcov-files-test-aio-multithread-y += util/qemu-coroutine.c tests/iothread.c
- check-unit-y += tests/test-throttle$(EXESUF)
--gcov-files-test-aio-$(CONFIG_WIN32) = aio-win32.c
--gcov-files-test-aio-$(CONFIG_POSIX) = aio-posix.c
- check-unit-y += tests/test-thread-pool$(EXESUF)
- gcov-files-test-thread-pool-y = thread-pool.c
- gcov-files-test-hbitmap-y = util/hbitmap.c
-@@ -XXX,XX +XXX,XX @@ test-qapi-obj-y = tests/test-qapi-visit.o tests/test-qapi-types.o \
-     $(test-qom-obj-y)
- test-crypto-obj-y = $(crypto-obj-y) $(test-qom-obj-y)
- test-io-obj-y = $(io-obj-y) $(test-crypto-obj-y)
--test-block-obj-y = $(block-obj-y) $(test-io-obj-y)
-+test-block-obj-y = $(block-obj-y) $(test-io-obj-y) tests/iothread.o
- tests/check-qint$(EXESUF): tests/check-qint.o $(test-util-obj-y)
- tests/check-qstring$(EXESUF): tests/check-qstring.o $(test-util-obj-y)
-@@ -XXX,XX +XXX,XX @@ tests/check-qom-proplist$(EXESUF): tests/check-qom-proplist.o $(test-qom-obj-y)
- tests/test-char$(EXESUF): tests/test-char.o $(test-util-obj-y) $(qtest-obj-y) $(test-io-obj-y) $(chardev-obj-y)
- tests/test-coroutine$(EXESUF): tests/test-coroutine.o $(test-block-obj-y)
- tests/test-aio$(EXESUF): tests/test-aio.o $(test-block-obj-y)
-+tests/test-aio-multithread$(EXESUF): tests/test-aio-multithread.o $(test-block-obj-y)
- tests/test-throttle$(EXESUF): tests/test-throttle.o $(test-block-obj-y)
- tests/test-blockjob$(EXESUF): tests/test-blockjob.o $(test-block-obj-y) $(test-util-obj-y)
- tests/test-blockjob-txn$(EXESUF): tests/test-blockjob-txn.o $(test-block-obj-y) $(test-util-obj-y)
-diff --git a/include/block/aio.h b/include/block/aio.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/block/aio.h
-+++ b/include/block/aio.h
-@@ -XXX,XX +XXX,XX @@ typedef void QEMUBHFunc(void *opaque);
- typedef bool AioPollFn(void *opaque);
- typedef void IOHandler(void *opaque);
-+struct Coroutine;
- struct ThreadPool;
- struct LinuxAioState;
-@@ -XXX,XX +XXX,XX @@ struct AioContext {
-     bool notified;
-     EventNotifier notifier;
-+    QSLIST_HEAD(, Coroutine) scheduled_coroutines;
-+    QEMUBH *co_schedule_bh;
-+
-     /* Thread pool for performing work and receiving completion callbacks.
-      * Has its own locking.
-      */
-@@ -XXX,XX +XXX,XX @@ static inline bool aio_node_check(AioContext *ctx, bool is_external)
- }
- /**
-+ * aio_co_schedule:
-+ * @ctx: the aio context
-+ * @co: the coroutine
-+ *
-+ * Start a coroutine on a remote AioContext.
-+ *
-+ * The coroutine must not be entered by anyone else while aio_co_schedule()
-+ * is active.  In addition the coroutine must have yielded unless ctx
-+ * is the context in which the coroutine is running (i.e. the value of
-+ * qemu_get_current_aio_context() from the coroutine itself).
-+ */
-+void aio_co_schedule(AioContext *ctx, struct Coroutine *co);
-+
-+/**
-+ * aio_co_wake:
-+ * @co: the coroutine
-+ *
-+ * Restart a coroutine on the AioContext where it was running last, thus
-+ * preventing coroutines from jumping from one context to another when they
-+ * go to sleep.
-+ *
-+ * aio_co_wake may be executed either in coroutine or non-coroutine
-+ * context.  The coroutine must not be entered by anyone else while
-+ * aio_co_wake() is active.
-+ */
-+void aio_co_wake(struct Coroutine *co);
-+
-+/**
-  * Return the AioContext whose event loop runs in the current thread.
-  *
-  * If called from an IOThread this will be the IOThread's AioContext.  If
-diff --git a/include/qemu/coroutine_int.h b/include/qemu/coroutine_int.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/qemu/coroutine_int.h
-+++ b/include/qemu/coroutine_int.h
-@@ -XXX,XX +XXX,XX @@ struct Coroutine {
-     CoroutineEntry *entry;
-     void *entry_arg;
-     Coroutine *caller;
-+
-+    /* Only used when the coroutine has terminated.  */
-     QSLIST_ENTRY(Coroutine) pool_next;
-+
-     size_t locks_held;
--    /* Coroutines that should be woken up when we yield or terminate */
-+    /* Coroutines that should be woken up when we yield or terminate.
-+     * Only used when the coroutine is running.
-+     */
-     QSIMPLEQ_HEAD(, Coroutine) co_queue_wakeup;
-+
-+    /* Only used when the coroutine has yielded.  */
-+    AioContext *ctx;
-     QSIMPLEQ_ENTRY(Coroutine) co_queue_next;
-+    QSLIST_ENTRY(Coroutine) co_scheduled_next;
- };
- Coroutine *qemu_coroutine_new(void);
-diff --git a/tests/iothread.h b/tests/iothread.h
-new file mode 100644
-index XXXXXXX..XXXXXXX
---- /dev/null
-+++ b/tests/iothread.h
-@@ -XXX,XX +XXX,XX @@
-+/*
-+ * Event loop thread implementation for unit tests
-+ *
-+ * Copyright Red Hat Inc., 2013, 2016
-+ *
-+ * Authors:
-+ *  Stefan Hajnoczi   <stefanha@redhat.com>
-+ *  Paolo Bonzini     <pbonzini@redhat.com>
-+ *
-+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
-+ * See the COPYING file in the top-level directory.
-+ */
-+#ifndef TEST_IOTHREAD_H
-+#define TEST_IOTHREAD_H
-+
-+#include "block/aio.h"
-+#include "qemu/thread.h"
-+
-+typedef struct IOThread IOThread;
-+
-+IOThread *iothread_new(void);
-+void iothread_join(IOThread *iothread);
-+AioContext *iothread_get_aio_context(IOThread *iothread);
-+
-+#endif
-diff --git a/tests/iothread.c b/tests/iothread.c
-new file mode 100644
-index XXXXXXX..XXXXXXX
---- /dev/null
-+++ b/tests/iothread.c
-@@ -XXX,XX +XXX,XX @@
-+/*
-+ * Event loop thread implementation for unit tests
-+ *
-+ * Copyright Red Hat Inc., 2013, 2016
-+ *
-+ * Authors:
-+ *  Stefan Hajnoczi   <stefanha@redhat.com>
-+ *  Paolo Bonzini     <pbonzini@redhat.com>
-+ *
-+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
-+ * See the COPYING file in the top-level directory.
-+ *
-+ */
-+
-+#include "qemu/osdep.h"
-+#include "qapi/error.h"
-+#include "block/aio.h"
-+#include "qemu/main-loop.h"
-+#include "qemu/rcu.h"
-+#include "iothread.h"
-+
-+struct IOThread {
-+    AioContext *ctx;
-+
-+    QemuThread thread;
-+    QemuMutex init_done_lock;
-+    QemuCond init_done_cond;    /* is thread initialization done? */
-+    bool stopping;
-+};
-+
-+static __thread IOThread *my_iothread;
-+
-+AioContext *qemu_get_current_aio_context(void)
-+{
-+    return my_iothread ? my_iothread->ctx : qemu_get_aio_context();
-+}
-+
-+static void *iothread_run(void *opaque)
-+{
-+    IOThread *iothread = opaque;
-+
-+    rcu_register_thread();
-+
-+    my_iothread = iothread;
-+    qemu_mutex_lock(&iothread->init_done_lock);
-+    iothread->ctx = aio_context_new(&error_abort);
-+    qemu_cond_signal(&iothread->init_done_cond);
-+    qemu_mutex_unlock(&iothread->init_done_lock);
-+
-+    while (!atomic_read(&iothread->stopping)) {
-+        aio_poll(iothread->ctx, true);
-+    }
-+
-+    rcu_unregister_thread();
-+    return NULL;
-+}
-+
-+void iothread_join(IOThread *iothread)
-+{
-+    iothread->stopping = true;
-+    aio_notify(iothread->ctx);
-+    qemu_thread_join(&iothread->thread);
-+    qemu_cond_destroy(&iothread->init_done_cond);
-+    qemu_mutex_destroy(&iothread->init_done_lock);
-+    aio_context_unref(iothread->ctx);
-+    g_free(iothread);
-+}
-+
-+IOThread *iothread_new(void)
-+{
-+    IOThread *iothread = g_new0(IOThread, 1);
-+
-+    qemu_mutex_init(&iothread->init_done_lock);
-+    qemu_cond_init(&iothread->init_done_cond);
-+    qemu_thread_create(&iothread->thread, NULL, iothread_run,
-+                       iothread, QEMU_THREAD_JOINABLE);
-+
-+    /* Wait for initialization to complete */
-+    qemu_mutex_lock(&iothread->init_done_lock);
-+    while (iothread->ctx == NULL) {
-+        qemu_cond_wait(&iothread->init_done_cond,
-+                       &iothread->init_done_lock);
-+    }
-+    qemu_mutex_unlock(&iothread->init_done_lock);
-+    return iothread;
-+}
-+
-+AioContext *iothread_get_aio_context(IOThread *iothread)
-+{
-+    return iothread->ctx;
-+}
-diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c
-new file mode 100644
-index XXXXXXX..XXXXXXX
---- /dev/null
-+++ b/tests/test-aio-multithread.c
-@@ -XXX,XX +XXX,XX @@
-+/*
-+ * AioContext multithreading tests
-+ *
-+ * Copyright Red Hat, Inc. 2016
-+ *
-+ * Authors:
-+ *  Paolo Bonzini    <pbonzini@redhat.com>
-+ *
-+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
-+ * See the COPYING.LIB file in the top-level directory.
-+ */
-+
-+#include "qemu/osdep.h"
-+#include <glib.h>
-+#include "block/aio.h"
-+#include "qapi/error.h"
-+#include "qemu/coroutine.h"
-+#include "qemu/thread.h"
-+#include "qemu/error-report.h"
-+#include "iothread.h"
-+
-+/* AioContext management */
-+
-+#define NUM_CONTEXTS 5
-+
-+static IOThread *threads[NUM_CONTEXTS];
-+static AioContext *ctx[NUM_CONTEXTS];
-+static __thread int id = -1;
-+
-+static QemuEvent done_event;
-+
-+/* Run a function synchronously on a remote iothread. */
-+
-+typedef struct CtxRunData {
-+    QEMUBHFunc *cb;
-+    void *arg;
-+} CtxRunData;
-+
-+static void ctx_run_bh_cb(void *opaque)
-+{
-+    CtxRunData *data = opaque;
-+
-+    data->cb(data->arg);
-+    qemu_event_set(&done_event);
-+}
-+
-+static void ctx_run(int i, QEMUBHFunc *cb, void *opaque)
-+{
-+    CtxRunData data = {
-+        .cb = cb,
-+        .arg = opaque
-+    };
-+
-+    qemu_event_reset(&done_event);
-+    aio_bh_schedule_oneshot(ctx[i], ctx_run_bh_cb, &data);
-+    qemu_event_wait(&done_event);
-+}
-+
-+/* Starting the iothreads. */
-+
-+static void set_id_cb(void *opaque)
-+{
-+    int *i = opaque;
-+
-+    id = *i;
-+}
-+
-+static void create_aio_contexts(void)
-+{
-+    int i;
-+
-+    for (i = 0; i < NUM_CONTEXTS; i++) {
-+        threads[i] = iothread_new();
-+        ctx[i] = iothread_get_aio_context(threads[i]);
-+    }
-+
-+    qemu_event_init(&done_event, false);
-+    for (i = 0; i < NUM_CONTEXTS; i++) {
-+        ctx_run(i, set_id_cb, &i);
-+    }
-+}
-+
-+/* Stopping the iothreads. */
-+
-+static void join_aio_contexts(void)
-+{
-+    int i;
-+
-+    for (i = 0; i < NUM_CONTEXTS; i++) {
-+        aio_context_ref(ctx[i]);
-+    }
-+    for (i = 0; i < NUM_CONTEXTS; i++) {
-+        iothread_join(threads[i]);
-+    }
-+    for (i = 0; i < NUM_CONTEXTS; i++) {
-+        aio_context_unref(ctx[i]);
-+    }
-+    qemu_event_destroy(&done_event);
-+}
-+
-+/* Basic test for the stuff above. */
-+
-+static void test_lifecycle(void)
-+{
-+    create_aio_contexts();
-+    join_aio_contexts();
-+}
-+
-+/* aio_co_schedule test.  */
-+
-+static Coroutine *to_schedule[NUM_CONTEXTS];
-+
-+static bool now_stopping;
-+
-+static int count_retry;
-+static int count_here;
-+static int count_other;
-+
-+static bool schedule_next(int n)
-+{
-+    Coroutine *co;
-+
-+    co = atomic_xchg(&to_schedule[n], NULL);
-+    if (!co) {
-+        atomic_inc(&count_retry);
-+        return false;
-+    }
-+
-+    if (n == id) {
-+        atomic_inc(&count_here);
-+    } else {
-+        atomic_inc(&count_other);
-+    }
-+
-+    aio_co_schedule(ctx[n], co);
-+    return true;
-+}
-+
-+static void finish_cb(void *opaque)
-+{
-+    schedule_next(id);
-+}
-+
-+static coroutine_fn void test_multi_co_schedule_entry(void *opaque)
-+{
-+    g_assert(to_schedule[id] == NULL);
-+    atomic_mb_set(&to_schedule[id], qemu_coroutine_self());
-+
-+    while (!atomic_mb_read(&now_stopping)) {
-+        int n;
-+
-+        n = g_test_rand_int_range(0, NUM_CONTEXTS);
-+        schedule_next(n);
-+        qemu_coroutine_yield();
-+
-+        g_assert(to_schedule[id] == NULL);
-+        atomic_mb_set(&to_schedule[id], qemu_coroutine_self());
-+    }
-+}
-+
-+
-+static void test_multi_co_schedule(int seconds)
-+{
-+    int i;
-+
-+    count_here = count_other = count_retry = 0;
-+    now_stopping = false;
-+
-+    create_aio_contexts();
-+    for (i = 0; i < NUM_CONTEXTS; i++) {
-+        Coroutine *co1 = qemu_coroutine_create(test_multi_co_schedule_entry, NULL);
-+        aio_co_schedule(ctx[i], co1);
-+    }
-+
-+    g_usleep(seconds * 1000000);
-+
-+    atomic_mb_set(&now_stopping, true);
-+    for (i = 0; i < NUM_CONTEXTS; i++) {
-+        ctx_run(i, finish_cb, NULL);
-+        to_schedule[i] = NULL;
-+    }
-+
-+    join_aio_contexts();
-+    g_test_message("scheduled %d, queued %d, retry %d, total %d\n",
-+                  count_other, count_here, count_retry,
-+                  count_here + count_other + count_retry);
-+}
-+
-+static void test_multi_co_schedule_1(void)
-+{
-+    test_multi_co_schedule(1);
-+}
-+
-+static void test_multi_co_schedule_10(void)
-+{
-+    test_multi_co_schedule(10);
-+}
-+
-+/* End of tests.  */
-+
-+int main(int argc, char **argv)
-+{
-+    init_clocks();
-+
-+    g_test_init(&argc, &argv, NULL);
-+    g_test_add_func("/aio/multi/lifecycle", test_lifecycle);
-+    if (g_test_quick()) {
-+        g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_1);
-+    } else {
-+        g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_10);
-+    }
-+    return g_test_run();
-+}
-diff --git a/util/async.c b/util/async.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/async.c
-+++ b/util/async.c
-@@ -XXX,XX +XXX,XX @@
- #include "qemu/main-loop.h"
- #include "qemu/atomic.h"
- #include "block/raw-aio.h"
-+#include "qemu/coroutine_int.h"
-+#include "trace.h"
- /***********************************************************/
- /* bottom halves (can be seen as timers which expire ASAP) */
-@@ -XXX,XX +XXX,XX @@ aio_ctx_finalize(GSource     *source)
-     }
- #endif
-+    assert(QSLIST_EMPTY(&ctx->scheduled_coroutines));
-+    qemu_bh_delete(ctx->co_schedule_bh);
-+
-     qemu_lockcnt_lock(&ctx->list_lock);
-     assert(!qemu_lockcnt_count(&ctx->list_lock));
-     while (ctx->first_bh) {
-@@ -XXX,XX +XXX,XX @@ static bool event_notifier_poll(void *opaque)
-     return atomic_read(&ctx->notified);
- }
-+static void co_schedule_bh_cb(void *opaque)
-+{
-+    AioContext *ctx = opaque;
-+    QSLIST_HEAD(, Coroutine) straight, reversed;
-+
-+    QSLIST_MOVE_ATOMIC(&reversed, &ctx->scheduled_coroutines);
-+    QSLIST_INIT(&straight);
-+
-+    while (!QSLIST_EMPTY(&reversed)) {
-+        Coroutine *co = QSLIST_FIRST(&reversed);
-+        QSLIST_REMOVE_HEAD(&reversed, co_scheduled_next);
-+        QSLIST_INSERT_HEAD(&straight, co, co_scheduled_next);
-+    }
-+
-+    while (!QSLIST_EMPTY(&straight)) {
-+        Coroutine *co = QSLIST_FIRST(&straight);
-+        QSLIST_REMOVE_HEAD(&straight, co_scheduled_next);
-+        trace_aio_co_schedule_bh_cb(ctx, co);
-+        qemu_coroutine_enter(co);
-+    }
-+}
-+
- AioContext *aio_context_new(Error **errp)
- {
-     int ret;
-@@ -XXX,XX +XXX,XX @@ AioContext *aio_context_new(Error **errp)
-     }
-     g_source_set_can_recurse(&ctx->source, true);
-     qemu_lockcnt_init(&ctx->list_lock);
-+
-+    ctx->co_schedule_bh = aio_bh_new(ctx, co_schedule_bh_cb, ctx);
-+    QSLIST_INIT(&ctx->scheduled_coroutines);
-+
-     aio_set_event_notifier(ctx, &ctx->notifier,
-                            false,
-                            (EventNotifierHandler *)
-@@ -XXX,XX +XXX,XX @@ fail:
-     return NULL;
- }
-+void aio_co_schedule(AioContext *ctx, Coroutine *co)
-+{
-+    trace_aio_co_schedule(ctx, co);
-+    QSLIST_INSERT_HEAD_ATOMIC(&ctx->scheduled_coroutines,
-+                              co, co_scheduled_next);
-+    qemu_bh_schedule(ctx->co_schedule_bh);
-+}
-+
-+void aio_co_wake(struct Coroutine *co)
-+{
-+    AioContext *ctx;
-+
-+    /* Read coroutine before co->ctx.  Matches smp_wmb in
-+     * qemu_coroutine_enter.
-+     */
-+    smp_read_barrier_depends();
-+    ctx = atomic_read(&co->ctx);
-+
-+    if (ctx != qemu_get_current_aio_context()) {
-+        aio_co_schedule(ctx, co);
-+        return;
-+    }
-+
-+    if (qemu_in_coroutine()) {
-+        Coroutine *self = qemu_coroutine_self();
-+        assert(self != co);
-+        QSIMPLEQ_INSERT_TAIL(&self->co_queue_wakeup, co, co_queue_next);
-+    } else {
-+        aio_context_acquire(ctx);
-+        qemu_coroutine_enter(co);
-+        aio_context_release(ctx);
-+    }
-+}
-+
- void aio_context_ref(AioContext *ctx)
- {
-     g_source_ref(&ctx->source);
-diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/qemu-coroutine.c
-+++ b/util/qemu-coroutine.c
-@@ -XXX,XX +XXX,XX @@
- #include "qemu/atomic.h"
- #include "qemu/coroutine.h"
- #include "qemu/coroutine_int.h"
-+#include "block/aio.h"
- enum {
-     POOL_BATCH_SIZE = 64,
-@@ -XXX,XX +XXX,XX @@ void qemu_coroutine_enter(Coroutine *co)
-     }
-     co->caller = self;
-+    co->ctx = qemu_get_current_aio_context();
-+
-+    /* Store co->ctx before anything that stores co.  Matches
-+     * barrier in aio_co_wake.
-+     */
-+    smp_wmb();
-+
-     ret = qemu_coroutine_switch(self, co, COROUTINE_ENTER);
-     qemu_co_queue_run_restart(co);
-diff --git a/util/trace-events b/util/trace-events
-index XXXXXXX..XXXXXXX 100644
---- a/util/trace-events
-+++ b/util/trace-events
-@@ -XXX,XX +XXX,XX @@ run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d"
- poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
- poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
-+# util/async.c
-+aio_co_schedule(void *ctx, void *co) "ctx %p co %p"
-+aio_co_schedule_bh_cb(void *ctx, void *co) "ctx %p co %p"
-+
- # util/thread-pool.c
- thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p"
- thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d"
---
-.9.3

-[Qemu-devel] [PULL v2 03/24] block-backend: allow blk_prw from coroutine context
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-qcow2_create2 calls this.  Do not run a nested event loop, as that
-breaks when aio_co_wake tries to queue the coroutine on the co_queue_wakeup
-list of the currently running one.
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213135235.12274-4-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- block/block-backend.c | 12 ++++++++----
-file changed, 8 insertions(+), 4 deletions(-)
-diff --git a/block/block-backend.c b/block/block-backend.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/block-backend.c
-+++ b/block/block-backend.c
-@@ -XXX,XX +XXX,XX @@ static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf,
- {
-     QEMUIOVector qiov;
-     struct iovec iov;
--    Coroutine *co;
-     BlkRwCo rwco;
-     iov = (struct iovec) {
-@@ -XXX,XX +XXX,XX @@ static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf,
-         .ret    = NOT_DONE,
-     };
--    co = qemu_coroutine_create(co_entry, &rwco);
--    qemu_coroutine_enter(co);
--    BDRV_POLL_WHILE(blk_bs(blk), rwco.ret == NOT_DONE);
-+    if (qemu_in_coroutine()) {
-+        /* Fast-path if already in coroutine context */
-+        co_entry(&rwco);
-+    } else {
-+        Coroutine *co = qemu_coroutine_create(co_entry, &rwco);
-+        qemu_coroutine_enter(co);
-+        BDRV_POLL_WHILE(blk_bs(blk), rwco.ret == NOT_DONE);
-+    }
-     return rwco.ret;
- }
---
-.9.3

-[Qemu-devel] [PULL v2 04/24] test-thread-pool: use generic AioContext infrastructure
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-Once the thread pool starts using aio_co_wake, it will also need
-qemu_get_current_aio_context().  Make test-thread-pool create
-an AioContext with qemu_init_main_loop, so that stubs/iothread.c
-and tests/iothread.c can provide the rest.
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213135235.12274-5-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- tests/test-thread-pool.c | 12 +++---------
-file changed, 3 insertions(+), 9 deletions(-)
-diff --git a/tests/test-thread-pool.c b/tests/test-thread-pool.c
-index XXXXXXX..XXXXXXX 100644
---- a/tests/test-thread-pool.c
-+++ b/tests/test-thread-pool.c
-@@ -XXX,XX +XXX,XX @@
- #include "qapi/error.h"
- #include "qemu/timer.h"
- #include "qemu/error-report.h"
-+#include "qemu/main-loop.h"
- static AioContext *ctx;
- static ThreadPool *pool;
-@@ -XXX,XX +XXX,XX @@ static void test_cancel_async(void)
- int main(int argc, char **argv)
- {
-     int ret;
--    Error *local_error = NULL;
--    init_clocks();
--
--    ctx = aio_context_new(&local_error);
--    if (!ctx) {
--        error_reportf_err(local_error, "Failed to create AIO Context: ");
--        exit(1);
--    }
-+    qemu_init_main_loop(&error_abort);
-+    ctx = qemu_get_current_aio_context();
-     pool = aio_get_thread_pool(ctx);
-     g_test_init(&argc, &argv, NULL);
-@@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv)
-     ret = g_test_run();
--    aio_context_unref(ctx);
-     return ret;
- }
---
-.9.3

-[Qemu-devel] [PULL v2 05/24] io: add methods to set I/O handlers on AioContext
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-This is in preparation for making qio_channel_yield work on
-AioContexts other than the main one.
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213135235.12274-6-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- include/io/channel.h | 25 +++++++++++++++++++++++++
- io/channel-command.c | 13 +++++++++++++
- io/channel-file.c    | 11 +++++++++++
- io/channel-socket.c  | 16 +++++++++++-----
- io/channel-tls.c     | 12 ++++++++++++
- io/channel-watch.c   |  6 ++++++
- io/channel.c         | 11 +++++++++++
-files changed, 89 insertions(+), 5 deletions(-)
-diff --git a/include/io/channel.h b/include/io/channel.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/io/channel.h
-+++ b/include/io/channel.h
-@@ -XXX,XX +XXX,XX @@
- #include "qemu-common.h"
- #include "qom/object.h"
-+#include "block/aio.h"
- #define TYPE_QIO_CHANNEL "qio-channel"
- #define QIO_CHANNEL(obj)                                    \
-@@ -XXX,XX +XXX,XX @@ struct QIOChannelClass {
-                      off_t offset,
-                      int whence,
-                      Error **errp);
-+    void (*io_set_aio_fd_handler)(QIOChannel *ioc,
-+                                  AioContext *ctx,
-+                                  IOHandler *io_read,
-+                                  IOHandler *io_write,
-+                                  void *opaque);
- };
- /* General I/O handling functions */
-@@ -XXX,XX +XXX,XX @@ void qio_channel_yield(QIOChannel *ioc,
- void qio_channel_wait(QIOChannel *ioc,
-                       GIOCondition condition);
-+/**
-+ * qio_channel_set_aio_fd_handler:
-+ * @ioc: the channel object
-+ * @ctx: the AioContext to set the handlers on
-+ * @io_read: the read handler
-+ * @io_write: the write handler
-+ * @opaque: the opaque value passed to the handler
-+ *
-+ * This is used internally by qio_channel_yield().  It can
-+ * be used by channel implementations to forward the handlers
-+ * to another channel (e.g. from #QIOChannelTLS to the
-+ * underlying socket).
-+ */
-+void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
-+                                    AioContext *ctx,
-+                                    IOHandler *io_read,
-+                                    IOHandler *io_write,
-+                                    void *opaque);
-+
- #endif /* QIO_CHANNEL_H */
-diff --git a/io/channel-command.c b/io/channel-command.c
-index XXXXXXX..XXXXXXX 100644
---- a/io/channel-command.c
-+++ b/io/channel-command.c
-@@ -XXX,XX +XXX,XX @@ static int qio_channel_command_close(QIOChannel *ioc,
- }
-+static void qio_channel_command_set_aio_fd_handler(QIOChannel *ioc,
-+                                                   AioContext *ctx,
-+                                                   IOHandler *io_read,
-+                                                   IOHandler *io_write,
-+                                                   void *opaque)
-+{
-+    QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
-+    aio_set_fd_handler(ctx, cioc->readfd, false, io_read, NULL, NULL, opaque);
-+    aio_set_fd_handler(ctx, cioc->writefd, false, NULL, io_write, NULL, opaque);
-+}
-+
-+
- static GSource *qio_channel_command_create_watch(QIOChannel *ioc,
-                                                  GIOCondition condition)
- {
-@@ -XXX,XX +XXX,XX @@ static void qio_channel_command_class_init(ObjectClass *klass,
-     ioc_klass->io_set_blocking = qio_channel_command_set_blocking;
-     ioc_klass->io_close = qio_channel_command_close;
-     ioc_klass->io_create_watch = qio_channel_command_create_watch;
-+    ioc_klass->io_set_aio_fd_handler = qio_channel_command_set_aio_fd_handler;
- }
- static const TypeInfo qio_channel_command_info = {
-diff --git a/io/channel-file.c b/io/channel-file.c
-index XXXXXXX..XXXXXXX 100644
---- a/io/channel-file.c
-+++ b/io/channel-file.c
-@@ -XXX,XX +XXX,XX @@ static int qio_channel_file_close(QIOChannel *ioc,
- }
-+static void qio_channel_file_set_aio_fd_handler(QIOChannel *ioc,
-+                                                AioContext *ctx,
-+                                                IOHandler *io_read,
-+                                                IOHandler *io_write,
-+                                                void *opaque)
-+{
-+    QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
-+    aio_set_fd_handler(ctx, fioc->fd, false, io_read, io_write, NULL, opaque);
-+}
-+
- static GSource *qio_channel_file_create_watch(QIOChannel *ioc,
-                                               GIOCondition condition)
- {
-@@ -XXX,XX +XXX,XX @@ static void qio_channel_file_class_init(ObjectClass *klass,
-     ioc_klass->io_seek = qio_channel_file_seek;
-     ioc_klass->io_close = qio_channel_file_close;
-     ioc_klass->io_create_watch = qio_channel_file_create_watch;
-+    ioc_klass->io_set_aio_fd_handler = qio_channel_file_set_aio_fd_handler;
- }
- static const TypeInfo qio_channel_file_info = {
-diff --git a/io/channel-socket.c b/io/channel-socket.c
-index XXXXXXX..XXXXXXX 100644
---- a/io/channel-socket.c
-+++ b/io/channel-socket.c
-@@ -XXX,XX +XXX,XX @@ qio_channel_socket_set_blocking(QIOChannel *ioc,
-         qemu_set_block(sioc->fd);
-     } else {
-         qemu_set_nonblock(sioc->fd);
--#ifdef WIN32
--        WSAEventSelect(sioc->fd, ioc->event,
--                       FD_READ | FD_ACCEPT | FD_CLOSE |
--                       FD_CONNECT | FD_WRITE | FD_OOB);
--#endif
-     }
-     return 0;
- }
-@@ -XXX,XX +XXX,XX @@ qio_channel_socket_shutdown(QIOChannel *ioc,
-     return 0;
- }
-+static void qio_channel_socket_set_aio_fd_handler(QIOChannel *ioc,
-+                                                  AioContext *ctx,
-+                                                  IOHandler *io_read,
-+                                                  IOHandler *io_write,
-+                                                  void *opaque)
-+{
-+    QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc);
-+    aio_set_fd_handler(ctx, sioc->fd, false, io_read, io_write, NULL, opaque);
-+}
-+
- static GSource *qio_channel_socket_create_watch(QIOChannel *ioc,
-                                                 GIOCondition condition)
- {
-@@ -XXX,XX +XXX,XX @@ static void qio_channel_socket_class_init(ObjectClass *klass,
-     ioc_klass->io_set_cork = qio_channel_socket_set_cork;
-     ioc_klass->io_set_delay = qio_channel_socket_set_delay;
-     ioc_klass->io_create_watch = qio_channel_socket_create_watch;
-+    ioc_klass->io_set_aio_fd_handler = qio_channel_socket_set_aio_fd_handler;
- }
- static const TypeInfo qio_channel_socket_info = {
-diff --git a/io/channel-tls.c b/io/channel-tls.c
-index XXXXXXX..XXXXXXX 100644
---- a/io/channel-tls.c
-+++ b/io/channel-tls.c
-@@ -XXX,XX +XXX,XX @@ static int qio_channel_tls_close(QIOChannel *ioc,
-     return qio_channel_close(tioc->master, errp);
- }
-+static void qio_channel_tls_set_aio_fd_handler(QIOChannel *ioc,
-+                                               AioContext *ctx,
-+                                               IOHandler *io_read,
-+                                               IOHandler *io_write,
-+                                               void *opaque)
-+{
-+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
-+
-+    qio_channel_set_aio_fd_handler(tioc->master, ctx, io_read, io_write, opaque);
-+}
-+
- static GSource *qio_channel_tls_create_watch(QIOChannel *ioc,
-                                              GIOCondition condition)
- {
-@@ -XXX,XX +XXX,XX @@ static void qio_channel_tls_class_init(ObjectClass *klass,
-     ioc_klass->io_close = qio_channel_tls_close;
-     ioc_klass->io_shutdown = qio_channel_tls_shutdown;
-     ioc_klass->io_create_watch = qio_channel_tls_create_watch;
-+    ioc_klass->io_set_aio_fd_handler = qio_channel_tls_set_aio_fd_handler;
- }
- static const TypeInfo qio_channel_tls_info = {
-diff --git a/io/channel-watch.c b/io/channel-watch.c
-index XXXXXXX..XXXXXXX 100644
---- a/io/channel-watch.c
-+++ b/io/channel-watch.c
-@@ -XXX,XX +XXX,XX @@ GSource *qio_channel_create_socket_watch(QIOChannel *ioc,
-     GSource *source;
-     QIOChannelSocketSource *ssource;
-+#ifdef WIN32
-+    WSAEventSelect(socket, ioc->event,
-+                   FD_READ | FD_ACCEPT | FD_CLOSE |
-+                   FD_CONNECT | FD_WRITE | FD_OOB);
-+#endif
-+
-     source = g_source_new(&qio_channel_socket_source_funcs,
-                           sizeof(QIOChannelSocketSource));
-     ssource = (QIOChannelSocketSource *)source;
-diff --git a/io/channel.c b/io/channel.c
-index XXXXXXX..XXXXXXX 100644
---- a/io/channel.c
-+++ b/io/channel.c
-@@ -XXX,XX +XXX,XX @@ GSource *qio_channel_create_watch(QIOChannel *ioc,
- }
-+void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
-+                                    AioContext *ctx,
-+                                    IOHandler *io_read,
-+                                    IOHandler *io_write,
-+                                    void *opaque)
-+{
-+    QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
-+
-+    klass->io_set_aio_fd_handler(ioc, ctx, io_read, io_write, opaque);
-+}
-+
- guint qio_channel_add_watch(QIOChannel *ioc,
-                             GIOCondition condition,
-                             QIOChannelFunc func,
---
-.9.3

-[Qemu-devel] [PULL v2 16/24] aio-posix: partially inline aio_dispatch into aio_poll
+[Qemu-devel] [PULL v2 01/10] tests: fix bdrv-drain leak
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: Marc-André Lureau <marcandre.lureau@redhat.com>
-This patch prepares for the removal of unnecessary lockcnt inc/dec pairs.
+Spotted by ASAN:
 Extract the dispatching loop for file descriptor handlers into a new
 function aio_dispatch_handlers, and then inline aio_dispatch into
 aio_poll.
-aio_dispatch can now become void.
+=================================================================
 ==5378==ERROR: LeakSanitizer: detected memory leaks
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Direct leak of 65536 byte(s) in 1 object(s) allocated from:
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+    #0 0x7f788f83bc48 in malloc (/lib64/libasan.so.5+0xeec48)
-Reviewed-by: Fam Zheng <famz@redhat.com>
+    #1 0x7f788c9923c5 in g_malloc (/lib64/libglib-2.0.so.0+0x523c5)
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
+    #2 0x5622a1fe37bc in coroutine_trampoline /home/elmarco/src/qq/util/coroutine-ucontext.c:116
-Message-id: 20170213135235.12274-17-pbonzini@redhat.com
+    #3 0x7f788a15d75f in __correctly_grouped_prefixwc (/lib64/libc.so.6+0x4c75f)
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 (Broken in commit 4c8158e359d.)
 Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
 Message-id: 20180809114417.28718-3-marcandre.lureau@redhat.com
 Signed-off-by: Max Reitz <mreitz@redhat.com>
 ---
- include/block/aio.h |  6 +-----
+ tests/test-bdrv-drain.c | 1 +
- util/aio-posix.c    | 44 ++++++++++++++------------------------------
+file changed, 1 insertion(+)
  util/aio-win32.c    | 13 ++++---------
  util/async.c        |  2 +-
 files changed, 20 insertions(+), 45 deletions(-)
-diff --git a/include/block/aio.h b/include/block/aio.h
+diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
 index XXXXXXX..XXXXXXX 100644
---- a/include/block/aio.h
+--- a/tests/test-bdrv-drain.c
-+++ b/include/block/aio.h
++++ b/tests/test-bdrv-drain.c
-@@ -XXX,XX +XXX,XX @@ bool aio_pending(AioContext *ctx);
+@@ -XXX,XX +XXX,XX @@ static void coroutine_fn test_co_delete_by_drain(void *opaque)
  /* Dispatch any pending callbacks from the GSource attached to the AioContext.
   *
   * This is used internally in the implementation of the GSource.
 - *
 - * @dispatch_fds: true to process fds, false to skip them
 - *                (can be used as an optimization by callers that know there
 - *                are no fds ready)
   */
 -bool aio_dispatch(AioContext *ctx, bool dispatch_fds);
 +void aio_dispatch(AioContext *ctx);
  /* Progress in completing AIO work to occur.  This can issue new pending
   * aio as a result of executing I/O completion or bh callbacks.
 diff --git a/util/aio-posix.c b/util/aio-posix.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/aio-posix.c
 +++ b/util/aio-posix.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
      AioHandler *node, *tmp;
      bool progress = false;
 -    /*
 -     * We have to walk very carefully in case aio_set_fd_handler is
 -     * called while we're walking.
 -     */
 -    qemu_lockcnt_inc(&ctx->list_lock);
 -
      QLIST_FOREACH_SAFE_RCU(node, &ctx->aio_handlers, node, tmp) {
          int revents;
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
          }
      }
--    qemu_lockcnt_dec(&ctx->list_lock);
+     dbdd->done = true;
-     return progress;
++    g_free(buffer);
  }
--/*
+ /**
 - * Note that dispatch_fds == false has the side-effect of post-poning the
 - * freeing of deleted handlers.
 - */
 -bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
 +void aio_dispatch(AioContext *ctx)
  {
 -    bool progress;
 +    aio_bh_poll(ctx);
 -    /*
 -     * If there are callbacks left that have been queued, we need to call them.
 -     * Do not call select in this case, because it is possible that the caller
 -     * does not need a complete flush (as is the case for aio_poll loops).
 -     */
 -    progress = aio_bh_poll(ctx);
 +    qemu_lockcnt_inc(&ctx->list_lock);
 +    aio_dispatch_handlers(ctx);
 +    qemu_lockcnt_dec(&ctx->list_lock);
 -    if (dispatch_fds) {
 -        progress |= aio_dispatch_handlers(ctx);
 -    }
 -
 -    /* Run our timers */
 -    progress |= timerlistgroup_run_timers(&ctx->tlg);
 -
 -    return progress;
 +    timerlistgroup_run_timers(&ctx->tlg);
  }
  /* These thread-local variables are used only in a small part of aio_poll
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
      npfd = 0;
      qemu_lockcnt_dec(&ctx->list_lock);
 -    /* Run dispatch even if there were no readable fds to run timers */
 -    if (aio_dispatch(ctx, ret > 0)) {
 -        progress = true;
 +    progress |= aio_bh_poll(ctx);
 +
 +    if (ret > 0) {
 +        qemu_lockcnt_inc(&ctx->list_lock);
 +        progress |= aio_dispatch_handlers(ctx);
 +        qemu_lockcnt_dec(&ctx->list_lock);
      }
 +    progress |= timerlistgroup_run_timers(&ctx->tlg);
 +
      return progress;
  }
 diff --git a/util/aio-win32.c b/util/aio-win32.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/aio-win32.c
 +++ b/util/aio-win32.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
      return progress;
  }
 -bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
 +void aio_dispatch(AioContext *ctx)
  {
 -    bool progress;
 -
 -    progress = aio_bh_poll(ctx);
 -    if (dispatch_fds) {
 -        progress |= aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);
 -    }
 -    progress |= timerlistgroup_run_timers(&ctx->tlg);
 -    return progress;
 +    aio_bh_poll(ctx);
 +    aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);
 +    timerlistgroup_run_timers(&ctx->tlg);
  }
  bool aio_poll(AioContext *ctx, bool blocking)
 diff --git a/util/async.c b/util/async.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/async.c
 +++ b/util/async.c
@@ -XXX,XX +XXX,XX @@ aio_ctx_dispatch(GSource     *source,
      AioContext *ctx = (AioContext *) source;
      assert(callback == NULL);
 -    aio_dispatch(ctx, true);
 +    aio_dispatch(ctx);
      return true;
  }
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 09/24] blkdebug: reschedule coroutine on the AioContext it is running on
+[Qemu-devel] [PULL v2 02/10] jobs: change start callback to run callback
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: John Snow <jsnow@redhat.com>
-Keep the coroutine on the same AioContext.  Without this change,
+Presently we codify the entry point for a job as the "start" callback,
-there would be a race between yielding the coroutine and reentering it.
+but a more apt name would be "run" to clarify the idea that when this
-While the race cannot happen now, because the code only runs from a single
+function returns we consider the job to have "finished," except for
-AioContext, this will change with multiqueue support in the block layer.
+any cleanup which occurs in separate callbacks later.
-While doing the change, replace custom bottom half with aio_co_schedule.
+As part of this clarification, change the signature to include an error
+object and a return code. The error ptr is not yet used, and the return
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+code while captured, will be overwritten by actions in the job_completed
-Reviewed-by: Fam Zheng <famz@redhat.com>
+function.
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
+Signed-off-by: John Snow <jsnow@redhat.com>
-Message-id: 20170213135235.12274-10-pbonzini@redhat.com
+Reviewed-by: Max Reitz <mreitz@redhat.com>
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Message-id: 20180830015734.19765-2-jsnow@redhat.com
 Reviewed-by: Jeff Cody <jcody@redhat.com>
 Signed-off-by: Max Reitz <mreitz@redhat.com>
 ---
- block/blkdebug.c | 9 +--------
+ include/qemu/job.h        |  2 +-
-file changed, 1 insertion(+), 8 deletions(-)
+ block/backup.c            |  7 ++++---
+ block/commit.c            |  7 ++++---
-diff --git a/block/blkdebug.c b/block/blkdebug.c
+ block/create.c            |  8 +++++---
-index XXXXXXX..XXXXXXX 100644
+ block/mirror.c            | 10 ++++++----
---- a/block/blkdebug.c
+ block/stream.c            |  7 ++++---
-+++ b/block/blkdebug.c
+ job.c                     |  6 +++---
  tests/test-bdrv-drain.c   |  7 ++++---
  tests/test-blockjob-txn.c | 16 ++++++++--------
  tests/test-blockjob.c     |  7 ++++---
 files changed, 43 insertions(+), 34 deletions(-)
 diff --git a/include/qemu/job.h b/include/qemu/job.h
 index XXXXXXX..XXXXXXX 100644
 --- a/include/qemu/job.h
 +++ b/include/qemu/job.h
@@ -XXX,XX +XXX,XX @@ struct JobDriver {
      JobType job_type;
      /** Mandatory: Entrypoint for the Coroutine. */
 -    CoroutineEntry *start;
 +    int coroutine_fn (*run)(Job *job, Error **errp);
      /**
       * If the callback is not NULL, it will be invoked when the job transitions
 diff --git a/block/backup.c b/block/backup.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/backup.c
 +++ b/block/backup.c
@@ -XXX,XX +XXX,XX @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
      bdrv_dirty_iter_free(dbi);
  }
 -static void coroutine_fn backup_run(void *opaque)
 +static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
  {
 -    BackupBlockJob *job = opaque;
 +    BackupBlockJob *job = container_of(opaque_job, BackupBlockJob, common.job);
      BackupCompleteData *data;
      BlockDriverState *bs = blk_bs(job->common.blk);
      int64_t offset, nb_clusters;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn backup_run(void *opaque)
      data = g_malloc(sizeof(*data));
      data->ret = ret;
      job_defer_to_main_loop(&job->common.job, backup_complete, data);
 +    return ret;
  }
  static const BlockJobDriver backup_job_driver = {
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver backup_job_driver = {
          .free                   = block_job_free,
          .user_resume            = block_job_user_resume,
          .drain                  = block_job_drain,
 -        .start                  = backup_run,
 +        .run                    = backup_run,
          .commit                 = backup_commit,
          .abort                  = backup_abort,
          .clean                  = backup_clean,
 diff --git a/block/commit.c b/block/commit.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/commit.c
 +++ b/block/commit.c
@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
      bdrv_unref(top);
  }
 -static void coroutine_fn commit_run(void *opaque)
 +static int coroutine_fn commit_run(Job *job, Error **errp)
  {
 -    CommitBlockJob *s = opaque;
 +    CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
      CommitCompleteData *data;
      int64_t offset;
      uint64_t delay_ns = 0;
 @@ -XXX,XX +XXX,XX @@ out:
+     data = g_malloc(sizeof(*data));
+     data->ret = ret;
+     job_defer_to_main_loop(&s->common.job, commit_complete, data);
++    return ret;
+ }
+ static const BlockJobDriver commit_job_driver = {
+@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_job_driver = {
+         .free          = block_job_free,
+         .user_resume   = block_job_user_resume,
+         .drain         = block_job_drain,
+-        .start         = commit_run,
++        .run           = commit_run,
+     },
+ };
+diff --git a/block/create.c b/block/create.c
+index XXXXXXX..XXXXXXX 100644
+--- a/block/create.c
++++ b/block/create.c
+@@ -XXX,XX +XXX,XX @@ static void blockdev_create_complete(Job *job, void *opaque)
+     job_completed(job, s->ret, s->err);
+ }
+-static void coroutine_fn blockdev_create_run(void *opaque)
++static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
+ {
+-    BlockdevCreateJob *s = opaque;
++    BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
+     job_progress_set_remaining(&s->common, 1);
+     s->ret = s->drv->bdrv_co_create(s->opts, &s->err);
+@@ -XXX,XX +XXX,XX @@ static void coroutine_fn blockdev_create_run(void *opaque)
+     qapi_free_BlockdevCreateOptions(s->opts);
+     job_defer_to_main_loop(&s->common, blockdev_create_complete, NULL);
++
++    return s->ret;
+ }
+ static const JobDriver blockdev_create_job_driver = {
+     .instance_size = sizeof(BlockdevCreateJob),
+     .job_type      = JOB_TYPE_CREATE,
+-    .start         = blockdev_create_run,
++    .run           = blockdev_create_run,
+ };
+ void qmp_blockdev_create(const char *job_id, BlockdevCreateOptions *options,
+diff --git a/block/mirror.c b/block/mirror.c
+index XXXXXXX..XXXXXXX 100644
+--- a/block/mirror.c
++++ b/block/mirror.c
+@@ -XXX,XX +XXX,XX @@ static int mirror_flush(MirrorBlockJob *s)
      return ret;
  }
--static void error_callback_bh(void *opaque)
+-static void coroutine_fn mirror_run(void *opaque)
--{
++static int coroutine_fn mirror_run(Job *job, Error **errp)
--    Coroutine *co = opaque;
+ {
--    qemu_coroutine_enter(co);
+-    MirrorBlockJob *s = opaque;
--}
++    MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
--
+     MirrorExitData *data;
- static int inject_error(BlockDriverState *bs, BlkdebugRule *rule)
+     BlockDriverState *bs = s->mirror_top_bs->backing->bs;
- {
+     BlockDriverState *target_bs = blk_bs(s->target);
-     BDRVBlkdebugState *s = bs->opaque;
+@@ -XXX,XX +XXX,XX @@ immediate_exit:
-@@ -XXX,XX +XXX,XX @@ static int inject_error(BlockDriverState *bs, BlkdebugRule *rule)
+     if (need_drain) {
          bdrv_drained_begin(bs);
      }
++
-     if (!immediately) {
+     job_defer_to_main_loop(&s->common.job, mirror_exit, data);
--        aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), error_callback_bh,
++    return ret;
--                                qemu_coroutine_self());
+ }
-+        aio_co_schedule(qemu_get_current_aio_context(), qemu_coroutine_self());
-         qemu_coroutine_yield();
+ static void mirror_complete(Job *job, Error **errp)
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver mirror_job_driver = {
          .free                   = block_job_free,
          .user_resume            = block_job_user_resume,
          .drain                  = block_job_drain,
 -        .start                  = mirror_run,
 +        .run                    = mirror_run,
          .pause                  = mirror_pause,
          .complete               = mirror_complete,
      },
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_active_job_driver = {
          .free                   = block_job_free,
          .user_resume            = block_job_user_resume,
          .drain                  = block_job_drain,
 -        .start                  = mirror_run,
 +        .run                    = mirror_run,
          .pause                  = mirror_pause,
          .complete               = mirror_complete,
      },
 diff --git a/block/stream.c b/block/stream.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/stream.c
 +++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@ out:
      g_free(data);
  }
 -static void coroutine_fn stream_run(void *opaque)
 +static int coroutine_fn stream_run(Job *job, Error **errp)
  {
 -    StreamBlockJob *s = opaque;
 +    StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
      StreamCompleteData *data;
      BlockBackend *blk = s->common.blk;
      BlockDriverState *bs = blk_bs(blk);
@@ -XXX,XX +XXX,XX @@ out:
      data = g_malloc(sizeof(*data));
      data->ret = ret;
      job_defer_to_main_loop(&s->common.job, stream_complete, data);
 +    return ret;
  }
  static const BlockJobDriver stream_job_driver = {
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver stream_job_driver = {
          .instance_size = sizeof(StreamBlockJob),
          .job_type      = JOB_TYPE_STREAM,
          .free          = block_job_free,
 -        .start         = stream_run,
 +        .run           = stream_run,
          .user_resume   = block_job_user_resume,
          .drain         = block_job_drain,
      },
 diff --git a/job.c b/job.c
 index XXXXXXX..XXXXXXX 100644
 --- a/job.c
 +++ b/job.c
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)
  {
      Job *job = opaque;
 -    assert(job && job->driver && job->driver->start);
 +    assert(job && job->driver && job->driver->run);
      job_pause_point(job);
 -    job->driver->start(job);
 +    job->ret = job->driver->run(job, NULL);
  }
  void job_start(Job *job)
  {
      assert(job && !job_started(job) && job->paused &&
 -           job->driver && job->driver->start);
 +           job->driver && job->driver->run);
      job->co = qemu_coroutine_create(job_co_entry, job);
      job->pause_count--;
      job->busy = true;
 diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
 index XXXXXXX..XXXXXXX 100644
 --- a/tests/test-bdrv-drain.c
 +++ b/tests/test-bdrv-drain.c
@@ -XXX,XX +XXX,XX @@ static void test_job_completed(Job *job, void *opaque)
      job_completed(job, 0, NULL);
  }
 -static void coroutine_fn test_job_start(void *opaque)
 +static int coroutine_fn test_job_run(Job *job, Error **errp)
  {
 -    TestBlockJob *s = opaque;
 +    TestBlockJob *s = container_of(job, TestBlockJob, common.job);
      job_transition_to_ready(&s->common.job);
      while (!s->should_complete) {
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn test_job_start(void *opaque)
      }
+     job_defer_to_main_loop(&s->common.job, test_job_completed, NULL);
++    return 0;
+ }
+ static void test_job_complete(Job *job, Error **errp)
+@@ -XXX,XX +XXX,XX @@ BlockJobDriver test_job_driver = {
+         .free           = block_job_free,
+         .user_resume    = block_job_user_resume,
+         .drain          = block_job_drain,
+-        .start          = test_job_start,
++        .run            = test_job_run,
+         .complete       = test_job_complete,
+     },
+ };
+diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
+index XXXXXXX..XXXXXXX 100644
+--- a/tests/test-blockjob-txn.c
++++ b/tests/test-blockjob-txn.c
+@@ -XXX,XX +XXX,XX @@ static void test_block_job_complete(Job *job, void *opaque)
+     bdrv_unref(bs);
+ }
+-static void coroutine_fn test_block_job_run(void *opaque)
++static int coroutine_fn test_block_job_run(Job *job, Error **errp)
+ {
+-    TestBlockJob *s = opaque;
+-    BlockJob *job = &s->common;
++    TestBlockJob *s = container_of(job, TestBlockJob, common.job);
+     while (s->iterations--) {
+         if (s->use_timer) {
+-            job_sleep_ns(&job->job, 0);
++            job_sleep_ns(job, 0);
+         } else {
+-            job_yield(&job->job);
++            job_yield(job);
+         }
+-        if (job_is_cancelled(&job->job)) {
++        if (job_is_cancelled(job)) {
+             break;
+         }
+     }
+-    job_defer_to_main_loop(&job->job, test_block_job_complete,
++    job_defer_to_main_loop(job, test_block_job_complete,
+                            (void *)(intptr_t)s->rc);
++    return s->rc;
+ }
+ typedef struct {
+@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_block_job_driver = {
+         .free          = block_job_free,
+         .user_resume   = block_job_user_resume,
+         .drain         = block_job_drain,
+-        .start         = test_block_job_run,
++        .run           = test_block_job_run,
+     },
+ };
+diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
+index XXXXXXX..XXXXXXX 100644
+--- a/tests/test-blockjob.c
++++ b/tests/test-blockjob.c
+@@ -XXX,XX +XXX,XX @@ static void cancel_job_complete(Job *job, Error **errp)
+     s->should_complete = true;
+ }
+-static void coroutine_fn cancel_job_start(void *opaque)
++static int coroutine_fn cancel_job_run(Job *job, Error **errp)
+ {
+-    CancelJob *s = opaque;
++    CancelJob *s = container_of(job, CancelJob, common.job);
+     while (!s->should_complete) {
+         if (job_is_cancelled(&s->common.job)) {
+@@ -XXX,XX +XXX,XX @@ static void coroutine_fn cancel_job_start(void *opaque)
+  defer:
+     job_defer_to_main_loop(&s->common.job, cancel_job_completed, s);
++    return 0;
+ }
+ static const BlockJobDriver test_cancel_driver = {
+@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_cancel_driver = {
+         .free          = block_job_free,
+         .user_resume   = block_job_user_resume,
+         .drain         = block_job_drain,
+-        .start         = cancel_job_start,
++        .run           = cancel_job_run,
+         .complete      = cancel_job_complete,
+     },
+ };
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 23/24] coroutine-lock: add mutex argument to CoQueue APIs
+[Qemu-devel] [PULL v2 03/10] jobs: canonize Error object
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: John Snow <jsnow@redhat.com>
-All that CoQueue needs in order to become thread-safe is help
+Jobs presently use both an Error object in the case of the create job,
-from an external mutex.  Add this to the API.
+and char strings in the case of generic errors elsewhere.
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+Unify the two paths as just j->err, and remove the extra argument from
-Reviewed-by: Fam Zheng <famz@redhat.com>
+job_completed. The integer error code for job_completed is kept for now,
-Message-id: 20170213181244.16297-6-pbonzini@redhat.com
+to be removed shortly in a separate patch.
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 Signed-off-by: John Snow <jsnow@redhat.com>
 Message-id: 20180830015734.19765-3-jsnow@redhat.com
 [mreitz: Dropped a superfluous g_strdup()]
 Reviewed-by: Eric Blake <eblake@redhat.com>
 Signed-off-by: Max Reitz <mreitz@redhat.com>
 ---
- include/qemu/coroutine.h   |  8 +++++---
+ include/qemu/job.h        | 14 ++++++++------
- block/backup.c             |  2 +-
+ block/backup.c            |  2 +-
- block/io.c                 |  4 ++--
+ block/commit.c            |  2 +-
- block/nbd-client.c         |  2 +-
+ block/create.c            |  5 ++---
- block/qcow2-cluster.c      |  4 +---
+ block/mirror.c            |  2 +-
- block/sheepdog.c           |  2 +-
+ block/stream.c            |  2 +-
- block/throttle-groups.c    |  2 +-
+ job-qmp.c                 |  5 +++--
- hw/9pfs/9p.c               |  2 +-
+ job.c                     | 18 ++++++------------
- util/qemu-coroutine-lock.c | 24 +++++++++++++++++++++---
+ tests/test-bdrv-drain.c   |  2 +-
-files changed, 34 insertions(+), 16 deletions(-)
+ tests/test-blockjob-txn.c |  2 +-
+ tests/test-blockjob.c     |  2 +-
-diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
+files changed, 26 insertions(+), 30 deletions(-)
-index XXXXXXX..XXXXXXX 100644
---- a/include/qemu/coroutine.h
+diff --git a/include/qemu/job.h b/include/qemu/job.h
-+++ b/include/qemu/coroutine.h
+index XXXXXXX..XXXXXXX 100644
-@@ -XXX,XX +XXX,XX @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
+--- a/include/qemu/job.h
++++ b/include/qemu/job.h
@@ -XXX,XX +XXX,XX @@ typedef struct Job {
      /** Estimated progress_current value at the completion of the job */
      int64_t progress_total;
 -    /** Error string for a failed job (NULL if, and only if, job->ret == 0) */
 -    char *error;
 -
      /** ret code passed to job_completed. */
      int ret;
 +    /**
 +     * Error object for a failed job.
 +     * If job->ret is nonzero and an error object was not set, it will be set
 +     * to strerror(-job->ret) during job_completed.
 +     */
 +    Error *err;
 +
      /** The completion function that will be called when the job completes.  */
      BlockCompletionFunc *cb;
@@ -XXX,XX +XXX,XX @@ void job_transition_to_ready(Job *job);
  /**
-  * CoQueues are a mechanism to queue coroutines in order to continue executing
+  * @job: The job being completed.
-- * them later.
+  * @ret: The status code.
-+ * them later.  They are similar to condition variables, but they need help
+- * @error: The error message for a failing job (only with @ret < 0). If @ret is
-+ * from an external mutex in order to maintain thread-safety.
+- *         negative, but NULL is given for @error, strerror() is used.
   *
   * Marks @job as completed. If @ret is non-zero, the job transaction it is part
   * of is aborted. If @ret is zero, the job moves into the WAITING state. If it
   * is the last job to complete in its transaction, all jobs in the transaction
   * move from WAITING to PENDING.
   */
- typedef struct CoQueue {
+-void job_completed(Job *job, int ret, Error *error);
-     QSIMPLEQ_HEAD(, Coroutine) entries;
++void job_completed(Job *job, int ret);
-@@ -XXX,XX +XXX,XX @@ void qemu_co_queue_init(CoQueue *queue);
+ /** Asynchronously complete the specified @job. */
- /**
+ void job_complete(Job *job, Error **errp);
   * Adds the current coroutine to the CoQueue and transfers control to the
 - * caller of the coroutine.
 + * caller of the coroutine.  The mutex is unlocked during the wait and
 + * locked again afterwards.
   */
 -void coroutine_fn qemu_co_queue_wait(CoQueue *queue);
 +void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex);
  /**
   * Restarts the next coroutine in the CoQueue and removes it from the queue.
 diff --git a/block/backup.c b/block/backup.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/backup.c
 +++ b/block/backup.c
-@@ -XXX,XX +XXX,XX @@ static void coroutine_fn wait_for_overlapping_requests(BackupBlockJob *job,
+@@ -XXX,XX +XXX,XX @@ static void backup_complete(Job *job, void *opaque)
-         retry = false;
+ {
-         QLIST_FOREACH(req, &job->inflight_reqs, list) {
+     BackupCompleteData *data = opaque;
-             if (end > req->start && start < req->end) {
--                qemu_co_queue_wait(&req->wait_queue);
+-    job_completed(job, data->ret, NULL);
-+                qemu_co_queue_wait(&req->wait_queue, NULL);
++    job_completed(job, data->ret);
-                 retry = true;
+     g_free(data);
-                 break;
+ }
-             }
-diff --git a/block/io.c b/block/io.c
+diff --git a/block/commit.c b/block/commit.c
 index XXXXXXX..XXXXXXX 100644
---- a/block/io.c
+--- a/block/commit.c
-+++ b/block/io.c
++++ b/block/commit.c
-@@ -XXX,XX +XXX,XX @@ static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self)
+@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
-                  * (instead of producing a deadlock in the former case). */
+      * bdrv_set_backing_hd() to fail. */
-                 if (!req->waiting_for) {
+     block_job_remove_all_bdrv(bjob);
-                     self->waiting_for = req;
--                    qemu_co_queue_wait(&req->wait_queue);
+-    job_completed(job, ret, NULL);
-+                    qemu_co_queue_wait(&req->wait_queue, NULL);
++    job_completed(job, ret);
-                     self->waiting_for = NULL;
+     g_free(data);
-                     retry = true;
-                     waited = true;
+     /* If bdrv_drop_intermediate() didn't already do that, remove the commit
-@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
+diff --git a/block/create.c b/block/create.c
+index XXXXXXX..XXXXXXX 100644
-     /* Wait until any previous flushes are completed */
+--- a/block/create.c
-     while (bs->active_flush_req) {
++++ b/block/create.c
--        qemu_co_queue_wait(&bs->flush_queue);
+@@ -XXX,XX +XXX,XX @@ typedef struct BlockdevCreateJob {
-+        qemu_co_queue_wait(&bs->flush_queue, NULL);
+     BlockDriver *drv;
-     }
+     BlockdevCreateOptions *opts;
+     int ret;
-     bs->active_flush_req = true;
+-    Error *err;
-diff --git a/block/nbd-client.c b/block/nbd-client.c
+ } BlockdevCreateJob;
-index XXXXXXX..XXXXXXX 100644
---- a/block/nbd-client.c
+ static void blockdev_create_complete(Job *job, void *opaque)
-+++ b/block/nbd-client.c
+ {
-@@ -XXX,XX +XXX,XX @@ static void nbd_coroutine_start(NBDClientSession *s,
+     BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
-     /* Poor man semaphore.  The free_sema is locked when no other request
-      * can be accepted, and unlocked after receiving one reply.  */
+-    job_completed(job, s->ret, s->err);
-     if (s->in_flight == MAX_NBD_REQUESTS) {
++    job_completed(job, s->ret);
--        qemu_co_queue_wait(&s->free_sema);
+ }
-+        qemu_co_queue_wait(&s->free_sema, NULL);
-         assert(s->in_flight < MAX_NBD_REQUESTS);
+ static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
-     }
+@@ -XXX,XX +XXX,XX @@ static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
-     s->in_flight++;
+     BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
-diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
-index XXXXXXX..XXXXXXX 100644
+     job_progress_set_remaining(&s->common, 1);
---- a/block/qcow2-cluster.c
+-    s->ret = s->drv->bdrv_co_create(s->opts, &s->err);
-+++ b/block/qcow2-cluster.c
++    s->ret = s->drv->bdrv_co_create(s->opts, errp);
-@@ -XXX,XX +XXX,XX @@ static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset,
+     job_progress_update(&s->common, 1);
-             if (bytes == 0) {
-                 /* Wait for the dependency to complete. We need to recheck
+     qapi_free_BlockdevCreateOptions(s->opts);
-                  * the free/allocated clusters when we continue. */
+diff --git a/block/mirror.c b/block/mirror.c
--                qemu_co_mutex_unlock(&s->lock);
+index XXXXXXX..XXXXXXX 100644
--                qemu_co_queue_wait(&old_alloc->dependent_requests);
+--- a/block/mirror.c
--                qemu_co_mutex_lock(&s->lock);
++++ b/block/mirror.c
-+                qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock);
+@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
-                 return -EAGAIN;
+     blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort);
-             }
      bs_opaque->job = NULL;
 -    job_completed(job, data->ret, NULL);
 +    job_completed(job, data->ret);
      g_free(data);
      bdrv_drained_end(src);
 diff --git a/block/stream.c b/block/stream.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/stream.c
 +++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@ out:
      }
      g_free(s->backing_file_str);
 -    job_completed(job, data->ret, NULL);
 +    job_completed(job, data->ret);
      g_free(data);
  }
 diff --git a/job-qmp.c b/job-qmp.c
 index XXXXXXX..XXXXXXX 100644
 --- a/job-qmp.c
 +++ b/job-qmp.c
@@ -XXX,XX +XXX,XX @@ static JobInfo *job_query_single(Job *job, Error **errp)
          .status             = job->status,
          .current_progress   = job->progress_current,
          .total_progress     = job->progress_total,
 -        .has_error          = !!job->error,
 -        .error              = g_strdup(job->error),
 +        .has_error          = !!job->err,
 +        .error              = job->err ? \
 +                              g_strdup(error_get_pretty(job->err)) : NULL,
      };
      return info;
 diff --git a/job.c b/job.c
 index XXXXXXX..XXXXXXX 100644
 --- a/job.c
 +++ b/job.c
@@ -XXX,XX +XXX,XX @@ void job_unref(Job *job)
          QLIST_REMOVE(job, job_list);
 -        g_free(job->error);
 +        error_free(job->err);
          g_free(job->id);
          g_free(job);
      }
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)
      assert(job && job->driver && job->driver->run);
      job_pause_point(job);
 -    job->ret = job->driver->run(job, NULL);
 +    job->ret = job->driver->run(job, &job->err);
  }
@@ -XXX,XX +XXX,XX @@ static void job_update_rc(Job *job)
          job->ret = -ECANCELED;
      }
      if (job->ret) {
 -        if (!job->error) {
 -            job->error = g_strdup(strerror(-job->ret));
 +        if (!job->err) {
 +            error_setg(&job->err, "%s", strerror(-job->ret));
          }
-diff --git a/block/sheepdog.c b/block/sheepdog.c
+         job_state_transition(job, JOB_STATUS_ABORTING);
-index XXXXXXX..XXXXXXX 100644
+     }
---- a/block/sheepdog.c
+@@ -XXX,XX +XXX,XX @@ static void job_completed_txn_success(Job *job)
-+++ b/block/sheepdog.c
+     }
-@@ -XXX,XX +XXX,XX @@ static void wait_for_overlapping_aiocb(BDRVSheepdogState *s, SheepdogAIOCB *acb)
+ }
- retry:
-     QLIST_FOREACH(cb, &s->inflight_aiocb_head, aiocb_siblings) {
+-void job_completed(Job *job, int ret, Error *error)
-         if (AIOCBOverlapping(acb, cb)) {
++void job_completed(Job *job, int ret)
--            qemu_co_queue_wait(&s->overlapping_queue);
+ {
-+            qemu_co_queue_wait(&s->overlapping_queue, NULL);
+     assert(job && job->txn && !job_is_completed(job));
-             goto retry;
-         }
+     job->ret = ret;
-     }
+-    if (error) {
-diff --git a/block/throttle-groups.c b/block/throttle-groups.c
+-        assert(job->ret < 0);
-index XXXXXXX..XXXXXXX 100644
+-        job->error = g_strdup(error_get_pretty(error));
---- a/block/throttle-groups.c
+-        error_free(error);
-+++ b/block/throttle-groups.c
+-    }
-@@ -XXX,XX +XXX,XX @@ void coroutine_fn throttle_group_co_io_limits_intercept(BlockBackend *blk,
+-
-     if (must_wait || blkp->pending_reqs[is_write]) {
+     job_update_rc(job);
-         blkp->pending_reqs[is_write]++;
+     trace_job_completed(job, ret, job->ret);
-         qemu_mutex_unlock(&tg->lock);
+     if (job->ret) {
--        qemu_co_queue_wait(&blkp->throttled_reqs[is_write]);
+@@ -XXX,XX +XXX,XX @@ void job_cancel(Job *job, bool force)
-+        qemu_co_queue_wait(&blkp->throttled_reqs[is_write], NULL);
+     }
-         qemu_mutex_lock(&tg->lock);
+     job_cancel_async(job, force);
-         blkp->pending_reqs[is_write]--;
+     if (!job_started(job)) {
-     }
+-        job_completed(job, -ECANCELED, NULL);
-diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
++        job_completed(job, -ECANCELED);
-index XXXXXXX..XXXXXXX 100644
+     } else if (job->deferred_to_main_loop) {
---- a/hw/9pfs/9p.c
+         job_completed_txn_abort(job);
-+++ b/hw/9pfs/9p.c
+     } else {
-@@ -XXX,XX +XXX,XX @@ static void coroutine_fn v9fs_flush(void *opaque)
+diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
-         /*
+index XXXXXXX..XXXXXXX 100644
-          * Wait for pdu to complete.
+--- a/tests/test-bdrv-drain.c
-          */
++++ b/tests/test-bdrv-drain.c
--        qemu_co_queue_wait(&cancel_pdu->complete);
+@@ -XXX,XX +XXX,XX @@ typedef struct TestBlockJob {
-+        qemu_co_queue_wait(&cancel_pdu->complete, NULL);
-         cancel_pdu->cancelled = 0;
+ static void test_job_completed(Job *job, void *opaque)
-         pdu_free(cancel_pdu);
+ {
-     }
+-    job_completed(job, 0, NULL);
-diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
++    job_completed(job, 0);
-index XXXXXXX..XXXXXXX 100644
+ }
---- a/util/qemu-coroutine-lock.c
-+++ b/util/qemu-coroutine-lock.c
+ static int coroutine_fn test_job_run(Job *job, Error **errp)
-@@ -XXX,XX +XXX,XX @@ void qemu_co_queue_init(CoQueue *queue)
+diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
-     QSIMPLEQ_INIT(&queue->entries);
+index XXXXXXX..XXXXXXX 100644
- }
+--- a/tests/test-blockjob-txn.c
++++ b/tests/test-blockjob-txn.c
--void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
+@@ -XXX,XX +XXX,XX @@ static void test_block_job_complete(Job *job, void *opaque)
-+void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex)
+         rc = -ECANCELED;
- {
+     }
-     Coroutine *self = qemu_coroutine_self();
-     QSIMPLEQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
+-    job_completed(job, rc, NULL);
-+
++    job_completed(job, rc);
-+    if (mutex) {
+     bdrv_unref(bs);
-+        qemu_co_mutex_unlock(mutex);
+ }
-+    }
-+
+diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
-+    /* There is no race condition here.  Other threads will call
+index XXXXXXX..XXXXXXX 100644
-+     * aio_co_schedule on our AioContext, which can reenter this
+--- a/tests/test-blockjob.c
-+     * coroutine but only after this yield and after the main loop
++++ b/tests/test-blockjob.c
-+     * has gone through the next iteration.
+@@ -XXX,XX +XXX,XX @@ static void cancel_job_completed(Job *job, void *opaque)
-+     */
+ {
-     qemu_coroutine_yield();
+     CancelJob *s = opaque;
-     assert(qemu_in_coroutine());
+     s->completed = true;
-+
+-    job_completed(job, 0, NULL);
-+    /* TODO: OSv implements wait morphing here, where the wakeup
++    job_completed(job, 0);
-+     * primitive automatically places the woken coroutine on the
+ }
-+     * mutex's queue.  This avoids the thundering herd effect.
-+     */
+ static void cancel_job_complete(Job *job, Error **errp)
 +    if (mutex) {
 +        qemu_co_mutex_lock(mutex);
 +    }
  }
  /**
@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_rdlock(CoRwlock *lock)
      Coroutine *self = qemu_coroutine_self();
      while (lock->writer) {
 -        qemu_co_queue_wait(&lock->queue);
 +        qemu_co_queue_wait(&lock->queue, NULL);
      }
      lock->reader++;
      self->locks_held++;
@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_wrlock(CoRwlock *lock)
      Coroutine *self = qemu_coroutine_self();
      while (lock->writer || lock->reader) {
 -        qemu_co_queue_wait(&lock->queue);
 +        qemu_co_queue_wait(&lock->queue, NULL);
      }
      lock->writer = true;
      self->locks_held++;
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 10/24] qed: introduce qed_aio_start_io and qed_aio_next_io_cb
+[Qemu-devel] [PULL v2 04/10] jobs: add exit shim
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: John Snow <jsnow@redhat.com>
-qed_aio_start_io and qed_aio_next_io will not have to acquire/release
+All jobs do the same thing when they leave their running loop:
-the AioContext, while qed_aio_next_io_cb will.  Split the functionality
+- Store the return code in a structure
-and gain a little type-safety in the process.
+- wait to receive this structure in the main thread
 - signal job completion via job_completed
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Few jobs do anything beyond exactly this. Consolidate this exit
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+logic for a net reduction in SLOC.
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
+More seriously, when we utilize job_defer_to_main_loop_bh to call
-Message-id: 20170213135235.12274-11-pbonzini@redhat.com
+a function that calls job_completed, job_finalize_single will run
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+in a context where it has recursively taken the aio_context lock,
 which can cause hangs if it puts down a reference that causes a flush.
 You can observe this in practice by looking at mirror_exit's careful
 placement of job_completed and bdrv_unref calls.
 If we centralize job exiting, we can signal job completion from outside
 of the aio_context, which should allow for job cleanup code to run with
 only one lock, which makes cleanup callbacks less tricky to write.
 Signed-off-by: John Snow <jsnow@redhat.com>
 Reviewed-by: Max Reitz <mreitz@redhat.com>
 Message-id: 20180830015734.19765-4-jsnow@redhat.com
 Reviewed-by: Jeff Cody <jcody@redhat.com>
 Signed-off-by: Max Reitz <mreitz@redhat.com>
 ---
- block/qed.c | 39 +++++++++++++++++++++++++--------------
+ include/qemu/job.h | 11 +++++++++++
-file changed, 25 insertions(+), 14 deletions(-)
+ job.c              | 18 ++++++++++++++++++
 files changed, 29 insertions(+)
-diff --git a/block/qed.c b/block/qed.c
+diff --git a/include/qemu/job.h b/include/qemu/job.h
 index XXXXXXX..XXXXXXX 100644
---- a/block/qed.c
+--- a/include/qemu/job.h
-+++ b/block/qed.c
++++ b/include/qemu/job.h
-@@ -XXX,XX +XXX,XX @@ static CachedL2Table *qed_new_l2_table(BDRVQEDState *s)
+@@ -XXX,XX +XXX,XX @@ struct JobDriver {
-     return l2_table;
+      */
- }
+     void (*drain)(Job *job);
--static void qed_aio_next_io(void *opaque, int ret);
++    /**
-+static void qed_aio_next_io(QEDAIOCB *acb, int ret);
++     * If the callback is not NULL, exit will be invoked from the main thread
 +     * when the job's coroutine has finished, but before transactional
 +     * convergence; before @prepare or @abort.
 +     *
 +     * FIXME TODO: This callback is only temporary to transition remaining jobs
 +     * to prepare/commit/abort/clean callbacks and will be removed before 3.1.
 +     * is released.
 +     */
 +    void (*exit)(Job *job);
 +
-+static void qed_aio_start_io(QEDAIOCB *acb)
+     /**
-+{
+      * If the callback is not NULL, prepare will be invoked when all the jobs
-+    qed_aio_next_io(acb, 0);
+      * belonging to the same transaction complete; or upon this job's completion
-+}
+diff --git a/job.c b/job.c
-+
+index XXXXXXX..XXXXXXX 100644
-+static void qed_aio_next_io_cb(void *opaque, int ret)
+--- a/job.c
-+{
++++ b/job.c
-+    QEDAIOCB *acb = opaque;
+@@ -XXX,XX +XXX,XX @@ void job_drain(Job *job)
 +
 +    qed_aio_next_io(acb, ret);
 +}
  static void qed_plug_allocating_write_reqs(BDRVQEDState *s)
  {
@@ -XXX,XX +XXX,XX @@ static void qed_unplug_allocating_write_reqs(BDRVQEDState *s)
      acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs);
      if (acb) {
 -        qed_aio_next_io(acb, 0);
 +        qed_aio_start_io(acb);
      }
  }
-@@ -XXX,XX +XXX,XX @@ static void qed_aio_complete(QEDAIOCB *acb, int ret)
++static void job_exit(void *opaque)
-         QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next);
++{
-         acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs);
++    Job *job = (Job *)opaque;
-         if (acb) {
++    AioContext *aio_context = job->aio_context;
--            qed_aio_next_io(acb, 0);
++
-+            qed_aio_start_io(acb);
++    if (job->driver->exit) {
-         } else if (s->header.features & QED_F_NEED_CHECK) {
++        aio_context_acquire(aio_context);
-             qed_start_need_check_timer(s);
++        job->driver->exit(job);
-         }
++        aio_context_release(aio_context);
-@@ -XXX,XX +XXX,XX @@ static void qed_commit_l2_update(void *opaque, int ret)
++    }
-     acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
++    job_completed(job, job->ret);
-     assert(acb->request.l2_table != NULL);
++}
--    qed_aio_next_io(opaque, ret);
+ /**
-+    qed_aio_next_io(acb, ret);
+  * All jobs must allow a pause point before entering their job proper. This
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)
      assert(job && job->driver && job->driver->run);
      job_pause_point(job);
      job->ret = job->driver->run(job, &job->err);
 +    if (!job->deferred_to_main_loop) {
 +        job->deferred_to_main_loop = true;
 +        aio_bh_schedule_oneshot(qemu_get_aio_context(),
 +                                job_exit,
 +                                job);
 +    }
  }
- /**
-@@ -XXX,XX +XXX,XX @@ static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset)
-     if (need_alloc) {
-         /* Write out the whole new L2 table */
-         qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true,
--                            qed_aio_write_l1_update, acb);
-+                           qed_aio_write_l1_update, acb);
-     } else {
-         /* Write out only the updated part of the L2 table */
-         qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false,
--                            qed_aio_next_io, acb);
-+                           qed_aio_next_io_cb, acb);
-     }
-     return;
-@@ -XXX,XX +XXX,XX @@ static void qed_aio_write_main(void *opaque, int ret)
-     }
-     if (acb->find_cluster_ret == QED_CLUSTER_FOUND) {
--        next_fn = qed_aio_next_io;
-+        next_fn = qed_aio_next_io_cb;
-     } else {
-         if (s->bs->backing) {
-             next_fn = qed_aio_write_flush_before_l2_update;
-@@ -XXX,XX +XXX,XX @@ static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len)
-     if (acb->flags & QED_AIOCB_ZERO) {
-         /* Skip ahead if the clusters are already zero */
-         if (acb->find_cluster_ret == QED_CLUSTER_ZERO) {
--            qed_aio_next_io(acb, 0);
-+            qed_aio_start_io(acb);
-             return;
-         }
-@@ -XXX,XX +XXX,XX @@ static void qed_aio_read_data(void *opaque, int ret,
-     /* Handle zero cluster and backing file reads */
-     if (ret == QED_CLUSTER_ZERO) {
-         qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size);
--        qed_aio_next_io(acb, 0);
-+        qed_aio_start_io(acb);
-         return;
-     } else if (ret != QED_CLUSTER_FOUND) {
-         qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov,
--                              &acb->backing_qiov, qed_aio_next_io, acb);
-+                              &acb->backing_qiov, qed_aio_next_io_cb, acb);
-         return;
-     }
-     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
-     bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE,
-                    &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE,
--                   qed_aio_next_io, acb);
-+                   qed_aio_next_io_cb, acb);
-     return;
- err:
-@@ -XXX,XX +XXX,XX @@ err:
- /**
-  * Begin next I/O or complete the request
-  */
--static void qed_aio_next_io(void *opaque, int ret)
-+static void qed_aio_next_io(QEDAIOCB *acb, int ret)
- {
--    QEDAIOCB *acb = opaque;
-     BDRVQEDState *s = acb_to_s(acb);
-     QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ?
-                                 qed_aio_write_data : qed_aio_read_data;
-@@ -XXX,XX +XXX,XX @@ static BlockAIOCB *qed_aio_setup(BlockDriverState *bs,
-     qemu_iovec_init(&acb->cur_qiov, qiov->niov);
-     /* Start request */
--    qed_aio_next_io(acb, 0);
-+    qed_aio_start_io(acb);
-     return &acb->common;
- }
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 06/24] io: make qio_channel_yield aware of AioContexts
+[Qemu-devel] [PULL v2 05/10] block/commit: utilize job_exit shim
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: John Snow <jsnow@redhat.com>
-Support separate coroutines for reading and writing, and place the
+Change the manual deferment to commit_complete into the implicit
-read/write handlers on the AioContext that the QIOChannel is registered
+callback to job_exit, renaming commit_complete to commit_exit.
 with.
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
+This conversion does change the timing of when job_completed is
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+called to after the bdrv_replace_node and bdrv_unref calls, which
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+could have implications for bjob->blk which will now be put down
-Reviewed-by: Fam Zheng <famz@redhat.com>
+after this cleanup.
-Message-id: 20170213135235.12274-7-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+Kevin highlights that we did not take any permissions for that backend
 at job creation time, so it is safe to reorder these operations.
 Signed-off-by: John Snow <jsnow@redhat.com>
 Reviewed-by: Max Reitz <mreitz@redhat.com>
 Message-id: 20180830015734.19765-5-jsnow@redhat.com
 Reviewed-by: Jeff Cody <jcody@redhat.com>
 Signed-off-by: Max Reitz <mreitz@redhat.com>
 ---
- include/io/channel.h | 47 ++++++++++++++++++++++++++--
+ block/commit.c | 22 +++++-----------------
- io/channel.c         | 86 +++++++++++++++++++++++++++++++++++++++-------------
+file changed, 5 insertions(+), 17 deletions(-)
 files changed, 109 insertions(+), 24 deletions(-)
-diff --git a/include/io/channel.h b/include/io/channel.h
+diff --git a/block/commit.c b/block/commit.c
 index XXXXXXX..XXXXXXX 100644
---- a/include/io/channel.h
+--- a/block/commit.c
-+++ b/include/io/channel.h
++++ b/block/commit.c
-@@ -XXX,XX +XXX,XX @@
+@@ -XXX,XX +XXX,XX @@ static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,
+     return 0;
  #include "qemu-common.h"
  #include "qom/object.h"
 +#include "qemu/coroutine.h"
  #include "block/aio.h"
  #define TYPE_QIO_CHANNEL "qio-channel"
@@ -XXX,XX +XXX,XX @@ struct QIOChannel {
      Object parent;
      unsigned int features; /* bitmask of QIOChannelFeatures */
      char *name;
 +    AioContext *ctx;
 +    Coroutine *read_coroutine;
 +    Coroutine *write_coroutine;
  #ifdef _WIN32
      HANDLE event; /* For use with GSource on Win32 */
  #endif
@@ -XXX,XX +XXX,XX @@ guint qio_channel_add_watch(QIOChannel *ioc,
  /**
 + * qio_channel_attach_aio_context:
 + * @ioc: the channel object
 + * @ctx: the #AioContext to set the handlers on
 + *
 + * Request that qio_channel_yield() sets I/O handlers on
 + * the given #AioContext.  If @ctx is %NULL, qio_channel_yield()
 + * uses QEMU's main thread event loop.
 + *
 + * You can move a #QIOChannel from one #AioContext to another even if
 + * I/O handlers are set for a coroutine.  However, #QIOChannel provides
 + * no synchronization between the calls to qio_channel_yield() and
 + * qio_channel_attach_aio_context().
 + *
 + * Therefore you should first call qio_channel_detach_aio_context()
 + * to ensure that the coroutine is not entered concurrently.  Then,
 + * while the coroutine has yielded, call qio_channel_attach_aio_context(),
 + * and then aio_co_schedule() to place the coroutine on the new
 + * #AioContext.  The calls to qio_channel_detach_aio_context()
 + * and qio_channel_attach_aio_context() should be protected with
 + * aio_context_acquire() and aio_context_release().
 + */
 +void qio_channel_attach_aio_context(QIOChannel *ioc,
 +                                    AioContext *ctx);
 +
 +/**
 + * qio_channel_detach_aio_context:
 + * @ioc: the channel object
 + *
 + * Disable any I/O handlers set by qio_channel_yield().  With the
 + * help of aio_co_schedule(), this allows moving a coroutine that was
 + * paused by qio_channel_yield() to another context.
 + */
 +void qio_channel_detach_aio_context(QIOChannel *ioc);
 +
 +/**
   * qio_channel_yield:
   * @ioc: the channel object
   * @condition: the I/O condition to wait for
   *
 - * Yields execution from the current coroutine until
 - * the condition indicated by @condition becomes
 - * available.
 + * Yields execution from the current coroutine until the condition
 + * indicated by @condition becomes available.  @condition must
 + * be either %G_IO_IN or %G_IO_OUT; it cannot contain both.  In
 + * addition, no two coroutine can be waiting on the same condition
 + * and channel at the same time.
   *
   * This must only be called from coroutine context
   */
 diff --git a/io/channel.c b/io/channel.c
 index XXXXXXX..XXXXXXX 100644
 --- a/io/channel.c
 +++ b/io/channel.c
@@ -XXX,XX +XXX,XX @@
  #include "qemu/osdep.h"
  #include "io/channel.h"
  #include "qapi/error.h"
 -#include "qemu/coroutine.h"
 +#include "qemu/main-loop.h"
  bool qio_channel_has_feature(QIOChannel *ioc,
                               QIOChannelFeature feature)
@@ -XXX,XX +XXX,XX @@ off_t qio_channel_io_seek(QIOChannel *ioc,
  }
+-typedef struct {
--typedef struct QIOChannelYieldData QIOChannelYieldData;
+-    int ret;
--struct QIOChannelYieldData {
+-} CommitCompleteData;
--    QIOChannel *ioc;
+-
--    Coroutine *co;
+-static void commit_complete(Job *job, void *opaque)
--};
++static void commit_exit(Job *job)
 +static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc);
 +static void qio_channel_restart_read(void *opaque)
 +{
 +    QIOChannel *ioc = opaque;
 +    Coroutine *co = ioc->read_coroutine;
 +
 +    ioc->read_coroutine = NULL;
 +    qio_channel_set_aio_fd_handlers(ioc);
 +    aio_co_wake(co);
 +}
 -static gboolean qio_channel_yield_enter(QIOChannel *ioc,
 -                                        GIOCondition condition,
 -                                        gpointer opaque)
 +static void qio_channel_restart_write(void *opaque)
  {
--    QIOChannelYieldData *data = opaque;
+     CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
--    qemu_coroutine_enter(data->co);
+     BlockJob *bjob = &s->common;
--    return FALSE;
+-    CommitCompleteData *data = opaque;
-+    QIOChannel *ioc = opaque;
+     BlockDriverState *top = blk_bs(s->top);
-+    Coroutine *co = ioc->write_coroutine;
+     BlockDriverState *base = blk_bs(s->base);
-+
+     BlockDriverState *commit_top_bs = s->commit_top_bs;
-+    ioc->write_coroutine = NULL;
+-    int ret = data->ret;
-+    qio_channel_set_aio_fd_handlers(ioc);
+     bool remove_commit_top_bs = false;
-+    aio_co_wake(co);
      /* Make sure commit_top_bs and top stay around until bdrv_replace_node() */
@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
       * the normal backing chain can be restored. */
      blk_unref(s->base);
 -    if (!job_is_cancelled(job) && ret == 0) {
 +    if (!job_is_cancelled(job) && job->ret == 0) {
          /* success */
 -        ret = bdrv_drop_intermediate(s->commit_top_bs, base,
 -                                     s->backing_file_str);
 +        job->ret = bdrv_drop_intermediate(s->commit_top_bs, base,
 +                                          s->backing_file_str);
      } else {
          /* XXX Can (or should) we somehow keep 'consistent read' blocked even
           * after the failed/cancelled commit job is gone? If we already wrote
@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
       * bdrv_set_backing_hd() to fail. */
      block_job_remove_all_bdrv(bjob);
 -    job_completed(job, ret);
 -    g_free(data);
 -
      /* If bdrv_drop_intermediate() didn't already do that, remove the commit
       * filter driver from the backing chain. Do this as the final step so that
       * the 'consistent read' permission can be granted.  */
@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
  static int coroutine_fn commit_run(Job *job, Error **errp)
  {
      CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
 -    CommitCompleteData *data;
      int64_t offset;
      uint64_t delay_ns = 0;
      int ret = 0;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn commit_run(Job *job, Error **errp)
  out:
      qemu_vfree(buf);
 -    data = g_malloc(sizeof(*data));
 -    data->ret = ret;
 -    job_defer_to_main_loop(&s->common.job, commit_complete, data);
      return ret;
  }
-+static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc)
+@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_job_driver = {
-+{
+         .user_resume   = block_job_user_resume,
-+    IOHandler *rd_handler = NULL, *wr_handler = NULL;
+         .drain         = block_job_drain,
-+    AioContext *ctx;
+         .run           = commit_run,
-+
++        .exit          = commit_exit,
-+    if (ioc->read_coroutine) {
+     },
-+        rd_handler = qio_channel_restart_read;
+ };
 +    }
 +    if (ioc->write_coroutine) {
 +        wr_handler = qio_channel_restart_write;
 +    }
 +
 +    ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
 +    qio_channel_set_aio_fd_handler(ioc, ctx, rd_handler, wr_handler, ioc);
 +}
 +
 +void qio_channel_attach_aio_context(QIOChannel *ioc,
 +                                    AioContext *ctx)
 +{
 +    AioContext *old_ctx;
 +    if (ioc->ctx == ctx) {
 +        return;
 +    }
 +
 +    old_ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
 +    qio_channel_set_aio_fd_handler(ioc, old_ctx, NULL, NULL, NULL);
 +    ioc->ctx = ctx;
 +    qio_channel_set_aio_fd_handlers(ioc);
 +}
 +
 +void qio_channel_detach_aio_context(QIOChannel *ioc)
 +{
 +    ioc->read_coroutine = NULL;
 +    ioc->write_coroutine = NULL;
 +    qio_channel_set_aio_fd_handlers(ioc);
 +    ioc->ctx = NULL;
 +}
  void coroutine_fn qio_channel_yield(QIOChannel *ioc,
                                      GIOCondition condition)
  {
 -    QIOChannelYieldData data;
 -
      assert(qemu_in_coroutine());
 -    data.ioc = ioc;
 -    data.co = qemu_coroutine_self();
 -    qio_channel_add_watch(ioc,
 -                          condition,
 -                          qio_channel_yield_enter,
 -                          &data,
 -                          NULL);
 +    if (condition == G_IO_IN) {
 +        assert(!ioc->read_coroutine);
 +        ioc->read_coroutine = qemu_coroutine_self();
 +    } else if (condition == G_IO_OUT) {
 +        assert(!ioc->write_coroutine);
 +        ioc->write_coroutine = qemu_coroutine_self();
 +    } else {
 +        abort();
 +    }
 +    qio_channel_set_aio_fd_handlers(ioc);
      qemu_coroutine_yield();
  }
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 15/24] block: explicitly acquire aiocontext in aio callbacks that need it
+[Qemu-devel] [PULL v2 06/10] block/mirror: utilize job_exit shim
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: John Snow <jsnow@redhat.com>
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Change the manual deferment to mirror_exit into the implicit
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+callback to job_exit and the mirror_exit callback.
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
+This does change the order of some bdrv_unref calls and job_completed,
-Message-id: 20170213135235.12274-16-pbonzini@redhat.com
+but thanks to the new context in which we call .exit, this is safe to
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
+defer the possible flushing of any nodes to the job_finalize_single
 cleanup stage.
 Signed-off-by: John Snow <jsnow@redhat.com>
 Message-id: 20180830015734.19765-6-jsnow@redhat.com
 Reviewed-by: Max Reitz <mreitz@redhat.com>
 Reviewed-by: Jeff Cody <jcody@redhat.com>
 Signed-off-by: Max Reitz <mreitz@redhat.com>
 ---
- block/archipelago.c    |  3 ---
+ block/mirror.c | 29 +++++++++++------------------
- block/block-backend.c  |  7 -------
+file changed, 11 insertions(+), 18 deletions(-)
  block/curl.c           |  2 +-
  block/io.c             |  6 +-----
  block/iscsi.c          |  3 ---
  block/linux-aio.c      |  5 +----
  block/mirror.c         | 12 +++++++++---
  block/null.c           |  8 --------
  block/qed-cluster.c    |  2 ++
  block/qed-table.c      | 12 ++++++++++--
  block/qed.c            |  4 ++--
  block/rbd.c            |  4 ----
  block/win32-aio.c      |  3 ---
  hw/block/virtio-blk.c  | 12 +++++++++++-
  hw/scsi/scsi-disk.c    | 15 +++++++++++++++
  hw/scsi/scsi-generic.c | 20 +++++++++++++++++---
  util/thread-pool.c     |  4 +++-
 files changed, 72 insertions(+), 50 deletions(-)
-diff --git a/block/archipelago.c b/block/archipelago.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/archipelago.c
-+++ b/block/archipelago.c
-@@ -XXX,XX +XXX,XX @@ static void qemu_archipelago_complete_aio(void *opaque)
- {
-     AIORequestData *reqdata = (AIORequestData *) opaque;
-     ArchipelagoAIOCB *aio_cb = (ArchipelagoAIOCB *) reqdata->aio_cb;
--    AioContext *ctx = bdrv_get_aio_context(aio_cb->common.bs);
--    aio_context_acquire(ctx);
-     aio_cb->common.cb(aio_cb->common.opaque, aio_cb->ret);
--    aio_context_release(ctx);
-     aio_cb->status = 0;
-     qemu_aio_unref(aio_cb);
-diff --git a/block/block-backend.c b/block/block-backend.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/block-backend.c
-+++ b/block/block-backend.c
-@@ -XXX,XX +XXX,XX @@ int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags)
- static void error_callback_bh(void *opaque)
- {
-     struct BlockBackendAIOCB *acb = opaque;
--    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
-     bdrv_dec_in_flight(acb->common.bs);
--    aio_context_acquire(ctx);
-     acb->common.cb(acb->common.opaque, acb->ret);
--    aio_context_release(ctx);
-     qemu_aio_unref(acb);
- }
-@@ -XXX,XX +XXX,XX @@ static void blk_aio_complete(BlkAioEmAIOCB *acb)
- static void blk_aio_complete_bh(void *opaque)
- {
-     BlkAioEmAIOCB *acb = opaque;
--    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
--
-     assert(acb->has_returned);
--    aio_context_acquire(ctx);
-     blk_aio_complete(acb);
--    aio_context_release(ctx);
- }
- static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes,
-diff --git a/block/curl.c b/block/curl.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/curl.c
-+++ b/block/curl.c
-@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
-     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
- out:
-+    aio_context_release(ctx);
-     if (ret != -EINPROGRESS) {
-         acb->common.cb(acb->common.opaque, ret);
-         qemu_aio_unref(acb);
-     }
--    aio_context_release(ctx);
- }
- static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,
-diff --git a/block/io.c b/block/io.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/io.c
-+++ b/block/io.c
-@@ -XXX,XX +XXX,XX @@ static void bdrv_co_io_em_complete(void *opaque, int ret)
-     CoroutineIOCompletion *co = opaque;
-     co->ret = ret;
--    qemu_coroutine_enter(co->coroutine);
-+    aio_co_wake(co->coroutine);
- }
- static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
-@@ -XXX,XX +XXX,XX @@ static void bdrv_co_complete(BlockAIOCBCoroutine *acb)
- static void bdrv_co_em_bh(void *opaque)
- {
-     BlockAIOCBCoroutine *acb = opaque;
--    BlockDriverState *bs = acb->common.bs;
--    AioContext *ctx = bdrv_get_aio_context(bs);
-     assert(!acb->need_bh);
--    aio_context_acquire(ctx);
-     bdrv_co_complete(acb);
--    aio_context_release(ctx);
- }
- static void bdrv_co_maybe_schedule_bh(BlockAIOCBCoroutine *acb)
-diff --git a/block/iscsi.c b/block/iscsi.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/iscsi.c
-+++ b/block/iscsi.c
-@@ -XXX,XX +XXX,XX @@ static void
- iscsi_bh_cb(void *p)
- {
-     IscsiAIOCB *acb = p;
--    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
-     qemu_bh_delete(acb->bh);
-     g_free(acb->buf);
-     acb->buf = NULL;
--    aio_context_acquire(ctx);
-     acb->common.cb(acb->common.opaque, acb->status);
--    aio_context_release(ctx);
-     if (acb->task != NULL) {
-         scsi_free_scsi_task(acb->task);
-diff --git a/block/linux-aio.c b/block/linux-aio.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/linux-aio.c
-+++ b/block/linux-aio.c
-@@ -XXX,XX +XXX,XX @@ static inline ssize_t io_event_ret(struct io_event *ev)
-  */
- static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
- {
--    LinuxAioState *s = laiocb->ctx;
-     int ret;
-     ret = laiocb->ret;
-@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
-     }
-     laiocb->ret = ret;
--    aio_context_acquire(s->aio_context);
-     if (laiocb->co) {
-         /* If the coroutine is already entered it must be in ioq_submit() and
-          * will notice laio->ret has been filled in when it eventually runs
-@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
-          * that!
-          */
-         if (!qemu_coroutine_entered(laiocb->co)) {
--            qemu_coroutine_enter(laiocb->co);
-+            aio_co_wake(laiocb->co);
-         }
-     } else {
-         laiocb->common.cb(laiocb->common.opaque, ret);
-         qemu_aio_unref(laiocb);
-     }
--    aio_context_release(s->aio_context);
- }
- /**
 diff --git a/block/mirror.c b/block/mirror.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/mirror.c
 +++ b/block/mirror.c
-@@ -XXX,XX +XXX,XX @@ static void mirror_write_complete(void *opaque, int ret)
+@@ -XXX,XX +XXX,XX @@ static void mirror_wait_for_all_io(MirrorBlockJob *s)
      }
  }
 -typedef struct {
 -    int ret;
 -} MirrorExitData;
 -
 -static void mirror_exit(Job *job, void *opaque)
 +static void mirror_exit(Job *job)
  {
-     MirrorOp *op = opaque;
+     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
-     MirrorBlockJob *s = op->s;
+     BlockJob *bjob = &s->common;
-+
+-    MirrorExitData *data = opaque;
-+    aio_context_acquire(blk_get_aio_context(s->common.blk));
+     MirrorBDSOpaque *bs_opaque = s->mirror_top_bs->opaque;
-     if (ret < 0) {
+     AioContext *replace_aio_context = NULL;
-         BlockErrorAction action;
+     BlockDriverState *src = s->mirror_top_bs->backing->bs;
+     BlockDriverState *target_bs = blk_bs(s->target);
-@@ -XXX,XX +XXX,XX @@ static void mirror_write_complete(void *opaque, int ret)
+     BlockDriverState *mirror_top_bs = s->mirror_top_bs;
      Error *local_err = NULL;
 +    int ret = job->ret;
      bdrv_release_dirty_bitmap(src, s->dirty_bitmap);
 -    /* Make sure that the source BDS doesn't go away before we called
 -     * job_completed(). */
 +    /* Make sure that the source BDS doesn't go away during bdrv_replace_node,
 +     * before we can call bdrv_drained_end */
      bdrv_ref(src);
      bdrv_ref(mirror_top_bs);
      bdrv_ref(target_bs);
@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
              bdrv_set_backing_hd(target_bs, backing, &local_err);
              if (local_err) {
                  error_report_err(local_err);
 -                data->ret = -EPERM;
 +                ret = -EPERM;
              }
          }
      }
-     mirror_iteration_done(op, ret);
+@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
-+    aio_context_release(blk_get_aio_context(s->common.blk));
+         aio_context_acquire(replace_aio_context);
  }
  static void mirror_read_complete(void *opaque, int ret)
  {
      MirrorOp *op = opaque;
      MirrorBlockJob *s = op->s;
 +
 +    aio_context_acquire(blk_get_aio_context(s->common.blk));
      if (ret < 0) {
          BlockErrorAction action;
@@ -XXX,XX +XXX,XX @@ static void mirror_read_complete(void *opaque, int ret)
          }
          mirror_iteration_done(op, ret);
 -        return;
 +    } else {
 +        blk_aio_pwritev(s->target, op->sector_num * BDRV_SECTOR_SIZE, &op->qiov,
 +                        0, mirror_write_complete, op);
      }
--    blk_aio_pwritev(s->target, op->sector_num * BDRV_SECTOR_SIZE, &op->qiov,
--                    0, mirror_write_complete, op);
+-    if (s->should_complete && data->ret == 0) {
-+    aio_context_release(blk_get_aio_context(s->common.blk));
++    if (s->should_complete && ret == 0) {
- }
+         BlockDriverState *to_replace = src;
+         if (s->to_replace) {
- static inline void mirror_clip_sectors(MirrorBlockJob *s,
+             to_replace = s->to_replace;
-diff --git a/block/null.c b/block/null.c
+@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
-index XXXXXXX..XXXXXXX 100644
+         bdrv_drained_end(target_bs);
---- a/block/null.c
+         if (local_err) {
-+++ b/block/null.c
+             error_report_err(local_err);
-@@ -XXX,XX +XXX,XX @@ static const AIOCBInfo null_aiocb_info = {
+-            data->ret = -EPERM;
- static void null_bh_cb(void *opaque)
++            ret = -EPERM;
  {
      NullAIOCB *acb = opaque;
 -    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
 -
 -    aio_context_acquire(ctx);
      acb->common.cb(acb->common.opaque, 0);
 -    aio_context_release(ctx);
      qemu_aio_unref(acb);
  }
  static void null_timer_cb(void *opaque)
  {
      NullAIOCB *acb = opaque;
 -    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
 -
 -    aio_context_acquire(ctx);
      acb->common.cb(acb->common.opaque, 0);
 -    aio_context_release(ctx);
      timer_deinit(&acb->timer);
      qemu_aio_unref(acb);
  }
 diff --git a/block/qed-cluster.c b/block/qed-cluster.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/qed-cluster.c
 +++ b/block/qed-cluster.c
@@ -XXX,XX +XXX,XX @@ static void qed_find_cluster_cb(void *opaque, int ret)
      unsigned int index;
      unsigned int n;
 +    qed_acquire(s);
      if (ret) {
          goto out;
      }
@@ -XXX,XX +XXX,XX @@ static void qed_find_cluster_cb(void *opaque, int ret)
  out:
      find_cluster_cb->cb(find_cluster_cb->opaque, ret, offset, len);
 +    qed_release(s);
      g_free(find_cluster_cb);
  }
 diff --git a/block/qed-table.c b/block/qed-table.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/qed-table.c
 +++ b/block/qed-table.c
@@ -XXX,XX +XXX,XX @@ static void qed_read_table_cb(void *opaque, int ret)
  {
      QEDReadTableCB *read_table_cb = opaque;
      QEDTable *table = read_table_cb->table;
 +    BDRVQEDState *s = read_table_cb->s;
      int noffsets = read_table_cb->qiov.size / sizeof(uint64_t);
      int i;
@@ -XXX,XX +XXX,XX @@ static void qed_read_table_cb(void *opaque, int ret)
      }
      /* Byteswap offsets */
 +    qed_acquire(s);
      for (i = 0; i < noffsets; i++) {
          table->offsets[i] = le64_to_cpu(table->offsets[i]);
      }
 +    qed_release(s);
  out:
      /* Completion */
 -    trace_qed_read_table_cb(read_table_cb->s, read_table_cb->table, ret);
 +    trace_qed_read_table_cb(s, read_table_cb->table, ret);
      gencb_complete(&read_table_cb->gencb, ret);
  }
@@ -XXX,XX +XXX,XX @@ typedef struct {
  static void qed_write_table_cb(void *opaque, int ret)
  {
      QEDWriteTableCB *write_table_cb = opaque;
 +    BDRVQEDState *s = write_table_cb->s;
 -    trace_qed_write_table_cb(write_table_cb->s,
 +    trace_qed_write_table_cb(s,
                               write_table_cb->orig_table,
                               write_table_cb->flush,
                               ret);
@@ -XXX,XX +XXX,XX @@ static void qed_write_table_cb(void *opaque, int ret)
      if (write_table_cb->flush) {
          /* We still need to flush first */
          write_table_cb->flush = false;
 +        qed_acquire(s);
          bdrv_aio_flush(write_table_cb->s->bs, qed_write_table_cb,
                         write_table_cb);
 +        qed_release(s);
          return;
      }
@@ -XXX,XX +XXX,XX @@ static void qed_read_l2_table_cb(void *opaque, int ret)
      CachedL2Table *l2_table = request->l2_table;
      uint64_t l2_offset = read_l2_table_cb->l2_offset;
 +    qed_acquire(s);
      if (ret) {
          /* can't trust loaded L2 table anymore */
          qed_unref_l2_cache_entry(l2_table);
@@ -XXX,XX +XXX,XX @@ static void qed_read_l2_table_cb(void *opaque, int ret)
          request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
          assert(request->l2_table != NULL);
      }
 +    qed_release(s);
      gencb_complete(&read_l2_table_cb->gencb, ret);
  }
 diff --git a/block/qed.c b/block/qed.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/qed.c
 +++ b/block/qed.c
@@ -XXX,XX +XXX,XX @@ static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t l
      }
      if (cb->co) {
 -        qemu_coroutine_enter(cb->co);
 +        aio_co_wake(cb->co);
      }
  }
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn qed_co_pwrite_zeroes_cb(void *opaque, int ret)
      cb->done = true;
      cb->ret = ret;
      if (cb->co) {
 -        qemu_coroutine_enter(cb->co);
 +        aio_co_wake(cb->co);
      }
  }
 diff --git a/block/rbd.c b/block/rbd.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/rbd.c
 +++ b/block/rbd.c
@@ -XXX,XX +XXX,XX @@ shutdown:
  static void qemu_rbd_complete_aio(RADOSCB *rcb)
  {
      RBDAIOCB *acb = rcb->acb;
 -    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
      int64_t r;
      r = rcb->ret;
@@ -XXX,XX +XXX,XX @@ static void qemu_rbd_complete_aio(RADOSCB *rcb)
          qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
      }
      qemu_vfree(acb->bounce);
 -
 -    aio_context_acquire(ctx);
      acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
 -    aio_context_release(ctx);
      qemu_aio_unref(acb);
  }
 diff --git a/block/win32-aio.c b/block/win32-aio.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/win32-aio.c
 +++ b/block/win32-aio.c
@@ -XXX,XX +XXX,XX @@ static void win32_aio_process_completion(QEMUWin32AIOState *s,
          qemu_vfree(waiocb->buf);
      }
 -
 -    aio_context_acquire(s->aio_ctx);
      waiocb->common.cb(waiocb->common.opaque, ret);
 -    aio_context_release(s->aio_ctx);
      qemu_aio_unref(waiocb);
  }
 diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/block/virtio-blk.c
 +++ b/hw/block/virtio-blk.c
@@ -XXX,XX +XXX,XX @@ static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
  static void virtio_blk_rw_complete(void *opaque, int ret)
  {
      VirtIOBlockReq *next = opaque;
 +    VirtIOBlock *s = next->dev;
 +    aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
      while (next) {
          VirtIOBlockReq *req = next;
          next = req->mr_next;
@@ -XXX,XX +XXX,XX @@ static void virtio_blk_rw_complete(void *opaque, int ret)
          block_acct_done(blk_get_stats(req->dev->blk), &req->acct);
          virtio_blk_free_request(req);
      }
 +    aio_context_release(blk_get_aio_context(s->conf.conf.blk));
  }
  static void virtio_blk_flush_complete(void *opaque, int ret)
  {
      VirtIOBlockReq *req = opaque;
 +    VirtIOBlock *s = req->dev;
 +    aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
      if (ret) {
          if (virtio_blk_handle_rw_error(req, -ret, 0)) {
 -            return;
 +            goto out;
          }
      }
+     if (s->to_replace) {
-     virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
+@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
-     block_acct_done(blk_get_stats(req->dev->blk), &req->acct);
+     blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort);
-     virtio_blk_free_request(req);
      bs_opaque->job = NULL;
 -    job_completed(job, data->ret);
 -    g_free(data);
      bdrv_drained_end(src);
      bdrv_unref(mirror_top_bs);
      bdrv_unref(src);
 +
-+out:
++    job->ret = ret;
 +    aio_context_release(blk_get_aio_context(s->conf.conf.blk));
  }
- #ifdef __linux__
+ static void mirror_throttle(MirrorBlockJob *s)
-@@ -XXX,XX +XXX,XX @@ static void virtio_blk_ioctl_complete(void *opaque, int status)
+@@ -XXX,XX +XXX,XX @@ static int mirror_flush(MirrorBlockJob *s)
-     virtio_stl_p(vdev, &scsi->data_len, hdr->dxfer_len);
+ static int coroutine_fn mirror_run(Job *job, Error **errp)
+ {
- out:
+     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
-+    aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
+-    MirrorExitData *data;
-     virtio_blk_req_complete(req, status);
+     BlockDriverState *bs = s->mirror_top_bs->backing->bs;
-     virtio_blk_free_request(req);
+     BlockDriverState *target_bs = blk_bs(s->target);
-+    aio_context_release(blk_get_aio_context(s->conf.conf.blk));
+     bool need_drain = true;
-     g_free(ioctl_req);
+@@ -XXX,XX +XXX,XX @@ immediate_exit:
      g_free(s->in_flight_bitmap);
      bdrv_dirty_iter_free(s->dbi);
 -    data = g_malloc(sizeof(*data));
 -    data->ret = ret;
 -
      if (need_drain) {
          bdrv_drained_begin(bs);
      }
 -    job_defer_to_main_loop(&s->common.job, mirror_exit, data);
      return ret;
  }
-diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
+@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver mirror_job_driver = {
-index XXXXXXX..XXXXXXX 100644
+         .user_resume            = block_job_user_resume,
---- a/hw/scsi/scsi-disk.c
+         .drain                  = block_job_drain,
-+++ b/hw/scsi/scsi-disk.c
+         .run                    = mirror_run,
-@@ -XXX,XX +XXX,XX @@ static void scsi_aio_complete(void *opaque, int ret)
++        .exit                   = mirror_exit,
+         .pause                  = mirror_pause,
-     assert(r->req.aiocb != NULL);
+         .complete               = mirror_complete,
-     r->req.aiocb = NULL;
+     },
-+    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
+@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_active_job_driver = {
-     if (scsi_disk_req_check_error(r, ret, true)) {
+         .user_resume            = block_job_user_resume,
-         goto done;
+         .drain                  = block_job_drain,
-     }
+         .run                    = mirror_run,
-@@ -XXX,XX +XXX,XX @@ static void scsi_aio_complete(void *opaque, int ret)
++        .exit                   = mirror_exit,
-     scsi_req_complete(&r->req, GOOD);
+         .pause                  = mirror_pause,
+         .complete               = mirror_complete,
- done:
+     },
 +    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
      scsi_req_unref(&r->req);
  }
@@ -XXX,XX +XXX,XX @@ static void scsi_dma_complete(void *opaque, int ret)
      assert(r->req.aiocb != NULL);
      r->req.aiocb = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
      if (ret < 0) {
          block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
      } else {
          block_acct_done(blk_get_stats(s->qdev.conf.blk), &r->acct);
      }
      scsi_dma_complete_noio(r, ret);
 +    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
  }
  static void scsi_read_complete(void * opaque, int ret)
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
      assert(r->req.aiocb != NULL);
      r->req.aiocb = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
      if (scsi_disk_req_check_error(r, ret, true)) {
          goto done;
      }
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
  done:
      scsi_req_unref(&r->req);
 +    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
  }
  /* Actually issue a read to the block device.  */
@@ -XXX,XX +XXX,XX @@ static void scsi_do_read_cb(void *opaque, int ret)
      assert (r->req.aiocb != NULL);
      r->req.aiocb = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
      if (ret < 0) {
          block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
      } else {
          block_acct_done(blk_get_stats(s->qdev.conf.blk), &r->acct);
      }
      scsi_do_read(opaque, ret);
 +    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
  }
  /* Read more data from scsi device into buffer.  */
@@ -XXX,XX +XXX,XX @@ static void scsi_write_complete(void * opaque, int ret)
      assert (r->req.aiocb != NULL);
      r->req.aiocb = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
      if (ret < 0) {
          block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
      } else {
          block_acct_done(blk_get_stats(s->qdev.conf.blk), &r->acct);
      }
      scsi_write_complete_noio(r, ret);
 +    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
  }
  static void scsi_write_data(SCSIRequest *req)
@@ -XXX,XX +XXX,XX @@ static void scsi_unmap_complete(void *opaque, int ret)
  {
      UnmapCBData *data = opaque;
      SCSIDiskReq *r = data->r;
 +    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
      assert(r->req.aiocb != NULL);
      r->req.aiocb = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
      scsi_unmap_complete_noio(data, ret);
 +    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
  }
  static void scsi_disk_emulate_unmap(SCSIDiskReq *r, uint8_t *inbuf)
@@ -XXX,XX +XXX,XX @@ static void scsi_write_same_complete(void *opaque, int ret)
      assert(r->req.aiocb != NULL);
      r->req.aiocb = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
      if (scsi_disk_req_check_error(r, ret, true)) {
          goto done;
      }
@@ -XXX,XX +XXX,XX @@ done:
      scsi_req_unref(&r->req);
      qemu_vfree(data->iov.iov_base);
      g_free(data);
 +    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
  }
  static void scsi_disk_emulate_write_same(SCSIDiskReq *r, uint8_t *inbuf)
 diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/scsi/scsi-generic.c
 +++ b/hw/scsi/scsi-generic.c
@@ -XXX,XX +XXX,XX @@ done:
  static void scsi_command_complete(void *opaque, int ret)
  {
      SCSIGenericReq *r = (SCSIGenericReq *)opaque;
 +    SCSIDevice *s = r->req.dev;
      assert(r->req.aiocb != NULL);
      r->req.aiocb = NULL;
 +
 +    aio_context_acquire(blk_get_aio_context(s->conf.blk));
      scsi_command_complete_noio(r, ret);
 +    aio_context_release(blk_get_aio_context(s->conf.blk));
  }
  static int execute_command(BlockBackend *blk,
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
      assert(r->req.aiocb != NULL);
      r->req.aiocb = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->conf.blk));
 +
      if (ret || r->req.io_canceled) {
          scsi_command_complete_noio(r, ret);
 -        return;
 +        goto done;
      }
      len = r->io_header.dxfer_len - r->io_header.resid;
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
      r->len = -1;
      if (len == 0) {
          scsi_command_complete_noio(r, 0);
 -        return;
 +        goto done;
      }
      /* Snoop READ CAPACITY output to set the blocksize.  */
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
      }
      scsi_req_data(&r->req, len);
      scsi_req_unref(&r->req);
 +
 +done:
 +    aio_context_release(blk_get_aio_context(s->conf.blk));
  }
  /* Read more data from scsi device into buffer.  */
@@ -XXX,XX +XXX,XX @@ static void scsi_write_complete(void * opaque, int ret)
      assert(r->req.aiocb != NULL);
      r->req.aiocb = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->conf.blk));
 +
      if (ret || r->req.io_canceled) {
          scsi_command_complete_noio(r, ret);
 -        return;
 +        goto done;
      }
      if (r->req.cmd.buf[0] == MODE_SELECT && r->req.cmd.buf[4] == 12 &&
@@ -XXX,XX +XXX,XX @@ static void scsi_write_complete(void * opaque, int ret)
      }
      scsi_command_complete_noio(r, ret);
 +
 +done:
 +    aio_context_release(blk_get_aio_context(s->conf.blk));
  }
  /* Write data to a scsi device.  Returns nonzero on failure.
 diff --git a/util/thread-pool.c b/util/thread-pool.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/thread-pool.c
 +++ b/util/thread-pool.c
@@ -XXX,XX +XXX,XX @@ restart:
               */
              qemu_bh_schedule(pool->completion_bh);
 +            aio_context_release(pool->ctx);
              elem->common.cb(elem->common.opaque, elem->ret);
 +            aio_context_acquire(pool->ctx);
              qemu_aio_unref(elem);
              goto restart;
          } else {
@@ -XXX,XX +XXX,XX @@ static void thread_pool_co_cb(void *opaque, int ret)
      ThreadPoolCo *co = opaque;
      co->ret = ret;
 -    qemu_coroutine_enter(co->co);
 +    aio_co_wake(co->co);
  }
  int coroutine_fn thread_pool_submit_co(ThreadPool *pool, ThreadPoolFunc *func,
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 13/24] block: explicitly acquire aiocontext in callbacks that need it
+[Qemu-devel] [PULL v2 07/10] jobs: utilize job_exit shim
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: John Snow <jsnow@redhat.com>
-This covers both file descriptor callbacks and polling callbacks,
+Utilize the job_exit shim by not calling job_defer_to_main_loop, and
-since they execute related code.
+where applicable, converting the deferred callback into the job_exit
+callback.
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+This converts backup, stream, create, and the unit tests all at once.
-Reviewed-by: Fam Zheng <famz@redhat.com>
+Most of these jobs do not see any changes to the order in which they
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
+clean up their resources, except the test-blockjob-txn test, which
-Message-id: 20170213135235.12274-14-pbonzini@redhat.com
+now puts down its bs before job_completed is called.
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 This is safe for the same reason the reordering in the mirror job is
 safe, because job_completed no longer runs under two locks, making
 the unref safe even if it causes a flush.
 Signed-off-by: John Snow <jsnow@redhat.com>
 Reviewed-by: Max Reitz <mreitz@redhat.com>
 Message-id: 20180830015734.19765-7-jsnow@redhat.com
 Signed-off-by: Max Reitz <mreitz@redhat.com>
 ---
- block/curl.c          | 16 +++++++++++++---
+ block/backup.c            | 16 ----------------
- block/iscsi.c         |  4 ++++
+ block/create.c            | 14 +++-----------
- block/linux-aio.c     |  4 ++++
+ block/stream.c            | 22 +++++++---------------
- block/nfs.c           |  6 ++++++
+ tests/test-bdrv-drain.c   |  6 ------
- block/sheepdog.c      | 29 +++++++++++++++--------------
+ tests/test-blockjob-txn.c | 11 ++---------
- block/ssh.c           | 29 +++++++++--------------------
+ tests/test-blockjob.c     | 10 ++++------
- block/win32-aio.c     | 10 ++++++----
+files changed, 16 insertions(+), 63 deletions(-)
- hw/block/virtio-blk.c |  5 ++++-
- hw/scsi/virtio-scsi.c |  7 +++++++
+diff --git a/block/backup.c b/block/backup.c
- util/aio-posix.c      |  7 -------
+index XXXXXXX..XXXXXXX 100644
- util/aio-win32.c      |  6 ------
+--- a/block/backup.c
-files changed, 68 insertions(+), 55 deletions(-)
++++ b/block/backup.c
+@@ -XXX,XX +XXX,XX @@ static BlockErrorAction backup_error_action(BackupBlockJob *job,
-diff --git a/block/curl.c b/block/curl.c
+     }
-index XXXXXXX..XXXXXXX 100644
+ }
---- a/block/curl.c
-+++ b/block/curl.c
+-typedef struct {
-@@ -XXX,XX +XXX,XX @@ static void curl_multi_check_completion(BDRVCURLState *s)
+-    int ret;
-     }
+-} BackupCompleteData;
- }
+-
+-static void backup_complete(Job *job, void *opaque)
--static void curl_multi_do(void *arg)
+-{
-+static void curl_multi_do_locked(CURLState *s)
+-    BackupCompleteData *data = opaque;
- {
+-
--    CURLState *s = (CURLState *)arg;
+-    job_completed(job, data->ret);
-     CURLSocket *socket, *next_socket;
+-    g_free(data);
-     int running;
+-}
-     int r;
+-
-@@ -XXX,XX +XXX,XX @@ static void curl_multi_do(void *arg)
+ static bool coroutine_fn yield_and_check(BackupBlockJob *job)
-     }
+ {
- }
+     uint64_t delay_ns;
+@@ -XXX,XX +XXX,XX @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
-+static void curl_multi_do(void *arg)
+ static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
-+{
+ {
-+    CURLState *s = (CURLState *)arg;
+     BackupBlockJob *job = container_of(opaque_job, BackupBlockJob, common.job);
-+
+-    BackupCompleteData *data;
-+    aio_context_acquire(s->s->aio_context);
+     BlockDriverState *bs = blk_bs(job->common.blk);
-+    curl_multi_do_locked(s);
+     int64_t offset, nb_clusters;
-+    aio_context_release(s->s->aio_context);
+     int ret = 0;
-+}
+@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
-+
+     qemu_co_rwlock_unlock(&job->flush_rwlock);
- static void curl_multi_read(void *arg)
+     hbitmap_free(job->copy_bitmap);
- {
-     CURLState *s = (CURLState *)arg;
+-    data = g_malloc(sizeof(*data));
+-    data->ret = ret;
--    curl_multi_do(arg);
+-    job_defer_to_main_loop(&job->common.job, backup_complete, data);
 +    aio_context_acquire(s->s->aio_context);
 +    curl_multi_do_locked(s);
      curl_multi_check_completion(s->s);
 +    aio_context_release(s->s->aio_context);
  }
  static void curl_multi_timeout_do(void *arg)
 diff --git a/block/iscsi.c b/block/iscsi.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/iscsi.c
 +++ b/block/iscsi.c
@@ -XXX,XX +XXX,XX @@ iscsi_process_read(void *arg)
      IscsiLun *iscsilun = arg;
      struct iscsi_context *iscsi = iscsilun->iscsi;
 +    aio_context_acquire(iscsilun->aio_context);
      iscsi_service(iscsi, POLLIN);
      iscsi_set_events(iscsilun);
 +    aio_context_release(iscsilun->aio_context);
  }
  static void
@@ -XXX,XX +XXX,XX @@ iscsi_process_write(void *arg)
      IscsiLun *iscsilun = arg;
      struct iscsi_context *iscsi = iscsilun->iscsi;
 +    aio_context_acquire(iscsilun->aio_context);
      iscsi_service(iscsi, POLLOUT);
      iscsi_set_events(iscsilun);
 +    aio_context_release(iscsilun->aio_context);
  }
  static int64_t sector_lun2qemu(int64_t sector, IscsiLun *iscsilun)
 diff --git a/block/linux-aio.c b/block/linux-aio.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/linux-aio.c
 +++ b/block/linux-aio.c
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_completion_cb(EventNotifier *e)
      LinuxAioState *s = container_of(e, LinuxAioState, e);
      if (event_notifier_test_and_clear(&s->e)) {
 +        aio_context_acquire(s->aio_context);
          qemu_laio_process_completions_and_submit(s);
 +        aio_context_release(s->aio_context);
      }
  }
@@ -XXX,XX +XXX,XX @@ static bool qemu_laio_poll_cb(void *opaque)
          return false;
      }
 +    aio_context_acquire(s->aio_context);
      qemu_laio_process_completions_and_submit(s);
 +    aio_context_release(s->aio_context);
      return true;
  }
 diff --git a/block/nfs.c b/block/nfs.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/nfs.c
 +++ b/block/nfs.c
@@ -XXX,XX +XXX,XX @@ static void nfs_set_events(NFSClient *client)
  static void nfs_process_read(void *arg)
  {
      NFSClient *client = arg;
 +
 +    aio_context_acquire(client->aio_context);
      nfs_service(client->context, POLLIN);
      nfs_set_events(client);
 +    aio_context_release(client->aio_context);
  }
  static void nfs_process_write(void *arg)
  {
      NFSClient *client = arg;
 +
 +    aio_context_acquire(client->aio_context);
      nfs_service(client->context, POLLOUT);
      nfs_set_events(client);
 +    aio_context_release(client->aio_context);
  }
  static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
 diff --git a/block/sheepdog.c b/block/sheepdog.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/sheepdog.c
 +++ b/block/sheepdog.c
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int send_co_req(int sockfd, SheepdogReq *hdr, void *data,
      return ret;
  }
--static void restart_co_req(void *opaque)
+diff --git a/block/create.c b/block/create.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/create.c
 +++ b/block/create.c
@@ -XXX,XX +XXX,XX @@ typedef struct BlockdevCreateJob {
      Job common;
      BlockDriver *drv;
      BlockdevCreateOptions *opts;
 -    int ret;
  } BlockdevCreateJob;
 -static void blockdev_create_complete(Job *job, void *opaque)
 -{
--    Coroutine *co = opaque;
+-    BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
 -
--    qemu_coroutine_enter(co);
+-    job_completed(job, s->ret);
 -}
 -
- typedef struct SheepdogReqCo {
+ static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
-     int sockfd;
+ {
-     BlockDriverState *bs;
+     BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
-@@ -XXX,XX +XXX,XX @@ typedef struct SheepdogReqCo {
++    int ret;
-     unsigned int *rlen;
-     int ret;
+     job_progress_set_remaining(&s->common, 1);
-     bool finished;
+-    s->ret = s->drv->bdrv_co_create(s->opts, errp);
-+    Coroutine *co;
++    ret = s->drv->bdrv_co_create(s->opts, errp);
- } SheepdogReqCo;
+     job_progress_update(&s->common, 1);
-+static void restart_co_req(void *opaque)
+     qapi_free_BlockdevCreateOptions(s->opts);
-+{
+-    job_defer_to_main_loop(&s->common, blockdev_create_complete, NULL);
-+    SheepdogReqCo *srco = opaque;
-+
+-    return s->ret;
-+    aio_co_wake(srco->co);
++    return ret;
-+}
+ }
-+
- static coroutine_fn void do_co_req(void *opaque)
+ static const JobDriver blockdev_create_job_driver = {
- {
+diff --git a/block/stream.c b/block/stream.c
-     int ret;
+index XXXXXXX..XXXXXXX 100644
--    Coroutine *co;
+--- a/block/stream.c
-     SheepdogReqCo *srco = opaque;
++++ b/block/stream.c
-     int sockfd = srco->sockfd;
+@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_populate(BlockBackend *blk,
-     SheepdogReq *hdr = srco->hdr;
+     return blk_co_preadv(blk, offset, qiov.size, &qiov, BDRV_REQ_COPY_ON_READ);
-@@ -XXX,XX +XXX,XX @@ static coroutine_fn void do_co_req(void *opaque)
+ }
-     unsigned int *wlen = srco->wlen;
-     unsigned int *rlen = srco->rlen;
+-typedef struct {
+-    int ret;
--    co = qemu_coroutine_self();
+-} StreamCompleteData;
-+    srco->co = qemu_coroutine_self();
+-
-     aio_set_fd_handler(srco->aio_context, sockfd, false,
+-static void stream_complete(Job *job, void *opaque)
--                       NULL, restart_co_req, NULL, co);
++static void stream_exit(Job *job)
-+                       NULL, restart_co_req, NULL, srco);
+ {
+     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
-     ret = send_co_req(sockfd, hdr, data, wlen);
+     BlockJob *bjob = &s->common;
-     if (ret < 0) {
+-    StreamCompleteData *data = opaque;
-@@ -XXX,XX +XXX,XX @@ static coroutine_fn void do_co_req(void *opaque)
+     BlockDriverState *bs = blk_bs(bjob->blk);
-     }
+     BlockDriverState *base = s->base;
+     Error *local_err = NULL;
-     aio_set_fd_handler(srco->aio_context, sockfd, false,
++    int ret = job->ret;
--                       restart_co_req, NULL, NULL, co);
-+                       restart_co_req, NULL, NULL, srco);
+-    if (!job_is_cancelled(job) && bs->backing && data->ret == 0) {
++    if (!job_is_cancelled(job) && bs->backing && ret == 0) {
-     ret = qemu_co_recv(sockfd, hdr, sizeof(*hdr));
+         const char *base_id = NULL, *base_fmt = NULL;
-     if (ret != sizeof(*hdr)) {
+         if (base) {
              base_id = s->backing_file_str;
@@ -XXX,XX +XXX,XX @@ static void stream_complete(Job *job, void *opaque)
                  base_fmt = base->drv->format_name;
              }
          }
 -        data->ret = bdrv_change_backing_file(bs, base_id, base_fmt);
 +        ret = bdrv_change_backing_file(bs, base_id, base_fmt);
          bdrv_set_backing_hd(bs, base, &local_err);
          if (local_err) {
              error_report_err(local_err);
 -            data->ret = -EPERM;
 +            ret = -EPERM;
              goto out;
          }
      }
 @@ -XXX,XX +XXX,XX @@ out:
-     aio_set_fd_handler(srco->aio_context, sockfd, false,
+     }
-                        NULL, NULL, NULL, NULL);
+     g_free(s->backing_file_str);
-+    srco->co = NULL;
+-    job_completed(job, data->ret);
-     srco->ret = ret;
+-    g_free(data);
-     srco->finished = true;
++    job->ret = ret;
-     if (srco->bs) {
+ }
-@@ -XXX,XX +XXX,XX @@ static void coroutine_fn aio_read_response(void *opaque)
-          * We've finished all requests which belong to the AIOCB, so
+ static int coroutine_fn stream_run(Job *job, Error **errp)
-          * we can switch back to sd_co_readv/writev now.
+ {
-          */
+     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
--        qemu_coroutine_enter(acb->coroutine);
+-    StreamCompleteData *data;
-+        aio_co_wake(acb->coroutine);
+     BlockBackend *blk = s->common.blk;
-     }
+     BlockDriverState *bs = blk_bs(blk);
+     BlockDriverState *base = s->base;
-     return;
+@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_run(Job *job, Error **errp)
-@@ -XXX,XX +XXX,XX @@ static void co_read_response(void *opaque)
-         s->co_recv = qemu_coroutine_create(aio_read_response, opaque);
+ out:
-     }
+     /* Modify backing chain and close BDSes in main loop */
+-    data = g_malloc(sizeof(*data));
--    qemu_coroutine_enter(s->co_recv);
+-    data->ret = ret;
-+    aio_co_wake(s->co_recv);
+-    job_defer_to_main_loop(&s->common.job, stream_complete, data);
- }
+     return ret;
+ }
- static void co_write_request(void *opaque)
- {
+@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver stream_job_driver = {
-     BDRVSheepdogState *s = opaque;
+         .job_type      = JOB_TYPE_STREAM,
+         .free          = block_job_free,
--    qemu_coroutine_enter(s->co_send);
+         .run           = stream_run,
-+    aio_co_wake(s->co_send);
++        .exit          = stream_exit,
- }
+         .user_resume   = block_job_user_resume,
+         .drain         = block_job_drain,
- /*
+     },
-diff --git a/block/ssh.c b/block/ssh.c
+diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
 index XXXXXXX..XXXXXXX 100644
---- a/block/ssh.c
+--- a/tests/test-bdrv-drain.c
-+++ b/block/ssh.c
++++ b/tests/test-bdrv-drain.c
-@@ -XXX,XX +XXX,XX @@ static void restart_coroutine(void *opaque)
+@@ -XXX,XX +XXX,XX @@ typedef struct TestBlockJob {
+     bool should_complete;
-     DPRINTF("co=%p", co);
+ } TestBlockJob;
--    qemu_coroutine_enter(co);
+-static void test_job_completed(Job *job, void *opaque)
-+    aio_co_wake(co);
+-{
- }
+-    job_completed(job, 0);
 -static coroutine_fn void set_fd_handler(BDRVSSHState *s, BlockDriverState *bs)
 +/* A non-blocking call returned EAGAIN, so yield, ensuring the
 + * handlers are set up so that we'll be rescheduled when there is an
 + * interesting event on the socket.
 + */
 +static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
  {
      int r;
      IOHandler *rd_handler = NULL, *wr_handler = NULL;
@@ -XXX,XX +XXX,XX @@ static coroutine_fn void set_fd_handler(BDRVSSHState *s, BlockDriverState *bs)
      aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
                         false, rd_handler, wr_handler, NULL, co);
 -}
 -
--static coroutine_fn void clear_fd_handler(BDRVSSHState *s,
+ static int coroutine_fn test_job_run(Job *job, Error **errp)
--                                          BlockDriverState *bs)
+ {
--{
+     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
--    DPRINTF("s->sock=%d", s->sock);
+@@ -XXX,XX +XXX,XX @@ static int coroutine_fn test_job_run(Job *job, Error **errp)
--    aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
+         job_pause_point(&s->common.job);
--                       false, NULL, NULL, NULL, NULL);
+     }
--}
--
+-    job_defer_to_main_loop(&s->common.job, test_job_completed, NULL);
--/* A non-blocking call returned EAGAIN, so yield, ensuring the
+     return 0;
-- * handlers are set up so that we'll be rescheduled when there is an
+ }
-- * interesting event on the socket.
-- */
+diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
--static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
+index XXXXXXX..XXXXXXX 100644
--{
+--- a/tests/test-blockjob-txn.c
--    set_fd_handler(s, bs);
++++ b/tests/test-blockjob-txn.c
-     qemu_coroutine_yield();
+@@ -XXX,XX +XXX,XX @@ typedef struct {
--    clear_fd_handler(s, bs);
+     int *result;
-+    DPRINTF("s->sock=%d - back", s->sock);
+ } TestBlockJob;
-+    aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock, false,
-+                       NULL, NULL, NULL, NULL);
+-static void test_block_job_complete(Job *job, void *opaque)
- }
++static void test_block_job_exit(Job *job)
+ {
- /* SFTP has a function `libssh2_sftp_seek64' which seeks to a position
+     BlockJob *bjob = container_of(job, BlockJob, job);
-diff --git a/block/win32-aio.c b/block/win32-aio.c
+     BlockDriverState *bs = blk_bs(bjob->blk);
-index XXXXXXX..XXXXXXX 100644
+-    int rc = (intptr_t)opaque;
---- a/block/win32-aio.c
-+++ b/block/win32-aio.c
+-    if (job_is_cancelled(job)) {
-@@ -XXX,XX +XXX,XX @@ struct QEMUWin32AIOState {
+-        rc = -ECANCELED;
-     HANDLE hIOCP;
+-    }
-     EventNotifier e;
+-
-     int count;
+-    job_completed(job, rc);
--    bool is_aio_context_attached;
+     bdrv_unref(bs);
-+    AioContext *aio_ctx;
+ }
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn test_block_job_run(Job *job, Error **errp)
          }
      }
 -    job_defer_to_main_loop(job, test_block_job_complete,
 -                           (void *)(intptr_t)s->rc);
      return s->rc;
  }
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_block_job_driver = {
          .user_resume   = block_job_user_resume,
          .drain         = block_job_drain,
          .run           = test_block_job_run,
 +        .exit          = test_block_job_exit,
      },
  };
- typedef struct QEMUWin32AIOCB {
+diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
-@@ -XXX,XX +XXX,XX @@ static void win32_aio_process_completion(QEMUWin32AIOState *s,
+index XXXXXXX..XXXXXXX 100644
-     }
+--- a/tests/test-blockjob.c
++++ b/tests/test-blockjob.c
+@@ -XXX,XX +XXX,XX @@ typedef struct CancelJob {
-+    aio_context_acquire(s->aio_ctx);
+     bool completed;
-     waiocb->common.cb(waiocb->common.opaque, ret);
+ } CancelJob;
-+    aio_context_release(s->aio_ctx);
-     qemu_aio_unref(waiocb);
+-static void cancel_job_completed(Job *job, void *opaque)
- }
++static void cancel_job_exit(Job *job)
+ {
-@@ -XXX,XX +XXX,XX @@ void win32_aio_detach_aio_context(QEMUWin32AIOState *aio,
+-    CancelJob *s = opaque;
-                                   AioContext *old_context)
++    CancelJob *s = container_of(job, CancelJob, common.job);
- {
+     s->completed = true;
-     aio_set_event_notifier(old_context, &aio->e, false, NULL, NULL);
+-    job_completed(job, 0);
--    aio->is_aio_context_attached = false;
+ }
-+    aio->aio_ctx = NULL;
- }
+ static void cancel_job_complete(Job *job, Error **errp)
+@@ -XXX,XX +XXX,XX @@ static int coroutine_fn cancel_job_run(Job *job, Error **errp)
- void win32_aio_attach_aio_context(QEMUWin32AIOState *aio,
-                                   AioContext *new_context)
+     while (!s->should_complete) {
- {
+         if (job_is_cancelled(&s->common.job)) {
--    aio->is_aio_context_attached = true;
+-            goto defer;
-+    aio->aio_ctx = new_context;
++            return 0;
-     aio_set_event_notifier(new_context, &aio->e, false,
+         }
-                            win32_aio_completion_cb, NULL);
- }
+         if (!job_is_ready(&s->common.job) && s->should_converge) {
-@@ -XXX,XX +XXX,XX @@ out_free_state:
+@@ -XXX,XX +XXX,XX @@ static int coroutine_fn cancel_job_run(Job *job, Error **errp)
+         job_sleep_ns(&s->common.job, 100000);
- void win32_aio_cleanup(QEMUWin32AIOState *aio)
+     }
- {
--    assert(!aio->is_aio_context_attached);
+- defer:
-+    assert(!aio->aio_ctx);
+-    job_defer_to_main_loop(&s->common.job, cancel_job_completed, s);
-     CloseHandle(aio->hIOCP);
+     return 0;
-     event_notifier_cleanup(&aio->e);
+ }
-     g_free(aio);
-diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
+@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_cancel_driver = {
-index XXXXXXX..XXXXXXX 100644
+         .user_resume   = block_job_user_resume,
---- a/hw/block/virtio-blk.c
+         .drain         = block_job_drain,
-+++ b/hw/block/virtio-blk.c
+         .run           = cancel_job_run,
-@@ -XXX,XX +XXX,XX @@ static void virtio_blk_ioctl_complete(void *opaque, int status)
++        .exit          = cancel_job_exit,
- {
+         .complete      = cancel_job_complete,
-     VirtIOBlockIoctlReq *ioctl_req = opaque;
+     },
-     VirtIOBlockReq *req = ioctl_req->req;
+ };
 -    VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
 +    VirtIOBlock *s = req->dev;
 +    VirtIODevice *vdev = VIRTIO_DEVICE(s);
      struct virtio_scsi_inhdr *scsi;
      struct sg_io_hdr *hdr;
@@ -XXX,XX +XXX,XX @@ bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
      MultiReqBuffer mrb = {};
      bool progress = false;
 +    aio_context_acquire(blk_get_aio_context(s->blk));
      blk_io_plug(s->blk);
      do {
@@ -XXX,XX +XXX,XX @@ bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
      }
      blk_io_unplug(s->blk);
 +    aio_context_release(blk_get_aio_context(s->blk));
      return progress;
  }
 diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/scsi/virtio-scsi.c
 +++ b/hw/scsi/virtio-scsi.c
@@ -XXX,XX +XXX,XX @@ bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
      VirtIOSCSIReq *req;
      bool progress = false;
 +    virtio_scsi_acquire(s);
      while ((req = virtio_scsi_pop_req(s, vq))) {
          progress = true;
          virtio_scsi_handle_ctrl_req(s, req);
      }
 +    virtio_scsi_release(s);
      return progress;
  }
@@ -XXX,XX +XXX,XX @@ bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
      QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
 +    virtio_scsi_acquire(s);
      do {
          virtio_queue_set_notification(vq, 0);
@@ -XXX,XX +XXX,XX @@ bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
      QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
          virtio_scsi_handle_cmd_req_submit(s, req);
      }
 +    virtio_scsi_release(s);
      return progress;
  }
@@ -XXX,XX +XXX,XX @@ out:
  bool virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
  {
 +    virtio_scsi_acquire(s);
      if (s->events_dropped) {
          virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
 +        virtio_scsi_release(s);
          return true;
      }
 +    virtio_scsi_release(s);
      return false;
  }
 diff --git a/util/aio-posix.c b/util/aio-posix.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/aio-posix.c
 +++ b/util/aio-posix.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
              (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) &&
              aio_node_check(ctx, node->is_external) &&
              node->io_read) {
 -            aio_context_acquire(ctx);
              node->io_read(node->opaque);
 -            aio_context_release(ctx);
              /* aio_notify() does not count as progress */
              if (node->opaque != &ctx->notifier) {
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
              (revents & (G_IO_OUT | G_IO_ERR)) &&
              aio_node_check(ctx, node->is_external) &&
              node->io_write) {
 -            aio_context_acquire(ctx);
              node->io_write(node->opaque);
 -            aio_context_release(ctx);
              progress = true;
          }
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
          start = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
      }
 -    aio_context_acquire(ctx);
      progress = try_poll_mode(ctx, blocking);
 -    aio_context_release(ctx);
 -
      if (!progress) {
          assert(npfd == 0);
 diff --git a/util/aio-win32.c b/util/aio-win32.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/aio-win32.c
 +++ b/util/aio-win32.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
              (revents || event_notifier_get_handle(node->e) == event) &&
              node->io_notify) {
              node->pfd.revents = 0;
 -            aio_context_acquire(ctx);
              node->io_notify(node->e);
 -            aio_context_release(ctx);
              /* aio_notify() does not count as progress */
              if (node->e != &ctx->notifier) {
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
              (node->io_read || node->io_write)) {
              node->pfd.revents = 0;
              if ((revents & G_IO_IN) && node->io_read) {
 -                aio_context_acquire(ctx);
                  node->io_read(node->opaque);
 -                aio_context_release(ctx);
                  progress = true;
              }
              if ((revents & G_IO_OUT) && node->io_write) {
 -                aio_context_acquire(ctx);
                  node->io_write(node->opaque);
 -                aio_context_release(ctx);
                  progress = true;
              }
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 17/24] async: remove unnecessary inc/dec pairs
+[Qemu-devel] [PULL v2 08/10] block/backup: make function variables consistently named
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: John Snow <jsnow@redhat.com>
-Pull the increment/decrement pair out of aio_bh_poll and into the
+Rename opaque_job to job to be consistent with other job implementations.
-callers.
+Rename 'job', the BackupBlockJob object, to 's' to also be consistent.
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Suggested-by: Eric Blake <eblake@redhat.com>
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+Signed-off-by: John Snow <jsnow@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
+Reviewed-by: Max Reitz <mreitz@redhat.com>
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
+Message-id: 20180830015734.19765-8-jsnow@redhat.com
-Message-id: 20170213135235.12274-18-pbonzini@redhat.com
+Signed-off-by: Max Reitz <mreitz@redhat.com>
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
- util/aio-posix.c |  8 +++-----
+ block/backup.c | 62 +++++++++++++++++++++++++-------------------------
- util/aio-win32.c |  8 ++++----
+file changed, 31 insertions(+), 31 deletions(-)
  util/async.c     | 12 ++++++------
 files changed, 13 insertions(+), 15 deletions(-)
-diff --git a/util/aio-posix.c b/util/aio-posix.c
+diff --git a/block/backup.c b/block/backup.c
 index XXXXXXX..XXXXXXX 100644
---- a/util/aio-posix.c
+--- a/block/backup.c
-+++ b/util/aio-posix.c
++++ b/block/backup.c
-@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
+@@ -XXX,XX +XXX,XX @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
+     bdrv_dirty_iter_free(dbi);
- void aio_dispatch(AioContext *ctx)
+ }
 -static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
 +static int coroutine_fn backup_run(Job *job, Error **errp)
  {
-+    qemu_lockcnt_inc(&ctx->list_lock);
+-    BackupBlockJob *job = container_of(opaque_job, BackupBlockJob, common.job);
-     aio_bh_poll(ctx);
+-    BlockDriverState *bs = blk_bs(job->common.blk);
--
++    BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
--    qemu_lockcnt_inc(&ctx->list_lock);
++    BlockDriverState *bs = blk_bs(s->common.blk);
-     aio_dispatch_handlers(ctx);
+     int64_t offset, nb_clusters;
-     qemu_lockcnt_dec(&ctx->list_lock);
+     int ret = 0;
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
+-    QLIST_INIT(&job->inflight_reqs);
 -    qemu_co_rwlock_init(&job->flush_rwlock);
 +    QLIST_INIT(&s->inflight_reqs);
 +    qemu_co_rwlock_init(&s->flush_rwlock);
 -    nb_clusters = DIV_ROUND_UP(job->len, job->cluster_size);
 -    job_progress_set_remaining(&job->common.job, job->len);
 +    nb_clusters = DIV_ROUND_UP(s->len, s->cluster_size);
 +    job_progress_set_remaining(job, s->len);
 -    job->copy_bitmap = hbitmap_alloc(nb_clusters, 0);
 -    if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
 -        backup_incremental_init_copy_bitmap(job);
 +    s->copy_bitmap = hbitmap_alloc(nb_clusters, 0);
 +    if (s->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
 +        backup_incremental_init_copy_bitmap(s);
      } else {
 -        hbitmap_set(job->copy_bitmap, 0, nb_clusters);
 +        hbitmap_set(s->copy_bitmap, 0, nb_clusters);
      }
-     npfd = 0;
--    qemu_lockcnt_dec(&ctx->list_lock);
+-    job->before_write.notify = backup_before_write_notify;
+-    bdrv_add_before_write_notifier(bs, &job->before_write);
-     progress |= aio_bh_poll(ctx);
++    s->before_write.notify = backup_before_write_notify;
++    bdrv_add_before_write_notifier(bs, &s->before_write);
-     if (ret > 0) {
--        qemu_lockcnt_inc(&ctx->list_lock);
+-    if (job->sync_mode == MIRROR_SYNC_MODE_NONE) {
-         progress |= aio_dispatch_handlers(ctx);
++    if (s->sync_mode == MIRROR_SYNC_MODE_NONE) {
--        qemu_lockcnt_dec(&ctx->list_lock);
+         /* All bits are set in copy_bitmap to allow any cluster to be copied.
-     }
+          * This does not actually require them to be copied. */
+-        while (!job_is_cancelled(&job->common.job)) {
-+    qemu_lockcnt_dec(&ctx->list_lock);
++        while (!job_is_cancelled(job)) {
-+
+             /* Yield until the job is cancelled.  We just let our before_write
-     progress |= timerlistgroup_run_timers(&ctx->tlg);
+              * notify callback service CoW requests. */
+-            job_yield(&job->common.job);
-     return progress;
++            job_yield(job);
-diff --git a/util/aio-win32.c b/util/aio-win32.c
+         }
-index XXXXXXX..XXXXXXX 100644
+-    } else if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
---- a/util/aio-win32.c
+-        ret = backup_run_incremental(job);
-+++ b/util/aio-win32.c
++    } else if (s->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
-@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
++        ret = backup_run_incremental(s);
-     bool progress = false;
+     } else {
-     AioHandler *tmp;
+         /* Both FULL and TOP SYNC_MODE's require copying.. */
+-        for (offset = 0; offset < job->len;
--    qemu_lockcnt_inc(&ctx->list_lock);
+-             offset += job->cluster_size) {
--
++        for (offset = 0; offset < s->len;
-     /*
++             offset += s->cluster_size) {
-      * We have to walk very carefully in case aio_set_fd_handler is
+             bool error_is_read;
-      * called while we're walking.
+             int alloced = 0;
-@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
 -            if (yield_and_check(job)) {
 +            if (yield_and_check(s)) {
                  break;
              }
 -            if (job->sync_mode == MIRROR_SYNC_MODE_TOP) {
 +            if (s->sync_mode == MIRROR_SYNC_MODE_TOP) {
                  int i;
                  int64_t n;
                  /* Check to see if these blocks are already in the
                   * backing file. */
 -                for (i = 0; i < job->cluster_size;) {
 +                for (i = 0; i < s->cluster_size;) {
                      /* bdrv_is_allocated() only returns true/false based
                       * on the first set of sectors it comes across that
                       * are are all in the same state.
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
                       * needed but at some point that is always the case. */
                      alloced =
                          bdrv_is_allocated(bs, offset + i,
 -                                          job->cluster_size - i, &n);
 +                                          s->cluster_size - i, &n);
                      i += n;
                      if (alloced || n == 0) {
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
              if (alloced < 0) {
                  ret = alloced;
              } else {
 -                ret = backup_do_cow(job, offset, job->cluster_size,
 +                ret = backup_do_cow(s, offset, s->cluster_size,
                                      &error_is_read, false);
              }
              if (ret < 0) {
                  /* Depending on error action, fail now or retry cluster */
                  BlockErrorAction action =
 -                    backup_error_action(job, error_is_read, -ret);
 +                    backup_error_action(s, error_is_read, -ret);
                  if (action == BLOCK_ERROR_ACTION_REPORT) {
                      break;
                  } else {
 -                    offset -= job->cluster_size;
 +                    offset -= s->cluster_size;
                      continue;
                  }
              }
          }
      }
--    qemu_lockcnt_dec(&ctx->list_lock);
+-    notifier_with_return_remove(&job->before_write);
-     return progress;
++    notifier_with_return_remove(&s->before_write);
- }
+     /* wait until pending backup_do_cow() calls have completed */
- void aio_dispatch(AioContext *ctx)
+-    qemu_co_rwlock_wrlock(&job->flush_rwlock);
- {
+-    qemu_co_rwlock_unlock(&job->flush_rwlock);
-+    qemu_lockcnt_inc(&ctx->list_lock);
+-    hbitmap_free(job->copy_bitmap);
-     aio_bh_poll(ctx);
++    qemu_co_rwlock_wrlock(&s->flush_rwlock);
-     aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);
++    qemu_co_rwlock_unlock(&s->flush_rwlock);
-+    qemu_lockcnt_dec(&ctx->list_lock);
++    hbitmap_free(s->copy_bitmap);
-     timerlistgroup_run_timers(&ctx->tlg);
  }
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
          }
      }
 -    qemu_lockcnt_dec(&ctx->list_lock);
      first = true;
      /* ctx->notifier is always registered.  */
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
          progress |= aio_dispatch_handlers(ctx, event);
      } while (count > 0);
 +    qemu_lockcnt_dec(&ctx->list_lock);
 +
      progress |= timerlistgroup_run_timers(&ctx->tlg);
      return progress;
  }
 diff --git a/util/async.c b/util/async.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/async.c
 +++ b/util/async.c
@@ -XXX,XX +XXX,XX @@ void aio_bh_call(QEMUBH *bh)
      bh->cb(bh->opaque);
  }
 -/* Multiple occurrences of aio_bh_poll cannot be called concurrently */
 +/* Multiple occurrences of aio_bh_poll cannot be called concurrently.
 + * The count in ctx->list_lock is incremented before the call, and is
 + * not affected by the call.
 + */
  int aio_bh_poll(AioContext *ctx)
  {
      QEMUBH *bh, **bhp, *next;
      int ret;
      bool deleted = false;
 -    qemu_lockcnt_inc(&ctx->list_lock);
 -
      ret = 0;
      for (bh = atomic_rcu_read(&ctx->first_bh); bh; bh = next) {
          next = atomic_rcu_read(&bh->next);
@@ -XXX,XX +XXX,XX @@ int aio_bh_poll(AioContext *ctx)
      /* remove deleted bhs */
      if (!deleted) {
 -        qemu_lockcnt_dec(&ctx->list_lock);
          return ret;
      }
 -    if (qemu_lockcnt_dec_and_lock(&ctx->list_lock)) {
 +    if (qemu_lockcnt_dec_if_lock(&ctx->list_lock)) {
          bhp = &ctx->first_bh;
          while (*bhp) {
              bh = *bhp;
@@ -XXX,XX +XXX,XX @@ int aio_bh_poll(AioContext *ctx)
                  bhp = &bh->next;
              }
          }
 -        qemu_lockcnt_unlock(&ctx->list_lock);
 +        qemu_lockcnt_inc_and_unlock(&ctx->list_lock);
      }
      return ret;
  }
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 14/24] block: explicitly acquire aiocontext in bottom halves that need it
+[Qemu-devel] [PULL v2 09/10] jobs: remove ret argument to job_completed; privatize it
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: John Snow <jsnow@redhat.com>
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+Jobs are now expected to return their retcode on the stack, from the
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
+.run callback, so we can remove that argument.
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
+job_cancel does not need to set -ECANCELED because job_completed will
-Message-id: 20170213135235.12274-15-pbonzini@redhat.com
+update the return code itself if the job was canceled.
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 While we're here, make job_completed static to job.c and remove it from
 job.h; move the documentation of return code to the .run() callback and
 to the job->ret property, accordingly.
 Signed-off-by: John Snow <jsnow@redhat.com>
 Message-id: 20180830015734.19765-9-jsnow@redhat.com
 Reviewed-by: Max Reitz <mreitz@redhat.com>
 Signed-off-by: Max Reitz <mreitz@redhat.com>
 ---
- block/archipelago.c   |  3 +++
+ include/qemu/job.h | 28 +++++++++++++++-------------
- block/blkreplay.c     |  2 +-
+ job.c              | 11 ++++++-----
- block/block-backend.c |  6 ++++++
+ trace-events       |  2 +-
- block/curl.c          | 26 ++++++++++++++++++--------
+files changed, 22 insertions(+), 19 deletions(-)
  block/gluster.c       |  9 +--------
  block/io.c            |  6 +++++-
  block/iscsi.c         |  6 +++++-
  block/linux-aio.c     | 15 +++++++++------
  block/nfs.c           |  3 ++-
  block/null.c          |  4 ++++
  block/qed.c           |  3 +++
  block/rbd.c           |  4 ++++
  dma-helpers.c         |  2 ++
  hw/block/virtio-blk.c |  2 ++
  hw/scsi/scsi-bus.c    |  2 ++
  util/async.c          |  4 ++--
  util/thread-pool.c    |  2 ++
 files changed, 71 insertions(+), 28 deletions(-)
-diff --git a/block/archipelago.c b/block/archipelago.c
+diff --git a/include/qemu/job.h b/include/qemu/job.h
 index XXXXXXX..XXXXXXX 100644
---- a/block/archipelago.c
+--- a/include/qemu/job.h
-+++ b/block/archipelago.c
++++ b/include/qemu/job.h
-@@ -XXX,XX +XXX,XX @@ static void qemu_archipelago_complete_aio(void *opaque)
+@@ -XXX,XX +XXX,XX @@ typedef struct Job {
- {
+     /** Estimated progress_current value at the completion of the job */
-     AIORequestData *reqdata = (AIORequestData *) opaque;
+     int64_t progress_total;
-     ArchipelagoAIOCB *aio_cb = (ArchipelagoAIOCB *) reqdata->aio_cb;
-+    AioContext *ctx = bdrv_get_aio_context(aio_cb->common.bs);
+-    /** ret code passed to job_completed. */
++    /**
-+    aio_context_acquire(ctx);
++     * Return code from @run and/or @prepare callback(s).
-     aio_cb->common.cb(aio_cb->common.opaque, aio_cb->ret);
++     * Not final until the job has reached the CONCLUDED status.
-+    aio_context_release(ctx);
++     * 0 on success, -errno on failure.
-     aio_cb->status = 0;
++     */
+     int ret;
-     qemu_aio_unref(aio_cb);
-diff --git a/block/blkreplay.c b/block/blkreplay.c
+     /**
-index XXXXXXX..XXXXXXX 100755
+@@ -XXX,XX +XXX,XX @@ struct JobDriver {
---- a/block/blkreplay.c
+     /** Enum describing the operation */
-+++ b/block/blkreplay.c
+     JobType job_type;
-@@ -XXX,XX +XXX,XX @@ static int64_t blkreplay_getlength(BlockDriverState *bs)
- static void blkreplay_bh_cb(void *opaque)
+-    /** Mandatory: Entrypoint for the Coroutine. */
- {
++    /**
-     Request *req = opaque;
++     * Mandatory: Entrypoint for the Coroutine.
--    qemu_coroutine_enter(req->co);
++     *
-+    aio_co_wake(req->co);
++     * This callback will be invoked when moving from CREATED to RUNNING.
-     qemu_bh_delete(req->bh);
++     *
-     g_free(req);
++     * If this callback returns nonzero, the job transaction it is part of is
- }
++     * aborted. If it returns zero, the job moves into the WAITING state. If it
-diff --git a/block/block-backend.c b/block/block-backend.c
++     * is the last job to complete in its transaction, all jobs in the
 +     * transaction move from WAITING to PENDING.
 +     */
      int coroutine_fn (*run)(Job *job, Error **errp);
      /**
@@ -XXX,XX +XXX,XX @@ void job_early_fail(Job *job);
  /** Moves the @job from RUNNING to READY */
  void job_transition_to_ready(Job *job);
 -/**
 - * @job: The job being completed.
 - * @ret: The status code.
 - *
 - * Marks @job as completed. If @ret is non-zero, the job transaction it is part
 - * of is aborted. If @ret is zero, the job moves into the WAITING state. If it
 - * is the last job to complete in its transaction, all jobs in the transaction
 - * move from WAITING to PENDING.
 - */
 -void job_completed(Job *job, int ret);
 -
  /** Asynchronously complete the specified @job. */
  void job_complete(Job *job, Error **errp);
 diff --git a/job.c b/job.c
 index XXXXXXX..XXXXXXX 100644
---- a/block/block-backend.c
+--- a/job.c
-+++ b/block/block-backend.c
++++ b/job.c
-@@ -XXX,XX +XXX,XX @@ int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags)
+@@ -XXX,XX +XXX,XX @@ void job_drain(Job *job)
  static void error_callback_bh(void *opaque)
  {
      struct BlockBackendAIOCB *acb = opaque;
 +    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
      bdrv_dec_in_flight(acb->common.bs);
 +    aio_context_acquire(ctx);
      acb->common.cb(acb->common.opaque, acb->ret);
 +    aio_context_release(ctx);
      qemu_aio_unref(acb);
  }
@@ -XXX,XX +XXX,XX @@ static void blk_aio_complete(BlkAioEmAIOCB *acb)
  static void blk_aio_complete_bh(void *opaque)
  {
      BlkAioEmAIOCB *acb = opaque;
 +    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
      assert(acb->has_returned);
 +    aio_context_acquire(ctx);
      blk_aio_complete(acb);
 +    aio_context_release(ctx);
  }
  static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes,
 diff --git a/block/curl.c b/block/curl.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/curl.c
 +++ b/block/curl.c
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
  {
      CURLState *state;
      int running;
 +    int ret = -EINPROGRESS;
      CURLAIOCB *acb = p;
 -    BDRVCURLState *s = acb->common.bs->opaque;
 +    BlockDriverState *bs = acb->common.bs;
 +    BDRVCURLState *s = bs->opaque;
 +    AioContext *ctx = bdrv_get_aio_context(bs);
      size_t start = acb->sector_num * BDRV_SECTOR_SIZE;
      size_t end;
 +    aio_context_acquire(ctx);
 +
      // In case we have the requested data already (e.g. read-ahead),
      // we can just call the callback and be done.
      switch (curl_find_buf(s, start, acb->nb_sectors * BDRV_SECTOR_SIZE, acb)) {
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
              qemu_aio_unref(acb);
              // fall through
          case FIND_RET_WAIT:
 -            return;
 +            goto out;
          default:
              break;
      }
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
      // No cache found, so let's start a new request
      state = curl_init_state(acb->common.bs, s);
      if (!state) {
 -        acb->common.cb(acb->common.opaque, -EIO);
 -        qemu_aio_unref(acb);
 -        return;
 +        ret = -EIO;
 +        goto out;
      }
      acb->start = 0;
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
      state->orig_buf = g_try_malloc(state->buf_len);
      if (state->buf_len && state->orig_buf == NULL) {
          curl_clean_state(state);
 -        acb->common.cb(acb->common.opaque, -ENOMEM);
 -        qemu_aio_unref(acb);
 -        return;
 +        ret = -ENOMEM;
 +        goto out;
      }
      state->acb[0] = acb;
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
      /* Tell curl it needs to kick things off */
      curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
 +
 +out:
 +    if (ret != -EINPROGRESS) {
 +        acb->common.cb(acb->common.opaque, ret);
 +        qemu_aio_unref(acb);
 +    }
 +    aio_context_release(ctx);
  }
  static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,
 diff --git a/block/gluster.c b/block/gluster.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/gluster.c
 +++ b/block/gluster.c
@@ -XXX,XX +XXX,XX @@ static struct glfs *qemu_gluster_init(BlockdevOptionsGluster *gconf,
      return qemu_gluster_glfs_init(gconf, errp);
  }
 -static void qemu_gluster_complete_aio(void *opaque)
 -{
 -    GlusterAIOCB *acb = (GlusterAIOCB *)opaque;
 -
 -    qemu_coroutine_enter(acb->coroutine);
 -}
 -
  /*
   * AIO callback routine called from GlusterFS thread.
   */
@@ -XXX,XX +XXX,XX @@ static void gluster_finish_aiocb(struct glfs_fd *fd, ssize_t ret, void *arg)
          acb->ret = -EIO; /* Partial read/write - fail it */
      }
 -    aio_bh_schedule_oneshot(acb->aio_context, qemu_gluster_complete_aio, acb);
 +    aio_co_schedule(acb->aio_context, acb->coroutine);
  }
  static void qemu_gluster_parse_flags(int bdrv_flags, int *open_flags)
 diff --git a/block/io.c b/block/io.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/io.c
 +++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ static void bdrv_co_drain_bh_cb(void *opaque)
      bdrv_dec_in_flight(bs);
      bdrv_drained_begin(bs);
      data->done = true;
 -    qemu_coroutine_enter(co);
 +    aio_co_wake(co);
  }
  static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)
@@ -XXX,XX +XXX,XX @@ static void bdrv_co_complete(BlockAIOCBCoroutine *acb)
  static void bdrv_co_em_bh(void *opaque)
  {
      BlockAIOCBCoroutine *acb = opaque;
 +    BlockDriverState *bs = acb->common.bs;
 +    AioContext *ctx = bdrv_get_aio_context(bs);
      assert(!acb->need_bh);
 +    aio_context_acquire(ctx);
      bdrv_co_complete(acb);
 +    aio_context_release(ctx);
  }
  static void bdrv_co_maybe_schedule_bh(BlockAIOCBCoroutine *acb)
 diff --git a/block/iscsi.c b/block/iscsi.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/iscsi.c
 +++ b/block/iscsi.c
@@ -XXX,XX +XXX,XX @@ static void
  iscsi_bh_cb(void *p)
  {
      IscsiAIOCB *acb = p;
 +    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
      qemu_bh_delete(acb->bh);
      g_free(acb->buf);
      acb->buf = NULL;
 +    aio_context_acquire(ctx);
      acb->common.cb(acb->common.opaque, acb->status);
 +    aio_context_release(ctx);
      if (acb->task != NULL) {
          scsi_free_scsi_task(acb->task);
@@ -XXX,XX +XXX,XX @@ iscsi_schedule_bh(IscsiAIOCB *acb)
  static void iscsi_co_generic_bh_cb(void *opaque)
  {
      struct IscsiTask *iTask = opaque;
 +
      iTask->complete = 1;
 -    qemu_coroutine_enter(iTask->co);
 +    aio_co_wake(iTask->co);
  }
  static void iscsi_retry_timer_expired(void *opaque)
 diff --git a/block/linux-aio.c b/block/linux-aio.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/linux-aio.c
 +++ b/block/linux-aio.c
@@ -XXX,XX +XXX,XX @@ struct LinuxAioState {
      io_context_t ctx;
      EventNotifier e;
 -    /* io queue for submit at batch */
 +    /* io queue for submit at batch.  Protected by AioContext lock. */
      LaioQueue io_q;
 -    /* I/O completion processing */
 +    /* I/O completion processing.  Only runs in I/O thread.  */
      QEMUBH *completion_bh;
      int event_idx;
      int event_max;
@@ -XXX,XX +XXX,XX @@ static inline ssize_t io_event_ret(struct io_event *ev)
   */
  static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
  {
 +    LinuxAioState *s = laiocb->ctx;
      int ret;
      ret = laiocb->ret;
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
      }
      laiocb->ret = ret;
 +    aio_context_acquire(s->aio_context);
      if (laiocb->co) {
          /* If the coroutine is already entered it must be in ioq_submit() and
           * will notice laio->ret has been filled in when it eventually runs
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
          laiocb->common.cb(laiocb->common.opaque, ret);
          qemu_aio_unref(laiocb);
      }
 +    aio_context_release(s->aio_context);
  }
  /**
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completions(LinuxAioState *s)
  static void qemu_laio_process_completions_and_submit(LinuxAioState *s)
  {
      qemu_laio_process_completions(s);
 +
 +    aio_context_acquire(s->aio_context);
      if (!s->io_q.plugged && !QSIMPLEQ_EMPTY(&s->io_q.pending)) {
          ioq_submit(s);
      }
 +    aio_context_release(s->aio_context);
  }
  static void qemu_laio_completion_bh(void *opaque)
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_completion_cb(EventNotifier *e)
      LinuxAioState *s = container_of(e, LinuxAioState, e);
      if (event_notifier_test_and_clear(&s->e)) {
 -        aio_context_acquire(s->aio_context);
          qemu_laio_process_completions_and_submit(s);
 -        aio_context_release(s->aio_context);
      }
  }
-@@ -XXX,XX +XXX,XX @@ static bool qemu_laio_poll_cb(void *opaque)
++static void job_completed(Job *job);
-         return false;
++
  static void job_exit(void *opaque)
  {
      Job *job = (Job *)opaque;
@@ -XXX,XX +XXX,XX @@ static void job_exit(void *opaque)
          job->driver->exit(job);
          aio_context_release(aio_context);
      }
+-    job_completed(job, job->ret);
--    aio_context_acquire(s->aio_context);
++    job_completed(job);
      qemu_laio_process_completions_and_submit(s);
 -    aio_context_release(s->aio_context);
      return true;
  }
-@@ -XXX,XX +XXX,XX @@ void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context)
+ /**
- {
+@@ -XXX,XX +XXX,XX @@ static void job_completed_txn_success(Job *job)
      aio_set_event_notifier(old_context, &s->e, false, NULL, NULL);
      qemu_bh_delete(s->completion_bh);
 +    s->aio_context = NULL;
  }
  void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context)
 diff --git a/block/nfs.c b/block/nfs.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/nfs.c
 +++ b/block/nfs.c
@@ -XXX,XX +XXX,XX @@ static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
  static void nfs_co_generic_bh_cb(void *opaque)
  {
      NFSRPC *task = opaque;
 +
      task->complete = 1;
 -    qemu_coroutine_enter(task->co);
 +    aio_co_wake(task->co);
  }
  static void
 diff --git a/block/null.c b/block/null.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/null.c
 +++ b/block/null.c
@@ -XXX,XX +XXX,XX @@ static const AIOCBInfo null_aiocb_info = {
  static void null_bh_cb(void *opaque)
  {
      NullAIOCB *acb = opaque;
 +    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
 +
 +    aio_context_acquire(ctx);
      acb->common.cb(acb->common.opaque, 0);
 +    aio_context_release(ctx);
      qemu_aio_unref(acb);
  }
 diff --git a/block/qed.c b/block/qed.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/qed.c
 +++ b/block/qed.c
@@ -XXX,XX +XXX,XX @@ static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index,
  static void qed_aio_complete_bh(void *opaque)
  {
      QEDAIOCB *acb = opaque;
 +    BDRVQEDState *s = acb_to_s(acb);
      BlockCompletionFunc *cb = acb->common.cb;
      void *user_opaque = acb->common.opaque;
      int ret = acb->bh_ret;
@@ -XXX,XX +XXX,XX @@ static void qed_aio_complete_bh(void *opaque)
      qemu_aio_unref(acb);
      /* Invoke callback */
 +    qed_acquire(s);
      cb(user_opaque, ret);
 +    qed_release(s);
  }
  static void qed_aio_complete(QEDAIOCB *acb, int ret)
 diff --git a/block/rbd.c b/block/rbd.c
 index XXXXXXX..XXXXXXX 100644
 --- a/block/rbd.c
 +++ b/block/rbd.c
@@ -XXX,XX +XXX,XX @@ shutdown:
  static void qemu_rbd_complete_aio(RADOSCB *rcb)
  {
      RBDAIOCB *acb = rcb->acb;
 +    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
      int64_t r;
      r = rcb->ret;
@@ -XXX,XX +XXX,XX @@ static void qemu_rbd_complete_aio(RADOSCB *rcb)
          qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
      }
      qemu_vfree(acb->bounce);
 +
 +    aio_context_acquire(ctx);
      acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
 +    aio_context_release(ctx);
      qemu_aio_unref(acb);
  }
 diff --git a/dma-helpers.c b/dma-helpers.c
 index XXXXXXX..XXXXXXX 100644
 --- a/dma-helpers.c
 +++ b/dma-helpers.c
@@ -XXX,XX +XXX,XX @@ static void dma_blk_cb(void *opaque, int ret)
                                  QEMU_ALIGN_DOWN(dbs->iov.size, dbs->align));
      }
 +    aio_context_acquire(dbs->ctx);
      dbs->acb = dbs->io_func(dbs->offset, &dbs->iov,
                              dma_blk_cb, dbs, dbs->io_func_opaque);
 +    aio_context_release(dbs->ctx);
      assert(dbs->acb);
  }
 diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/block/virtio-blk.c
 +++ b/hw/block/virtio-blk.c
@@ -XXX,XX +XXX,XX @@ static void virtio_blk_dma_restart_bh(void *opaque)
      s->rq = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
      while (req) {
          VirtIOBlockReq *next = req->next;
          if (virtio_blk_handle_request(req, &mrb)) {
@@ -XXX,XX +XXX,XX @@ static void virtio_blk_dma_restart_bh(void *opaque)
      if (mrb.num_reqs) {
          virtio_blk_submit_multireq(s->blk, &mrb);
      }
 +    aio_context_release(blk_get_aio_context(s->conf.conf.blk));
  }
  static void virtio_blk_dma_restart_cb(void *opaque, int running,
 diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
 index XXXXXXX..XXXXXXX 100644
 --- a/hw/scsi/scsi-bus.c
 +++ b/hw/scsi/scsi-bus.c
@@ -XXX,XX +XXX,XX @@ static void scsi_dma_restart_bh(void *opaque)
      qemu_bh_delete(s->bh);
      s->bh = NULL;
 +    aio_context_acquire(blk_get_aio_context(s->conf.blk));
      QTAILQ_FOREACH_SAFE(req, &s->requests, next, next) {
          scsi_req_ref(req);
          if (req->retry) {
@@ -XXX,XX +XXX,XX @@ static void scsi_dma_restart_bh(void *opaque)
          }
          scsi_req_unref(req);
      }
 +    aio_context_release(blk_get_aio_context(s->conf.blk));
  }
  void scsi_req_retry(SCSIRequest *req)
 diff --git a/util/async.c b/util/async.c
 index XXXXXXX..XXXXXXX 100644
 --- a/util/async.c
 +++ b/util/async.c
@@ -XXX,XX +XXX,XX @@ int aio_bh_poll(AioContext *ctx)
                  ret = 1;
              }
              bh->idle = 0;
 -            aio_context_acquire(ctx);
              aio_bh_call(bh);
 -            aio_context_release(ctx);
          }
          if (bh->deleted) {
              deleted = true;
@@ -XXX,XX +XXX,XX @@ static void co_schedule_bh_cb(void *opaque)
          Coroutine *co = QSLIST_FIRST(&straight);
          QSLIST_REMOVE_HEAD(&straight, co_scheduled_next);
          trace_aio_co_schedule_bh_cb(ctx, co);
 +        aio_context_acquire(ctx);
          qemu_coroutine_enter(co);
 +        aio_context_release(ctx);
      }
  }
-diff --git a/util/thread-pool.c b/util/thread-pool.c
+-void job_completed(Job *job, int ret)
 +static void job_completed(Job *job)
  {
      assert(job && job->txn && !job_is_completed(job));
 -    job->ret = ret;
      job_update_rc(job);
 -    trace_job_completed(job, ret, job->ret);
 +    trace_job_completed(job, job->ret);
      if (job->ret) {
          job_completed_txn_abort(job);
      } else {
@@ -XXX,XX +XXX,XX @@ void job_cancel(Job *job, bool force)
      }
      job_cancel_async(job, force);
      if (!job_started(job)) {
 -        job_completed(job, -ECANCELED);
 +        job_completed(job);
      } else if (job->deferred_to_main_loop) {
          job_completed_txn_abort(job);
      } else {
 diff --git a/trace-events b/trace-events
 index XXXXXXX..XXXXXXX 100644
---- a/util/thread-pool.c
+--- a/trace-events
-+++ b/util/thread-pool.c
++++ b/trace-events
-@@ -XXX,XX +XXX,XX @@ static void thread_pool_completion_bh(void *opaque)
+@@ -XXX,XX +XXX,XX @@ gdbstub_err_checksum_incorrect(uint8_t expected, uint8_t got) "got command packe
-     ThreadPool *pool = opaque;
+ # job.c
-     ThreadPoolElement *elem, *next;
+ job_state_transition(void *job,  int ret, const char *legal, const char *s0, const char *s1) "job %p (ret: %d) attempting %s transition (%s-->%s)"
+ job_apply_verb(void *job, const char *state, const char *verb, const char *legal) "job %p in state %s; applying verb %s (%s)"
-+    aio_context_acquire(pool->ctx);
+-job_completed(void *job, int ret, int jret) "job %p ret %d corrected ret %d"
- restart:
++job_completed(void *job, int ret) "job %p ret %d"
-     QLIST_FOREACH_SAFE(elem, &pool->head, all, next) {
-         if (elem->state != THREAD_DONE) {
+ # job-qmp.c
-@@ -XXX,XX +XXX,XX @@ restart:
+ qmp_job_cancel(void *job) "job %p"
              qemu_aio_unref(elem);
          }
      }
 +    aio_context_release(pool->ctx);
  }
  static void thread_pool_cancel(BlockAIOCB *acb)
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 07/24] nbd: convert to use qio_channel_yield
+[Qemu-devel] [PULL v2 10/10] jobs: remove job_defer_to_main_loop
-From: Paolo Bonzini <pbonzini@redhat.com>
+From: John Snow <jsnow@redhat.com>
-In the client, read the reply headers from a coroutine, switching the
+Now that the job infrastructure is handling the job_completed call for
-read side between the "read header" coroutine and the I/O coroutine that
+all implemented jobs, we can remove the interface that allowed jobs to
-reads the body of the reply.
+schedule their own completion.
-In the server, if the server can read more requests it will create a new
+Signed-off-by: John Snow <jsnow@redhat.com>
-"read request" coroutine as soon as a request has been read.  Otherwise,
+Reviewed-by: Max Reitz <mreitz@redhat.com>
-the new coroutine is created in nbd_request_put.
+Message-id: 20180830015734.19765-10-jsnow@redhat.com
 Signed-off-by: Max Reitz <mreitz@redhat.com>
 ---
  include/qemu/job.h | 17 -----------------
  job.c              | 40 ++--------------------------------------
 files changed, 2 insertions(+), 55 deletions(-)
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
+diff --git a/include/qemu/job.h b/include/qemu/job.h
 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
 Reviewed-by: Fam Zheng <famz@redhat.com>
 Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
 Message-id: 20170213135235.12274-8-pbonzini@redhat.com
 Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
 ---
  block/nbd-client.h |   2 +-
  block/nbd-client.c | 117 ++++++++++++++++++++++++-----------------------------
  nbd/client.c       |   2 +-
  nbd/common.c       |   9 +----
  nbd/server.c       |  94 +++++++++++++-----------------------------
 files changed, 83 insertions(+), 141 deletions(-)
 diff --git a/block/nbd-client.h b/block/nbd-client.h
 index XXXXXXX..XXXXXXX 100644
---- a/block/nbd-client.h
+--- a/include/qemu/job.h
-+++ b/block/nbd-client.h
++++ b/include/qemu/job.h
-@@ -XXX,XX +XXX,XX @@ typedef struct NBDClientSession {
+@@ -XXX,XX +XXX,XX @@ void job_finalize(Job *job, Error **errp);
+  */
-     CoMutex send_mutex;
+ void job_dismiss(Job **job, Error **errp);
-     CoQueue free_sema;
--    Coroutine *send_coroutine;
+-typedef void JobDeferToMainLoopFn(Job *job, void *opaque);
-+    Coroutine *read_reply_co;
+-
-     int in_flight;
+-/**
+- * @job: The job
-     Coroutine *recv_coroutine[MAX_NBD_REQUESTS];
+- * @fn: The function to run in the main loop
-diff --git a/block/nbd-client.c b/block/nbd-client.c
+- * @opaque: The opaque value that is passed to @fn
 - *
 - * This function must be called by the main job coroutine just before it
 - * returns.  @fn is executed in the main loop with the job AioContext acquired.
 - *
 - * Block jobs must call bdrv_unref(), bdrv_close(), and anything that uses
 - * bdrv_drain_all() in the main loop.
 - *
 - * The @job AioContext is held while @fn executes.
 - */
 -void job_defer_to_main_loop(Job *job, JobDeferToMainLoopFn *fn, void *opaque);
 -
  /**
   * Synchronously finishes the given @job. If @finish is given, it is called to
   * trigger completion or cancellation of the job.
 diff --git a/job.c b/job.c
 index XXXXXXX..XXXXXXX 100644
---- a/block/nbd-client.c
+--- a/job.c
-+++ b/block/nbd-client.c
++++ b/job.c
-@@ -XXX,XX +XXX,XX @@
+@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)
- #define HANDLE_TO_INDEX(bs, handle) ((handle) ^ ((uint64_t)(intptr_t)bs))
+     assert(job && job->driver && job->driver->run);
- #define INDEX_TO_HANDLE(bs, index)  ((index)  ^ ((uint64_t)(intptr_t)bs))
+     job_pause_point(job);
+     job->ret = job->driver->run(job, &job->err);
--static void nbd_recv_coroutines_enter_all(NBDClientSession *s)
+-    if (!job->deferred_to_main_loop) {
-+static void nbd_recv_coroutines_enter_all(BlockDriverState *bs)
+-        job->deferred_to_main_loop = true;
- {
+-        aio_bh_schedule_oneshot(qemu_get_aio_context(),
-+    NBDClientSession *s = nbd_get_client_session(bs);
+-                                job_exit,
-     int i;
+-                                job);
+-    }
-     for (i = 0; i < MAX_NBD_REQUESTS; i++) {
++    job->deferred_to_main_loop = true;
-@@ -XXX,XX +XXX,XX @@ static void nbd_recv_coroutines_enter_all(NBDClientSession *s)
++    aio_bh_schedule_oneshot(qemu_get_aio_context(), job_exit, job);
              qemu_coroutine_enter(s->recv_coroutine[i]);
          }
      }
 +    BDRV_POLL_WHILE(bs, s->read_reply_co);
  }
- static void nbd_teardown_connection(BlockDriverState *bs)
-@@ -XXX,XX +XXX,XX @@ static void nbd_teardown_connection(BlockDriverState *bs)
+@@ -XXX,XX +XXX,XX @@ void job_complete(Job *job, Error **errp)
-     qio_channel_shutdown(client->ioc,
+     job->driver->complete(job, errp);
                           QIO_CHANNEL_SHUTDOWN_BOTH,
                           NULL);
 -    nbd_recv_coroutines_enter_all(client);
 +    nbd_recv_coroutines_enter_all(bs);
      nbd_client_detach_aio_context(bs);
      object_unref(OBJECT(client->sioc));
@@ -XXX,XX +XXX,XX @@ static void nbd_teardown_connection(BlockDriverState *bs)
      client->ioc = NULL;
  }
--static void nbd_reply_ready(void *opaque)
-+static coroutine_fn void nbd_read_reply_entry(void *opaque)
- {
--    BlockDriverState *bs = opaque;
--    NBDClientSession *s = nbd_get_client_session(bs);
-+    NBDClientSession *s = opaque;
-     uint64_t i;
-     int ret;
--    if (!s->ioc) { /* Already closed */
--        return;
--    }
 -
--    if (s->reply.handle == 0) {
+-typedef struct {
--        /* No reply already in flight.  Fetch a header.  It is possible
+-    Job *job;
--         * that another thread has done the same thing in parallel, so
+-    JobDeferToMainLoopFn *fn;
--         * the socket is not readable anymore.
+-    void *opaque;
--         */
+-} JobDeferToMainLoopData;
 +    for (;;) {
 +        assert(s->reply.handle == 0);
          ret = nbd_receive_reply(s->ioc, &s->reply);
 -        if (ret == -EAGAIN) {
 -            return;
 -        }
          if (ret < 0) {
 -            s->reply.handle = 0;
 -            goto fail;
 +            break;
          }
 -    }
 -    /* There's no need for a mutex on the receive side, because the
 -     * handler acts as a synchronization point and ensures that only
 -     * one coroutine is called until the reply finishes.  */
 -    i = HANDLE_TO_INDEX(s, s->reply.handle);
 -    if (i >= MAX_NBD_REQUESTS) {
 -        goto fail;
 -    }
 +        /* There's no need for a mutex on the receive side, because the
 +         * handler acts as a synchronization point and ensures that only
 +         * one coroutine is called until the reply finishes.
 +         */
 +        i = HANDLE_TO_INDEX(s, s->reply.handle);
 +        if (i >= MAX_NBD_REQUESTS || !s->recv_coroutine[i]) {
 +            break;
 +        }
 -    if (s->recv_coroutine[i]) {
 -        qemu_coroutine_enter(s->recv_coroutine[i]);
 -        return;
 +        /* We're woken up by the recv_coroutine itself.  Note that there
 +         * is no race between yielding and reentering read_reply_co.  This
 +         * is because:
 +         *
 +         * - if recv_coroutine[i] runs on the same AioContext, it is only
 +         *   entered after we yield
 +         *
 +         * - if recv_coroutine[i] runs on a different AioContext, reentering
 +         *   read_reply_co happens through a bottom half, which can only
 +         *   run after we yield.
 +         */
 +        aio_co_wake(s->recv_coroutine[i]);
 +        qemu_coroutine_yield();
      }
 -
--fail:
+-static void job_defer_to_main_loop_bh(void *opaque)
--    nbd_teardown_connection(bs);
+-{
 -    JobDeferToMainLoopData *data = opaque;
 -    Job *job = data->job;
 -    AioContext *aio_context = job->aio_context;
 -
 -    aio_context_acquire(aio_context);
 -    data->fn(data->job, data->opaque);
 -    aio_context_release(aio_context);
 -
 -    g_free(data);
 -}
 -
--static void nbd_restart_write(void *opaque)
+-void job_defer_to_main_loop(Job *job, JobDeferToMainLoopFn *fn, void *opaque)
 -{
--    BlockDriverState *bs = opaque;
+-    JobDeferToMainLoopData *data = g_malloc(sizeof(*data));
 -    data->job = job;
 -    data->fn = fn;
 -    data->opaque = opaque;
 -    job->deferred_to_main_loop = true;
 -
--    qemu_coroutine_enter(nbd_get_client_session(bs)->send_coroutine);
+-    aio_bh_schedule_oneshot(qemu_get_aio_context(),
-+    s->read_reply_co = NULL;
+-                            job_defer_to_main_loop_bh, data);
  }
  static int nbd_co_send_request(BlockDriverState *bs,
@@ -XXX,XX +XXX,XX @@ static int nbd_co_send_request(BlockDriverState *bs,
                                 QEMUIOVector *qiov)
  {
      NBDClientSession *s = nbd_get_client_session(bs);
 -    AioContext *aio_context;
      int rc, ret, i;
      qemu_co_mutex_lock(&s->send_mutex);
@@ -XXX,XX +XXX,XX @@ static int nbd_co_send_request(BlockDriverState *bs,
          return -EPIPE;
      }
 -    s->send_coroutine = qemu_coroutine_self();
 -    aio_context = bdrv_get_aio_context(bs);
 -
 -    aio_set_fd_handler(aio_context, s->sioc->fd, false,
 -                       nbd_reply_ready, nbd_restart_write, NULL, bs);
      if (qiov) {
          qio_channel_set_cork(s->ioc, true);
          rc = nbd_send_request(s->ioc, request);
@@ -XXX,XX +XXX,XX @@ static int nbd_co_send_request(BlockDriverState *bs,
      } else {
          rc = nbd_send_request(s->ioc, request);
      }
 -    aio_set_fd_handler(aio_context, s->sioc->fd, false,
 -                       nbd_reply_ready, NULL, NULL, bs);
 -    s->send_coroutine = NULL;
      qemu_co_mutex_unlock(&s->send_mutex);
      return rc;
  }
@@ -XXX,XX +XXX,XX @@ static void nbd_co_receive_reply(NBDClientSession *s,
  {
      int ret;
 -    /* Wait until we're woken up by the read handler.  TODO: perhaps
 -     * peek at the next reply and avoid yielding if it's ours?  */
 +    /* Wait until we're woken up by nbd_read_reply_entry.  */
      qemu_coroutine_yield();
      *reply = s->reply;
      if (reply->handle != request->handle ||
@@ -XXX,XX +XXX,XX @@ static void nbd_coroutine_start(NBDClientSession *s,
      /* s->recv_coroutine[i] is set as soon as we get the send_lock.  */
  }
 -static void nbd_coroutine_end(NBDClientSession *s,
 +static void nbd_coroutine_end(BlockDriverState *bs,
                                NBDRequest *request)
  {
 +    NBDClientSession *s = nbd_get_client_session(bs);
      int i = HANDLE_TO_INDEX(s, request->handle);
 +
      s->recv_coroutine[i] = NULL;
 -    if (s->in_flight-- == MAX_NBD_REQUESTS) {
 -        qemu_co_queue_next(&s->free_sema);
 +    s->in_flight--;
 +    qemu_co_queue_next(&s->free_sema);
 +
 +    /* Kick the read_reply_co to get the next reply.  */
 +    if (s->read_reply_co) {
 +        aio_co_wake(s->read_reply_co);
      }
  }
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
      } else {
          nbd_co_receive_reply(client, &request, &reply, qiov);
      }
 -    nbd_coroutine_end(client, &request);
 +    nbd_coroutine_end(bs, &request);
      return -reply.error;
  }
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
      } else {
          nbd_co_receive_reply(client, &request, &reply, NULL);
      }
 -    nbd_coroutine_end(client, &request);
 +    nbd_coroutine_end(bs, &request);
      return -reply.error;
  }
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
      } else {
          nbd_co_receive_reply(client, &request, &reply, NULL);
      }
 -    nbd_coroutine_end(client, &request);
 +    nbd_coroutine_end(bs, &request);
      return -reply.error;
  }
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_flush(BlockDriverState *bs)
      } else {
          nbd_co_receive_reply(client, &request, &reply, NULL);
      }
 -    nbd_coroutine_end(client, &request);
 +    nbd_coroutine_end(bs, &request);
      return -reply.error;
  }
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, int count)
      } else {
          nbd_co_receive_reply(client, &request, &reply, NULL);
      }
 -    nbd_coroutine_end(client, &request);
 +    nbd_coroutine_end(bs, &request);
      return -reply.error;
  }
  void nbd_client_detach_aio_context(BlockDriverState *bs)
  {
 -    aio_set_fd_handler(bdrv_get_aio_context(bs),
 -                       nbd_get_client_session(bs)->sioc->fd,
 -                       false, NULL, NULL, NULL, NULL);
 +    NBDClientSession *client = nbd_get_client_session(bs);
 +    qio_channel_detach_aio_context(QIO_CHANNEL(client->sioc));
  }
  void nbd_client_attach_aio_context(BlockDriverState *bs,
                                     AioContext *new_context)
  {
 -    aio_set_fd_handler(new_context, nbd_get_client_session(bs)->sioc->fd,
 -                       false, nbd_reply_ready, NULL, NULL, bs);
 +    NBDClientSession *client = nbd_get_client_session(bs);
 +    qio_channel_attach_aio_context(QIO_CHANNEL(client->sioc), new_context);
 +    aio_co_schedule(new_context, client->read_reply_co);
  }
  void nbd_client_close(BlockDriverState *bs)
@@ -XXX,XX +XXX,XX @@ int nbd_client_init(BlockDriverState *bs,
      /* Now that we're connected, set the socket to be non-blocking and
       * kick the reply mechanism.  */
      qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
 -
 +    client->read_reply_co = qemu_coroutine_create(nbd_read_reply_entry, client);
      nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs));
      logout("Established connection with NBD server\n");
 diff --git a/nbd/client.c b/nbd/client.c
 index XXXXXXX..XXXXXXX 100644
 --- a/nbd/client.c
 +++ b/nbd/client.c
@@ -XXX,XX +XXX,XX @@ ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply *reply)
      ssize_t ret;
      ret = read_sync(ioc, buf, sizeof(buf));
 -    if (ret < 0) {
 +    if (ret <= 0) {
          return ret;
      }
 diff --git a/nbd/common.c b/nbd/common.c
 index XXXXXXX..XXXXXXX 100644
 --- a/nbd/common.c
 +++ b/nbd/common.c
@@ -XXX,XX +XXX,XX @@ ssize_t nbd_wr_syncv(QIOChannel *ioc,
          }
          if (len == QIO_CHANNEL_ERR_BLOCK) {
              if (qemu_in_coroutine()) {
 -                /* XXX figure out if we can create a variant on
 -                 * qio_channel_yield() that works with AIO contexts
 -                 * and consider using that in this branch */
 -                qemu_coroutine_yield();
 -            } else if (done) {
 -                /* XXX this is needed by nbd_reply_ready.  */
 -                qio_channel_wait(ioc,
 -                                 do_read ? G_IO_IN : G_IO_OUT);
 +                qio_channel_yield(ioc, do_read ? G_IO_IN : G_IO_OUT);
              } else {
                  return -EAGAIN;
              }
 diff --git a/nbd/server.c b/nbd/server.c
 index XXXXXXX..XXXXXXX 100644
 --- a/nbd/server.c
 +++ b/nbd/server.c
@@ -XXX,XX +XXX,XX @@ struct NBDClient {
      CoMutex send_lock;
      Coroutine *send_coroutine;
 -    bool can_read;
 -
      QTAILQ_ENTRY(NBDClient) next;
      int nb_requests;
      bool closing;
@@ -XXX,XX +XXX,XX @@ struct NBDClient {
  /* That's all folks */
 -static void nbd_set_handlers(NBDClient *client);
 -static void nbd_unset_handlers(NBDClient *client);
 -static void nbd_update_can_read(NBDClient *client);
 +static void nbd_client_receive_next_request(NBDClient *client);
  static gboolean nbd_negotiate_continue(QIOChannel *ioc,
                                         GIOCondition condition,
@@ -XXX,XX +XXX,XX @@ void nbd_client_put(NBDClient *client)
           */
          assert(client->closing);
 -        nbd_unset_handlers(client);
 +        qio_channel_detach_aio_context(client->ioc);
          object_unref(OBJECT(client->sioc));
          object_unref(OBJECT(client->ioc));
          if (client->tlscreds) {
@@ -XXX,XX +XXX,XX @@ static NBDRequestData *nbd_request_get(NBDClient *client)
      assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
      client->nb_requests++;
 -    nbd_update_can_read(client);
      req = g_new0(NBDRequestData, 1);
      nbd_client_get(client);
@@ -XXX,XX +XXX,XX @@ static void nbd_request_put(NBDRequestData *req)
      g_free(req);
      client->nb_requests--;
 -    nbd_update_can_read(client);
 +    nbd_client_receive_next_request(client);
 +
      nbd_client_put(client);
  }
@@ -XXX,XX +XXX,XX @@ static void blk_aio_attached(AioContext *ctx, void *opaque)
      exp->ctx = ctx;
      QTAILQ_FOREACH(client, &exp->clients, next) {
 -        nbd_set_handlers(client);
 +        qio_channel_attach_aio_context(client->ioc, ctx);
 +        if (client->recv_coroutine) {
 +            aio_co_schedule(ctx, client->recv_coroutine);
 +        }
 +        if (client->send_coroutine) {
 +            aio_co_schedule(ctx, client->send_coroutine);
 +        }
      }
  }
@@ -XXX,XX +XXX,XX @@ static void blk_aio_detach(void *opaque)
      TRACE("Export %s: Detaching clients from AIO context %p\n", exp->name, exp->ctx);
      QTAILQ_FOREACH(client, &exp->clients, next) {
 -        nbd_unset_handlers(client);
 +        qio_channel_detach_aio_context(client->ioc);
      }
      exp->ctx = NULL;
@@ -XXX,XX +XXX,XX @@ static ssize_t nbd_co_send_reply(NBDRequestData *req, NBDReply *reply,
      g_assert(qemu_in_coroutine());
      qemu_co_mutex_lock(&client->send_lock);
      client->send_coroutine = qemu_coroutine_self();
 -    nbd_set_handlers(client);
      if (!len) {
          rc = nbd_send_reply(client->ioc, reply);
@@ -XXX,XX +XXX,XX @@ static ssize_t nbd_co_send_reply(NBDRequestData *req, NBDReply *reply,
      }
      client->send_coroutine = NULL;
 -    nbd_set_handlers(client);
      qemu_co_mutex_unlock(&client->send_lock);
      return rc;
  }
@@ -XXX,XX +XXX,XX @@ static ssize_t nbd_co_receive_request(NBDRequestData *req,
      ssize_t rc;
      g_assert(qemu_in_coroutine());
 -    client->recv_coroutine = qemu_coroutine_self();
 -    nbd_update_can_read(client);
 -
 +    assert(client->recv_coroutine == qemu_coroutine_self());
      rc = nbd_receive_request(client->ioc, request);
      if (rc < 0) {
          if (rc != -EAGAIN) {
@@ -XXX,XX +XXX,XX @@ static ssize_t nbd_co_receive_request(NBDRequestData *req,
  out:
      client->recv_coroutine = NULL;
 -    nbd_update_can_read(client);
 +    nbd_client_receive_next_request(client);
      return rc;
  }
 -static void nbd_trip(void *opaque)
 +/* Owns a reference to the NBDClient passed as opaque.  */
 +static coroutine_fn void nbd_trip(void *opaque)
  {
      NBDClient *client = opaque;
      NBDExport *exp = client->exp;
      NBDRequestData *req;
 -    NBDRequest request;
 +    NBDRequest request = { 0 };    /* GCC thinks it can be used uninitialized */
      NBDReply reply;
      ssize_t ret;
      int flags;
      TRACE("Reading request.");
      if (client->closing) {
 +        nbd_client_put(client);
          return;
      }
@@ -XXX,XX +XXX,XX @@ static void nbd_trip(void *opaque)
  done:
      nbd_request_put(req);
 +    nbd_client_put(client);
      return;
  out:
      nbd_request_put(req);
      client_close(client);
 +    nbd_client_put(client);
  }
 -static void nbd_read(void *opaque)
 +static void nbd_client_receive_next_request(NBDClient *client)
  {
 -    NBDClient *client = opaque;
 -
 -    if (client->recv_coroutine) {
 -        qemu_coroutine_enter(client->recv_coroutine);
 -    } else {
 -        qemu_coroutine_enter(qemu_coroutine_create(nbd_trip, client));
 -    }
 -}
 -
--static void nbd_restart_write(void *opaque)
+ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
--{
+ {
--    NBDClient *client = opaque;
+     Error *local_err = NULL;
 -
 -    qemu_coroutine_enter(client->send_coroutine);
 -}
 -
 -static void nbd_set_handlers(NBDClient *client)
 -{
 -    if (client->exp && client->exp->ctx) {
 -        aio_set_fd_handler(client->exp->ctx, client->sioc->fd, true,
 -                           client->can_read ? nbd_read : NULL,
 -                           client->send_coroutine ? nbd_restart_write : NULL,
 -                           NULL, client);
 -    }
 -}
 -
 -static void nbd_unset_handlers(NBDClient *client)
 -{
 -    if (client->exp && client->exp->ctx) {
 -        aio_set_fd_handler(client->exp->ctx, client->sioc->fd, true, NULL,
 -                           NULL, NULL, NULL);
 -    }
 -}
 -
 -static void nbd_update_can_read(NBDClient *client)
 -{
 -    bool can_read = client->recv_coroutine ||
 -                    client->nb_requests < MAX_NBD_REQUESTS;
 -
 -    if (can_read != client->can_read) {
 -        client->can_read = can_read;
 -        nbd_set_handlers(client);
 -
 -        /* There is no need to invoke aio_notify(), since aio_set_fd_handler()
 -         * in nbd_set_handlers() will have taken care of that */
 +    if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
 +        nbd_client_get(client);
 +        client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
 +        aio_co_schedule(client->exp->ctx, client->recv_coroutine);
      }
  }
@@ -XXX,XX +XXX,XX @@ static coroutine_fn void nbd_co_client_start(void *opaque)
          goto out;
      }
      qemu_co_mutex_init(&client->send_lock);
 -    nbd_set_handlers(client);
      if (exp) {
          QTAILQ_INSERT_TAIL(&exp->clients, client, next);
      }
 +
 +    nbd_client_receive_next_request(client);
 +
  out:
      g_free(data);
  }
@@ -XXX,XX +XXX,XX @@ void nbd_client_new(NBDExport *exp,
      object_ref(OBJECT(client->sioc));
      client->ioc = QIO_CHANNEL(sioc);
      object_ref(OBJECT(client->ioc));
 -    client->can_read = true;
      client->close = close_fn;
      data->client = client;
 --
-.9.3
+.17.1

-[Qemu-devel] [PULL v2 08/24] coroutine-lock: reschedule coroutine on the AioContext it was running on
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-As a small step towards the introduction of multiqueue, we want
-coroutines to remain on the same AioContext that started them,
-unless they are moved explicitly with e.g. aio_co_schedule.  This patch
-avoids that coroutines switch AioContext when they use a CoMutex.
-For now it does not make much of a difference, because the CoMutex
-is not thread-safe and the AioContext itself is used to protect the
-CoMutex from concurrent access.  However, this is going to change.
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
-Message-id: 20170213135235.12274-9-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- util/qemu-coroutine-lock.c | 5 ++---
- util/trace-events          | 1 -
-files changed, 2 insertions(+), 4 deletions(-)
-diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/qemu-coroutine-lock.c
-+++ b/util/qemu-coroutine-lock.c
-@@ -XXX,XX +XXX,XX @@
- #include "qemu/coroutine.h"
- #include "qemu/coroutine_int.h"
- #include "qemu/queue.h"
-+#include "block/aio.h"
- #include "trace.h"
- void qemu_co_queue_init(CoQueue *queue)
-@@ -XXX,XX +XXX,XX @@ void qemu_co_queue_run_restart(Coroutine *co)
- static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
- {
--    Coroutine *self = qemu_coroutine_self();
-     Coroutine *next;
-     if (QSIMPLEQ_EMPTY(&queue->entries)) {
-@@ -XXX,XX +XXX,XX @@ static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
-     while ((next = QSIMPLEQ_FIRST(&queue->entries)) != NULL) {
-         QSIMPLEQ_REMOVE_HEAD(&queue->entries, co_queue_next);
--        QSIMPLEQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next);
--        trace_qemu_co_queue_next(next);
-+        aio_co_wake(next);
-         if (single) {
-             break;
-         }
-diff --git a/util/trace-events b/util/trace-events
-index XXXXXXX..XXXXXXX 100644
---- a/util/trace-events
-+++ b/util/trace-events
-@@ -XXX,XX +XXX,XX @@ qemu_coroutine_terminate(void *co) "self %p"
- # util/qemu-coroutine-lock.c
- qemu_co_queue_run_restart(void *co) "co %p"
--qemu_co_queue_next(void *nxt) "next %p"
- qemu_co_mutex_lock_entry(void *mutex, void *self) "mutex %p self %p"
- qemu_co_mutex_lock_return(void *mutex, void *self) "mutex %p self %p"
- qemu_co_mutex_unlock_entry(void *mutex, void *self) "mutex %p self %p"
---
-.9.3

-[Qemu-devel] [PULL v2 11/24] aio: push aio_context_acquire/release down to dispatching
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-The AioContext data structures are now protected by list_lock and/or
-they are walked with FOREACH_RCU primitives.  There is no need anymore
-to acquire the AioContext for the entire duration of aio_dispatch.
-Instead, just acquire it before and after invoking the callbacks.
-The next step is then to push it further down.
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
-Message-id: 20170213135235.12274-12-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- util/aio-posix.c | 25 +++++++++++--------------
- util/aio-win32.c | 15 +++++++--------
- util/async.c     |  2 ++
-files changed, 20 insertions(+), 22 deletions(-)
-diff --git a/util/aio-posix.c b/util/aio-posix.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/aio-posix.c
-+++ b/util/aio-posix.c
-@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
-             (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) &&
-             aio_node_check(ctx, node->is_external) &&
-             node->io_read) {
-+            aio_context_acquire(ctx);
-             node->io_read(node->opaque);
-+            aio_context_release(ctx);
-             /* aio_notify() does not count as progress */
-             if (node->opaque != &ctx->notifier) {
-@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
-             (revents & (G_IO_OUT | G_IO_ERR)) &&
-             aio_node_check(ctx, node->is_external) &&
-             node->io_write) {
-+            aio_context_acquire(ctx);
-             node->io_write(node->opaque);
-+            aio_context_release(ctx);
-             progress = true;
-         }
-@@ -XXX,XX +XXX,XX @@ bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
-     }
-     /* Run our timers */
-+    aio_context_acquire(ctx);
-     progress |= timerlistgroup_run_timers(&ctx->tlg);
-+    aio_context_release(ctx);
-     return progress;
- }
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
-     int64_t timeout;
-     int64_t start = 0;
--    aio_context_acquire(ctx);
--    progress = false;
--
-     /* aio_notify can avoid the expensive event_notifier_set if
-      * everything (file descriptors, bottom halves, timers) will
-      * be re-evaluated before the next blocking poll().  This is
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
-         start = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
-     }
--    if (try_poll_mode(ctx, blocking)) {
--        progress = true;
--    } else {
-+    aio_context_acquire(ctx);
-+    progress = try_poll_mode(ctx, blocking);
-+    aio_context_release(ctx);
-+
-+    if (!progress) {
-         assert(npfd == 0);
-         /* fill pollfds */
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
-         timeout = blocking ? aio_compute_timeout(ctx) : 0;
-         /* wait until next event */
--        if (timeout) {
--            aio_context_release(ctx);
--        }
-         if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) {
-             AioHandler epoll_handler;
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
-         } else  {
-             ret = qemu_poll_ns(pollfds, npfd, timeout);
-         }
--        if (timeout) {
--            aio_context_acquire(ctx);
--        }
-     }
-     if (blocking) {
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
-         progress = true;
-     }
--    aio_context_release(ctx);
--
-     return progress;
- }
-diff --git a/util/aio-win32.c b/util/aio-win32.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/aio-win32.c
-+++ b/util/aio-win32.c
-@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
-             (revents || event_notifier_get_handle(node->e) == event) &&
-             node->io_notify) {
-             node->pfd.revents = 0;
-+            aio_context_acquire(ctx);
-             node->io_notify(node->e);
-+            aio_context_release(ctx);
-             /* aio_notify() does not count as progress */
-             if (node->e != &ctx->notifier) {
-@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
-             (node->io_read || node->io_write)) {
-             node->pfd.revents = 0;
-             if ((revents & G_IO_IN) && node->io_read) {
-+                aio_context_acquire(ctx);
-                 node->io_read(node->opaque);
-+                aio_context_release(ctx);
-                 progress = true;
-             }
-             if ((revents & G_IO_OUT) && node->io_write) {
-+                aio_context_acquire(ctx);
-                 node->io_write(node->opaque);
-+                aio_context_release(ctx);
-                 progress = true;
-             }
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
-     int count;
-     int timeout;
--    aio_context_acquire(ctx);
-     progress = false;
-     /* aio_notify can avoid the expensive event_notifier_set if
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
-         timeout = blocking && !have_select_revents
-             ? qemu_timeout_ns_to_ms(aio_compute_timeout(ctx)) : 0;
--        if (timeout) {
--            aio_context_release(ctx);
--        }
-         ret = WaitForMultipleObjects(count, events, FALSE, timeout);
-         if (blocking) {
-             assert(first);
-             atomic_sub(&ctx->notify_me, 2);
-         }
--        if (timeout) {
--            aio_context_acquire(ctx);
--        }
-         if (first) {
-             aio_notify_accept(ctx);
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
-         progress |= aio_dispatch_handlers(ctx, event);
-     } while (count > 0);
-+    aio_context_acquire(ctx);
-     progress |= timerlistgroup_run_timers(&ctx->tlg);
--
-     aio_context_release(ctx);
-     return progress;
- }
-diff --git a/util/async.c b/util/async.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/async.c
-+++ b/util/async.c
-@@ -XXX,XX +XXX,XX @@ int aio_bh_poll(AioContext *ctx)
-                 ret = 1;
-             }
-             bh->idle = 0;
-+            aio_context_acquire(ctx);
-             aio_bh_call(bh);
-+            aio_context_release(ctx);
-         }
-         if (bh->deleted) {
-             deleted = true;
---
-.9.3

-[Qemu-devel] [PULL v2 12/24] block: explicitly acquire aiocontext in timers that need it
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
-Message-id: 20170213135235.12274-13-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- block/qed.h                 |  3 +++
- block/curl.c                |  2 ++
- block/io.c                  |  5 +++++
- block/iscsi.c               |  8 ++++++--
- block/null.c                |  4 ++++
- block/qed.c                 | 12 ++++++++++++
- block/throttle-groups.c     |  2 ++
- util/aio-posix.c            |  2 --
- util/aio-win32.c            |  2 --
- util/qemu-coroutine-sleep.c |  2 +-
-files changed, 35 insertions(+), 7 deletions(-)
-diff --git a/block/qed.h b/block/qed.h
-index XXXXXXX..XXXXXXX 100644
---- a/block/qed.h
-+++ b/block/qed.h
-@@ -XXX,XX +XXX,XX @@ enum {
-  */
- typedef void QEDFindClusterFunc(void *opaque, int ret, uint64_t offset, size_t len);
-+void qed_acquire(BDRVQEDState *s);
-+void qed_release(BDRVQEDState *s);
-+
- /**
-  * Generic callback for chaining async callbacks
-  */
-diff --git a/block/curl.c b/block/curl.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/curl.c
-+++ b/block/curl.c
-@@ -XXX,XX +XXX,XX @@ static void curl_multi_timeout_do(void *arg)
-         return;
-     }
-+    aio_context_acquire(s->aio_context);
-     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
-     curl_multi_check_completion(s);
-+    aio_context_release(s->aio_context);
- #else
-     abort();
- #endif
-diff --git a/block/io.c b/block/io.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/io.c
-+++ b/block/io.c
-@@ -XXX,XX +XXX,XX @@ void bdrv_aio_cancel(BlockAIOCB *acb)
-         if (acb->aiocb_info->get_aio_context) {
-             aio_poll(acb->aiocb_info->get_aio_context(acb), true);
-         } else if (acb->bs) {
-+            /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so
-+             * assert that we're not using an I/O thread.  Thread-safe
-+             * code should use bdrv_aio_cancel_async exclusively.
-+             */
-+            assert(bdrv_get_aio_context(acb->bs) == qemu_get_aio_context());
-             aio_poll(bdrv_get_aio_context(acb->bs), true);
-         } else {
-             abort();
-diff --git a/block/iscsi.c b/block/iscsi.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/iscsi.c
-+++ b/block/iscsi.c
-@@ -XXX,XX +XXX,XX @@ static void iscsi_retry_timer_expired(void *opaque)
-     struct IscsiTask *iTask = opaque;
-     iTask->complete = 1;
-     if (iTask->co) {
--        qemu_coroutine_enter(iTask->co);
-+        aio_co_wake(iTask->co);
-     }
- }
-@@ -XXX,XX +XXX,XX @@ static void iscsi_nop_timed_event(void *opaque)
- {
-     IscsiLun *iscsilun = opaque;
-+    aio_context_acquire(iscsilun->aio_context);
-     if (iscsi_get_nops_in_flight(iscsilun->iscsi) >= MAX_NOP_FAILURES) {
-         error_report("iSCSI: NOP timeout. Reconnecting...");
-         iscsilun->request_timed_out = true;
-     } else if (iscsi_nop_out_async(iscsilun->iscsi, NULL, NULL, 0, NULL) != 0) {
-         error_report("iSCSI: failed to sent NOP-Out. Disabling NOP messages.");
--        return;
-+        goto out;
-     }
-     timer_mod(iscsilun->nop_timer, qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + NOP_INTERVAL);
-     iscsi_set_events(iscsilun);
-+
-+out:
-+    aio_context_release(iscsilun->aio_context);
- }
- static void iscsi_readcapacity_sync(IscsiLun *iscsilun, Error **errp)
-diff --git a/block/null.c b/block/null.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/null.c
-+++ b/block/null.c
-@@ -XXX,XX +XXX,XX @@ static void null_bh_cb(void *opaque)
- static void null_timer_cb(void *opaque)
- {
-     NullAIOCB *acb = opaque;
-+    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
-+
-+    aio_context_acquire(ctx);
-     acb->common.cb(acb->common.opaque, 0);
-+    aio_context_release(ctx);
-     timer_deinit(&acb->timer);
-     qemu_aio_unref(acb);
- }
-diff --git a/block/qed.c b/block/qed.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/qed.c
-+++ b/block/qed.c
-@@ -XXX,XX +XXX,XX @@ static void qed_need_check_timer_cb(void *opaque)
-     trace_qed_need_check_timer_cb(s);
-+    qed_acquire(s);
-     qed_plug_allocating_write_reqs(s);
-     /* Ensure writes are on disk before clearing flag */
-     bdrv_aio_flush(s->bs->file->bs, qed_clear_need_check, s);
-+    qed_release(s);
-+}
-+
-+void qed_acquire(BDRVQEDState *s)
-+{
-+    aio_context_acquire(bdrv_get_aio_context(s->bs));
-+}
-+
-+void qed_release(BDRVQEDState *s)
-+{
-+    aio_context_release(bdrv_get_aio_context(s->bs));
- }
- static void qed_start_need_check_timer(BDRVQEDState *s)
-diff --git a/block/throttle-groups.c b/block/throttle-groups.c
-index XXXXXXX..XXXXXXX 100644
---- a/block/throttle-groups.c
-+++ b/block/throttle-groups.c
-@@ -XXX,XX +XXX,XX @@ static void timer_cb(BlockBackend *blk, bool is_write)
-     qemu_mutex_unlock(&tg->lock);
-     /* Run the request that was waiting for this timer */
-+    aio_context_acquire(blk_get_aio_context(blk));
-     empty_queue = !qemu_co_enter_next(&blkp->throttled_reqs[is_write]);
-+    aio_context_release(blk_get_aio_context(blk));
-     /* If the request queue was empty then we have to take care of
-      * scheduling the next one */
-diff --git a/util/aio-posix.c b/util/aio-posix.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/aio-posix.c
-+++ b/util/aio-posix.c
-@@ -XXX,XX +XXX,XX @@ bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
-     }
-     /* Run our timers */
--    aio_context_acquire(ctx);
-     progress |= timerlistgroup_run_timers(&ctx->tlg);
--    aio_context_release(ctx);
-     return progress;
- }
-diff --git a/util/aio-win32.c b/util/aio-win32.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/aio-win32.c
-+++ b/util/aio-win32.c
-@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
-         progress |= aio_dispatch_handlers(ctx, event);
-     } while (count > 0);
--    aio_context_acquire(ctx);
-     progress |= timerlistgroup_run_timers(&ctx->tlg);
--    aio_context_release(ctx);
-     return progress;
- }
-diff --git a/util/qemu-coroutine-sleep.c b/util/qemu-coroutine-sleep.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/qemu-coroutine-sleep.c
-+++ b/util/qemu-coroutine-sleep.c
-@@ -XXX,XX +XXX,XX @@ static void co_sleep_cb(void *opaque)
- {
-     CoSleepCB *sleep_cb = opaque;
--    qemu_coroutine_enter(sleep_cb->co);
-+    aio_co_wake(sleep_cb->co);
- }
- void coroutine_fn co_aio_sleep_ns(AioContext *ctx, QEMUClockType type,
---
-.9.3

-[Qemu-devel] [PULL v2 18/24] block: document fields protected by AioContext lock
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
-Message-id: 20170213135235.12274-19-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- include/block/block_int.h      | 64 +++++++++++++++++++++++++-----------------
- include/sysemu/block-backend.h | 14 ++++++---
-files changed, 49 insertions(+), 29 deletions(-)
-diff --git a/include/block/block_int.h b/include/block/block_int.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/block/block_int.h
-+++ b/include/block/block_int.h
-@@ -XXX,XX +XXX,XX @@ struct BdrvChild {
-  * copied as well.
-  */
- struct BlockDriverState {
--    int64_t total_sectors; /* if we are reading a disk image, give its
--                              size in sectors */
-+    /* Protected by big QEMU lock or read-only after opening.  No special
-+     * locking needed during I/O...
-+     */
-     int open_flags; /* flags used to open the file, re-used for re-open */
-     bool read_only; /* if true, the media is read only */
-     bool encrypted; /* if true, the media is encrypted */
-@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
-     bool sg;        /* if true, the device is a /dev/sg* */
-     bool probed;    /* if true, format was probed rather than specified */
--    int copy_on_read; /* if nonzero, copy read backing sectors into image.
--                         note this is a reference count */
--
--    CoQueue flush_queue;            /* Serializing flush queue */
--    bool active_flush_req;          /* Flush request in flight? */
--    unsigned int write_gen;         /* Current data generation */
--    unsigned int flushed_gen;       /* Flushed write generation */
--
-     BlockDriver *drv; /* NULL means no media */
-     void *opaque;
-@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
-     BdrvChild *backing;
-     BdrvChild *file;
--    /* Callback before write request is processed */
--    NotifierWithReturnList before_write_notifiers;
--
--    /* number of in-flight requests; overall and serialising */
--    unsigned int in_flight;
--    unsigned int serialising_in_flight;
--
--    bool wakeup;
--
--    /* Offset after the highest byte written to */
--    uint64_t wr_highest_offset;
--
-     /* I/O Limits */
-     BlockLimits bl;
-@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
-     QTAILQ_ENTRY(BlockDriverState) bs_list;
-     /* element of the list of monitor-owned BDS */
-     QTAILQ_ENTRY(BlockDriverState) monitor_list;
--    QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
-     int refcnt;
--    QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
--
-     /* operation blockers */
-     QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX];
-@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
-     /* The error object in use for blocking operations on backing_hd */
-     Error *backing_blocker;
-+    /* Protected by AioContext lock */
-+
-+    /* If true, copy read backing sectors into image.  Can be >1 if more
-+     * than one client has requested copy-on-read.
-+     */
-+    int copy_on_read;
-+
-+    /* If we are reading a disk image, give its size in sectors.
-+     * Generally read-only; it is written to by load_vmstate and save_vmstate,
-+     * but the block layer is quiescent during those.
-+     */
-+    int64_t total_sectors;
-+
-+    /* Callback before write request is processed */
-+    NotifierWithReturnList before_write_notifiers;
-+
-+    /* number of in-flight requests; overall and serialising */
-+    unsigned int in_flight;
-+    unsigned int serialising_in_flight;
-+
-+    bool wakeup;
-+
-+    /* Offset after the highest byte written to */
-+    uint64_t wr_highest_offset;
-+
-     /* threshold limit for writes, in bytes. "High water mark". */
-     uint64_t write_threshold_offset;
-     NotifierWithReturn write_threshold_notifier;
-@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
-     /* counter for nested bdrv_io_plug */
-     unsigned io_plugged;
-+    QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
-+    CoQueue flush_queue;                  /* Serializing flush queue */
-+    bool active_flush_req;                /* Flush request in flight? */
-+    unsigned int write_gen;               /* Current data generation */
-+    unsigned int flushed_gen;             /* Flushed write generation */
-+
-+    QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
-+
-+    /* do we need to tell the quest if we have a volatile write cache? */
-+    int enable_write_cache;
-+
-     int quiesce_counter;
- };
-diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/sysemu/block-backend.h
-+++ b/include/sysemu/block-backend.h
-@@ -XXX,XX +XXX,XX @@ typedef struct BlockDevOps {
-  * fields that must be public. This is in particular for QLIST_ENTRY() and
-  * friends so that BlockBackends can be kept in lists outside block-backend.c */
- typedef struct BlockBackendPublic {
--    /* I/O throttling.
--     * throttle_state tells us if this BlockBackend has I/O limits configured.
--     * io_limits_disabled tells us if they are currently being enforced */
-+    /* I/O throttling has its own locking, but also some fields are
-+     * protected by the AioContext lock.
-+     */
-+
-+    /* Protected by AioContext lock.  */
-     CoQueue      throttled_reqs[2];
-+
-+    /* Nonzero if the I/O limits are currently being ignored; generally
-+     * it is zero.  */
-     unsigned int io_limits_disabled;
-     /* The following fields are protected by the ThrottleGroup lock.
--     * See the ThrottleGroup documentation for details. */
-+     * See the ThrottleGroup documentation for details.
-+     * throttle_state tells us if I/O limits are configured. */
-     ThrottleState *throttle_state;
-     ThrottleTimers throttle_timers;
-     unsigned       pending_reqs[2];
---
-.9.3

-[Qemu-devel] [PULL v2 19/24] coroutine-lock: make CoMutex thread-safe
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-This uses the lock-free mutex described in the paper '"Blocking without
-Locking", or LFTHREADS: A lock-free thread library' by Gidenstam and
-Papatriantafilou.  The same technique is used in OSv, and in fact
-the code is essentially a conversion to C of OSv's code.
-[Added missing coroutine_fn in tests/test-aio-multithread.c.
---Stefan]
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213181244.16297-2-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- include/qemu/coroutine.h     |  17 ++++-
- tests/test-aio-multithread.c |  86 ++++++++++++++++++++++++
- util/qemu-coroutine-lock.c   | 155 ++++++++++++++++++++++++++++++++++++++++---
- util/trace-events            |   1 +
-files changed, 246 insertions(+), 13 deletions(-)
-diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/qemu/coroutine.h
-+++ b/include/qemu/coroutine.h
-@@ -XXX,XX +XXX,XX @@ bool qemu_co_queue_empty(CoQueue *queue);
- /**
-  * Provides a mutex that can be used to synchronise coroutines
-  */
-+struct CoWaitRecord;
- typedef struct CoMutex {
--    bool locked;
-+    /* Count of pending lockers; 0 for a free mutex, 1 for an
-+     * uncontended mutex.
-+     */
-+    unsigned locked;
-+
-+    /* A queue of waiters.  Elements are added atomically in front of
-+     * from_push.  to_pop is only populated, and popped from, by whoever
-+     * is in charge of the next wakeup.  This can be an unlocker or,
-+     * through the handoff protocol, a locker that is about to go to sleep.
-+     */
-+    QSLIST_HEAD(, CoWaitRecord) from_push, to_pop;
-+
-+    unsigned handoff, sequence;
-+
-     Coroutine *holder;
--    CoQueue queue;
- } CoMutex;
- /**
-diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c
-index XXXXXXX..XXXXXXX 100644
---- a/tests/test-aio-multithread.c
-+++ b/tests/test-aio-multithread.c
-@@ -XXX,XX +XXX,XX @@ static void test_multi_co_schedule_10(void)
-     test_multi_co_schedule(10);
- }
-+/* CoMutex thread-safety.  */
-+
-+static uint32_t atomic_counter;
-+static uint32_t running;
-+static uint32_t counter;
-+static CoMutex comutex;
-+
-+static void coroutine_fn test_multi_co_mutex_entry(void *opaque)
-+{
-+    while (!atomic_mb_read(&now_stopping)) {
-+        qemu_co_mutex_lock(&comutex);
-+        counter++;
-+        qemu_co_mutex_unlock(&comutex);
-+
-+        /* Increase atomic_counter *after* releasing the mutex.  Otherwise
-+         * there is a chance (it happens about 1 in 3 runs) that the iothread
-+         * exits before the coroutine is woken up, causing a spurious
-+         * assertion failure.
-+         */
-+        atomic_inc(&atomic_counter);
-+    }
-+    atomic_dec(&running);
-+}
-+
-+static void test_multi_co_mutex(int threads, int seconds)
-+{
-+    int i;
-+
-+    qemu_co_mutex_init(&comutex);
-+    counter = 0;
-+    atomic_counter = 0;
-+    now_stopping = false;
-+
-+    create_aio_contexts();
-+    assert(threads <= NUM_CONTEXTS);
-+    running = threads;
-+    for (i = 0; i < threads; i++) {
-+        Coroutine *co1 = qemu_coroutine_create(test_multi_co_mutex_entry, NULL);
-+        aio_co_schedule(ctx[i], co1);
-+    }
-+
-+    g_usleep(seconds * 1000000);
-+
-+    atomic_mb_set(&now_stopping, true);
-+    while (running > 0) {
-+        g_usleep(100000);
-+    }
-+
-+    join_aio_contexts();
-+    g_test_message("%d iterations/second\n", counter / seconds);
-+    g_assert_cmpint(counter, ==, atomic_counter);
-+}
-+
-+/* Testing with NUM_CONTEXTS threads focuses on the queue.  The mutex however
-+ * is too contended (and the threads spend too much time in aio_poll)
-+ * to actually stress the handoff protocol.
-+ */
-+static void test_multi_co_mutex_1(void)
-+{
-+    test_multi_co_mutex(NUM_CONTEXTS, 1);
-+}
-+
-+static void test_multi_co_mutex_10(void)
-+{
-+    test_multi_co_mutex(NUM_CONTEXTS, 10);
-+}
-+
-+/* Testing with fewer threads stresses the handoff protocol too.  Still, the
-+ * case where the locker _can_ pick up a handoff is very rare, happening
-+ * about 10 times in 1 million, so increase the runtime a bit compared to
-+ * other "quick" testcases that only run for 1 second.
-+ */
-+static void test_multi_co_mutex_2_3(void)
-+{
-+    test_multi_co_mutex(2, 3);
-+}
-+
-+static void test_multi_co_mutex_2_30(void)
-+{
-+    test_multi_co_mutex(2, 30);
-+}
-+
- /* End of tests.  */
- int main(int argc, char **argv)
-@@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv)
-     g_test_add_func("/aio/multi/lifecycle", test_lifecycle);
-     if (g_test_quick()) {
-         g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_1);
-+        g_test_add_func("/aio/multi/mutex/contended", test_multi_co_mutex_1);
-+        g_test_add_func("/aio/multi/mutex/handoff", test_multi_co_mutex_2_3);
-     } else {
-         g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_10);
-+        g_test_add_func("/aio/multi/mutex/contended", test_multi_co_mutex_10);
-+        g_test_add_func("/aio/multi/mutex/handoff", test_multi_co_mutex_2_30);
-     }
-     return g_test_run();
- }
-diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/qemu-coroutine-lock.c
-+++ b/util/qemu-coroutine-lock.c
-@@ -XXX,XX +XXX,XX @@
-  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-  * THE SOFTWARE.
-+ *
-+ * The lock-free mutex implementation is based on OSv
-+ * (core/lfmutex.cc, include/lockfree/mutex.hh).
-+ * Copyright (C) 2013 Cloudius Systems, Ltd.
-  */
- #include "qemu/osdep.h"
-@@ -XXX,XX +XXX,XX @@ bool qemu_co_queue_empty(CoQueue *queue)
-     return QSIMPLEQ_FIRST(&queue->entries) == NULL;
- }
-+/* The wait records are handled with a multiple-producer, single-consumer
-+ * lock-free queue.  There cannot be two concurrent pop_waiter() calls
-+ * because pop_waiter() can only be called while mutex->handoff is zero.
-+ * This can happen in three cases:
-+ * - in qemu_co_mutex_unlock, before the hand-off protocol has started.
-+ *   In this case, qemu_co_mutex_lock will see mutex->handoff == 0 and
-+ *   not take part in the handoff.
-+ * - in qemu_co_mutex_lock, if it steals the hand-off responsibility from
-+ *   qemu_co_mutex_unlock.  In this case, qemu_co_mutex_unlock will fail
-+ *   the cmpxchg (it will see either 0 or the next sequence value) and
-+ *   exit.  The next hand-off cannot begin until qemu_co_mutex_lock has
-+ *   woken up someone.
-+ * - in qemu_co_mutex_unlock, if it takes the hand-off token itself.
-+ *   In this case another iteration starts with mutex->handoff == 0;
-+ *   a concurrent qemu_co_mutex_lock will fail the cmpxchg, and
-+ *   qemu_co_mutex_unlock will go back to case (1).
-+ *
-+ * The following functions manage this queue.
-+ */
-+typedef struct CoWaitRecord {
-+    Coroutine *co;
-+    QSLIST_ENTRY(CoWaitRecord) next;
-+} CoWaitRecord;
-+
-+static void push_waiter(CoMutex *mutex, CoWaitRecord *w)
-+{
-+    w->co = qemu_coroutine_self();
-+    QSLIST_INSERT_HEAD_ATOMIC(&mutex->from_push, w, next);
-+}
-+
-+static void move_waiters(CoMutex *mutex)
-+{
-+    QSLIST_HEAD(, CoWaitRecord) reversed;
-+    QSLIST_MOVE_ATOMIC(&reversed, &mutex->from_push);
-+    while (!QSLIST_EMPTY(&reversed)) {
-+        CoWaitRecord *w = QSLIST_FIRST(&reversed);
-+        QSLIST_REMOVE_HEAD(&reversed, next);
-+        QSLIST_INSERT_HEAD(&mutex->to_pop, w, next);
-+    }
-+}
-+
-+static CoWaitRecord *pop_waiter(CoMutex *mutex)
-+{
-+    CoWaitRecord *w;
-+
-+    if (QSLIST_EMPTY(&mutex->to_pop)) {
-+        move_waiters(mutex);
-+        if (QSLIST_EMPTY(&mutex->to_pop)) {
-+            return NULL;
-+        }
-+    }
-+    w = QSLIST_FIRST(&mutex->to_pop);
-+    QSLIST_REMOVE_HEAD(&mutex->to_pop, next);
-+    return w;
-+}
-+
-+static bool has_waiters(CoMutex *mutex)
-+{
-+    return QSLIST_EMPTY(&mutex->to_pop) || QSLIST_EMPTY(&mutex->from_push);
-+}
-+
- void qemu_co_mutex_init(CoMutex *mutex)
- {
-     memset(mutex, 0, sizeof(*mutex));
--    qemu_co_queue_init(&mutex->queue);
- }
--void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
-+static void coroutine_fn qemu_co_mutex_lock_slowpath(CoMutex *mutex)
- {
-     Coroutine *self = qemu_coroutine_self();
-+    CoWaitRecord w;
-+    unsigned old_handoff;
-     trace_qemu_co_mutex_lock_entry(mutex, self);
-+    w.co = self;
-+    push_waiter(mutex, &w);
--    while (mutex->locked) {
--        qemu_co_queue_wait(&mutex->queue);
-+    /* This is the "Responsibility Hand-Off" protocol; a lock() picks from
-+     * a concurrent unlock() the responsibility of waking somebody up.
-+     */
-+    old_handoff = atomic_mb_read(&mutex->handoff);
-+    if (old_handoff &&
-+        has_waiters(mutex) &&
-+        atomic_cmpxchg(&mutex->handoff, old_handoff, 0) == old_handoff) {
-+        /* There can be no concurrent pops, because there can be only
-+         * one active handoff at a time.
-+         */
-+        CoWaitRecord *to_wake = pop_waiter(mutex);
-+        Coroutine *co = to_wake->co;
-+        if (co == self) {
-+            /* We got the lock ourselves!  */
-+            assert(to_wake == &w);
-+            return;
-+        }
-+
-+        aio_co_wake(co);
-     }
--    mutex->locked = true;
--    mutex->holder = self;
--    self->locks_held++;
--
-+    qemu_coroutine_yield();
-     trace_qemu_co_mutex_lock_return(mutex, self);
- }
-+void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
-+{
-+    Coroutine *self = qemu_coroutine_self();
-+
-+    if (atomic_fetch_inc(&mutex->locked) == 0) {
-+        /* Uncontended.  */
-+        trace_qemu_co_mutex_lock_uncontended(mutex, self);
-+    } else {
-+        qemu_co_mutex_lock_slowpath(mutex);
-+    }
-+    mutex->holder = self;
-+    self->locks_held++;
-+}
-+
- void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
- {
-     Coroutine *self = qemu_coroutine_self();
-     trace_qemu_co_mutex_unlock_entry(mutex, self);
--    assert(mutex->locked == true);
-+    assert(mutex->locked);
-     assert(mutex->holder == self);
-     assert(qemu_in_coroutine());
--    mutex->locked = false;
-     mutex->holder = NULL;
-     self->locks_held--;
--    qemu_co_queue_next(&mutex->queue);
-+    if (atomic_fetch_dec(&mutex->locked) == 1) {
-+        /* No waiting qemu_co_mutex_lock().  Pfew, that was easy!  */
-+        return;
-+    }
-+
-+    for (;;) {
-+        CoWaitRecord *to_wake = pop_waiter(mutex);
-+        unsigned our_handoff;
-+
-+        if (to_wake) {
-+            Coroutine *co = to_wake->co;
-+            aio_co_wake(co);
-+            break;
-+        }
-+
-+        /* Some concurrent lock() is in progress (we know this because
-+         * mutex->locked was >1) but it hasn't yet put itself on the wait
-+         * queue.  Pick a sequence number for the handoff protocol (not 0).
-+         */
-+        if (++mutex->sequence == 0) {
-+            mutex->sequence = 1;
-+        }
-+
-+        our_handoff = mutex->sequence;
-+        atomic_mb_set(&mutex->handoff, our_handoff);
-+        if (!has_waiters(mutex)) {
-+            /* The concurrent lock has not added itself yet, so it
-+             * will be able to pick our handoff.
-+             */
-+            break;
-+        }
-+
-+        /* Try to do the handoff protocol ourselves; if somebody else has
-+         * already taken it, however, we're done and they're responsible.
-+         */
-+        if (atomic_cmpxchg(&mutex->handoff, our_handoff, 0) != our_handoff) {
-+            break;
-+        }
-+    }
-     trace_qemu_co_mutex_unlock_return(mutex, self);
- }
-diff --git a/util/trace-events b/util/trace-events
-index XXXXXXX..XXXXXXX 100644
---- a/util/trace-events
-+++ b/util/trace-events
-@@ -XXX,XX +XXX,XX @@ qemu_coroutine_terminate(void *co) "self %p"
- # util/qemu-coroutine-lock.c
- qemu_co_queue_run_restart(void *co) "co %p"
-+qemu_co_mutex_lock_uncontended(void *mutex, void *self) "mutex %p self %p"
- qemu_co_mutex_lock_entry(void *mutex, void *self) "mutex %p self %p"
- qemu_co_mutex_lock_return(void *mutex, void *self) "mutex %p self %p"
- qemu_co_mutex_unlock_entry(void *mutex, void *self) "mutex %p self %p"
---
-.9.3

-[Qemu-devel] [PULL v2 20/24] coroutine-lock: add limited spinning to CoMutex
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-Running a very small critical section on pthread_mutex_t and CoMutex
-shows that pthread_mutex_t is much faster because it doesn't actually
-go to sleep.  What happens is that the critical section is shorter
-than the latency of entering the kernel and thus FUTEX_WAIT always
-fails.  With CoMutex there is no such latency but you still want to
-avoid wait and wakeup.  So introduce it artificially.
-This only works with one waiters; because CoMutex is fair, it will
-always have more waits and wakeups than a pthread_mutex_t.
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213181244.16297-3-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- include/qemu/coroutine.h   |  5 +++++
- util/qemu-coroutine-lock.c | 51 ++++++++++++++++++++++++++++++++++++++++------
- util/qemu-coroutine.c      |  2 +-
-files changed, 51 insertions(+), 7 deletions(-)
-diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/qemu/coroutine.h
-+++ b/include/qemu/coroutine.h
-@@ -XXX,XX +XXX,XX @@ typedef struct CoMutex {
-      */
-     unsigned locked;
-+    /* Context that is holding the lock.  Useful to avoid spinning
-+     * when two coroutines on the same AioContext try to get the lock. :)
-+     */
-+    AioContext *ctx;
-+
-     /* A queue of waiters.  Elements are added atomically in front of
-      * from_push.  to_pop is only populated, and popped from, by whoever
-      * is in charge of the next wakeup.  This can be an unlocker or,
-diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/qemu-coroutine-lock.c
-+++ b/util/qemu-coroutine-lock.c
-@@ -XXX,XX +XXX,XX @@
- #include "qemu-common.h"
- #include "qemu/coroutine.h"
- #include "qemu/coroutine_int.h"
-+#include "qemu/processor.h"
- #include "qemu/queue.h"
- #include "block/aio.h"
- #include "trace.h"
-@@ -XXX,XX +XXX,XX @@ void qemu_co_mutex_init(CoMutex *mutex)
-     memset(mutex, 0, sizeof(*mutex));
- }
--static void coroutine_fn qemu_co_mutex_lock_slowpath(CoMutex *mutex)
-+static void coroutine_fn qemu_co_mutex_wake(CoMutex *mutex, Coroutine *co)
-+{
-+    /* Read co before co->ctx; pairs with smp_wmb() in
-+     * qemu_coroutine_enter().
-+     */
-+    smp_read_barrier_depends();
-+    mutex->ctx = co->ctx;
-+    aio_co_wake(co);
-+}
-+
-+static void coroutine_fn qemu_co_mutex_lock_slowpath(AioContext *ctx,
-+                                                     CoMutex *mutex)
- {
-     Coroutine *self = qemu_coroutine_self();
-     CoWaitRecord w;
-@@ -XXX,XX +XXX,XX @@ static void coroutine_fn qemu_co_mutex_lock_slowpath(CoMutex *mutex)
-         if (co == self) {
-             /* We got the lock ourselves!  */
-             assert(to_wake == &w);
-+            mutex->ctx = ctx;
-             return;
-         }
--        aio_co_wake(co);
-+        qemu_co_mutex_wake(mutex, co);
-     }
-     qemu_coroutine_yield();
-@@ -XXX,XX +XXX,XX @@ static void coroutine_fn qemu_co_mutex_lock_slowpath(CoMutex *mutex)
- void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
- {
-+    AioContext *ctx = qemu_get_current_aio_context();
-     Coroutine *self = qemu_coroutine_self();
-+    int waiters, i;
--    if (atomic_fetch_inc(&mutex->locked) == 0) {
-+    /* Running a very small critical section on pthread_mutex_t and CoMutex
-+     * shows that pthread_mutex_t is much faster because it doesn't actually
-+     * go to sleep.  What happens is that the critical section is shorter
-+     * than the latency of entering the kernel and thus FUTEX_WAIT always
-+     * fails.  With CoMutex there is no such latency but you still want to
-+     * avoid wait and wakeup.  So introduce it artificially.
-+     */
-+    i = 0;
-+retry_fast_path:
-+    waiters = atomic_cmpxchg(&mutex->locked, 0, 1);
-+    if (waiters != 0) {
-+        while (waiters == 1 && ++i < 1000) {
-+            if (atomic_read(&mutex->ctx) == ctx) {
-+                break;
-+            }
-+            if (atomic_read(&mutex->locked) == 0) {
-+                goto retry_fast_path;
-+            }
-+            cpu_relax();
-+        }
-+        waiters = atomic_fetch_inc(&mutex->locked);
-+    }
-+
-+    if (waiters == 0) {
-         /* Uncontended.  */
-         trace_qemu_co_mutex_lock_uncontended(mutex, self);
-+        mutex->ctx = ctx;
-     } else {
--        qemu_co_mutex_lock_slowpath(mutex);
-+        qemu_co_mutex_lock_slowpath(ctx, mutex);
-     }
-     mutex->holder = self;
-     self->locks_held++;
-@@ -XXX,XX +XXX,XX @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
-     assert(mutex->holder == self);
-     assert(qemu_in_coroutine());
-+    mutex->ctx = NULL;
-     mutex->holder = NULL;
-     self->locks_held--;
-     if (atomic_fetch_dec(&mutex->locked) == 1) {
-@@ -XXX,XX +XXX,XX @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
-         unsigned our_handoff;
-         if (to_wake) {
--            Coroutine *co = to_wake->co;
--            aio_co_wake(co);
-+            qemu_co_mutex_wake(mutex, to_wake->co);
-             break;
-         }
-diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/qemu-coroutine.c
-+++ b/util/qemu-coroutine.c
-@@ -XXX,XX +XXX,XX @@ void qemu_coroutine_enter(Coroutine *co)
-     co->ctx = qemu_get_current_aio_context();
-     /* Store co->ctx before anything that stores co.  Matches
--     * barrier in aio_co_wake.
-+     * barrier in aio_co_wake and qemu_co_mutex_wake.
-      */
-     smp_wmb();
---
-.9.3

-[Qemu-devel] [PULL v2 21/24] test-aio-multithread: add performance comparison with thread-based mutexes
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-Add two implementations of the same benchmark as the previous patch,
-but using pthreads.  One uses a normal QemuMutex, the other is Linux
-only and implements a fair mutex based on MCS locks and futexes.
-This shows that the slower performance of the 5-thread case is due to
-the fairness of CoMutex, rather than to coroutines.  If fairness does
-not matter, as is the case with two threads, CoMutex can actually be
-faster than pthreads.
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213181244.16297-4-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- tests/test-aio-multithread.c | 164 +++++++++++++++++++++++++++++++++++++++++++
-file changed, 164 insertions(+)
-diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c
-index XXXXXXX..XXXXXXX 100644
---- a/tests/test-aio-multithread.c
-+++ b/tests/test-aio-multithread.c
-@@ -XXX,XX +XXX,XX @@ static void test_multi_co_mutex_2_30(void)
-     test_multi_co_mutex(2, 30);
- }
-+/* Same test with fair mutexes, for performance comparison.  */
-+
-+#ifdef CONFIG_LINUX
-+#include "qemu/futex.h"
-+
-+/* The nodes for the mutex reside in this structure (on which we try to avoid
-+ * false sharing).  The head of the mutex is in the "mutex_head" variable.
-+ */
-+static struct {
-+    int next, locked;
-+    int padding[14];
-+} nodes[NUM_CONTEXTS] __attribute__((__aligned__(64)));
-+
-+static int mutex_head = -1;
-+
-+static void mcs_mutex_lock(void)
-+{
-+    int prev;
-+
-+    nodes[id].next = -1;
-+    nodes[id].locked = 1;
-+    prev = atomic_xchg(&mutex_head, id);
-+    if (prev != -1) {
-+        atomic_set(&nodes[prev].next, id);
-+        qemu_futex_wait(&nodes[id].locked, 1);
-+    }
-+}
-+
-+static void mcs_mutex_unlock(void)
-+{
-+    int next;
-+    if (nodes[id].next == -1) {
-+        if (atomic_read(&mutex_head) == id &&
-+            atomic_cmpxchg(&mutex_head, id, -1) == id) {
-+            /* Last item in the list, exit.  */
-+            return;
-+        }
-+        while (atomic_read(&nodes[id].next) == -1) {
-+            /* mcs_mutex_lock did the xchg, but has not updated
-+             * nodes[prev].next yet.
-+             */
-+        }
-+    }
-+
-+    /* Wake up the next in line.  */
-+    next = nodes[id].next;
-+    nodes[next].locked = 0;
-+    qemu_futex_wake(&nodes[next].locked, 1);
-+}
-+
-+static void test_multi_fair_mutex_entry(void *opaque)
-+{
-+    while (!atomic_mb_read(&now_stopping)) {
-+        mcs_mutex_lock();
-+        counter++;
-+        mcs_mutex_unlock();
-+        atomic_inc(&atomic_counter);
-+    }
-+    atomic_dec(&running);
-+}
-+
-+static void test_multi_fair_mutex(int threads, int seconds)
-+{
-+    int i;
-+
-+    assert(mutex_head == -1);
-+    counter = 0;
-+    atomic_counter = 0;
-+    now_stopping = false;
-+
-+    create_aio_contexts();
-+    assert(threads <= NUM_CONTEXTS);
-+    running = threads;
-+    for (i = 0; i < threads; i++) {
-+        Coroutine *co1 = qemu_coroutine_create(test_multi_fair_mutex_entry, NULL);
-+        aio_co_schedule(ctx[i], co1);
-+    }
-+
-+    g_usleep(seconds * 1000000);
-+
-+    atomic_mb_set(&now_stopping, true);
-+    while (running > 0) {
-+        g_usleep(100000);
-+    }
-+
-+    join_aio_contexts();
-+    g_test_message("%d iterations/second\n", counter / seconds);
-+    g_assert_cmpint(counter, ==, atomic_counter);
-+}
-+
-+static void test_multi_fair_mutex_1(void)
-+{
-+    test_multi_fair_mutex(NUM_CONTEXTS, 1);
-+}
-+
-+static void test_multi_fair_mutex_10(void)
-+{
-+    test_multi_fair_mutex(NUM_CONTEXTS, 10);
-+}
-+#endif
-+
-+/* Same test with pthread mutexes, for performance comparison and
-+ * portability.  */
-+
-+static QemuMutex mutex;
-+
-+static void test_multi_mutex_entry(void *opaque)
-+{
-+    while (!atomic_mb_read(&now_stopping)) {
-+        qemu_mutex_lock(&mutex);
-+        counter++;
-+        qemu_mutex_unlock(&mutex);
-+        atomic_inc(&atomic_counter);
-+    }
-+    atomic_dec(&running);
-+}
-+
-+static void test_multi_mutex(int threads, int seconds)
-+{
-+    int i;
-+
-+    qemu_mutex_init(&mutex);
-+    counter = 0;
-+    atomic_counter = 0;
-+    now_stopping = false;
-+
-+    create_aio_contexts();
-+    assert(threads <= NUM_CONTEXTS);
-+    running = threads;
-+    for (i = 0; i < threads; i++) {
-+        Coroutine *co1 = qemu_coroutine_create(test_multi_mutex_entry, NULL);
-+        aio_co_schedule(ctx[i], co1);
-+    }
-+
-+    g_usleep(seconds * 1000000);
-+
-+    atomic_mb_set(&now_stopping, true);
-+    while (running > 0) {
-+        g_usleep(100000);
-+    }
-+
-+    join_aio_contexts();
-+    g_test_message("%d iterations/second\n", counter / seconds);
-+    g_assert_cmpint(counter, ==, atomic_counter);
-+}
-+
-+static void test_multi_mutex_1(void)
-+{
-+    test_multi_mutex(NUM_CONTEXTS, 1);
-+}
-+
-+static void test_multi_mutex_10(void)
-+{
-+    test_multi_mutex(NUM_CONTEXTS, 10);
-+}
-+
- /* End of tests.  */
- int main(int argc, char **argv)
-@@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv)
-         g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_1);
-         g_test_add_func("/aio/multi/mutex/contended", test_multi_co_mutex_1);
-         g_test_add_func("/aio/multi/mutex/handoff", test_multi_co_mutex_2_3);
-+#ifdef CONFIG_LINUX
-+        g_test_add_func("/aio/multi/mutex/mcs", test_multi_fair_mutex_1);
-+#endif
-+        g_test_add_func("/aio/multi/mutex/pthread", test_multi_mutex_1);
-     } else {
-         g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_10);
-         g_test_add_func("/aio/multi/mutex/contended", test_multi_co_mutex_10);
-         g_test_add_func("/aio/multi/mutex/handoff", test_multi_co_mutex_2_30);
-+#ifdef CONFIG_LINUX
-+        g_test_add_func("/aio/multi/mutex/mcs", test_multi_fair_mutex_10);
-+#endif
-+        g_test_add_func("/aio/multi/mutex/pthread", test_multi_mutex_10);
-     }
-     return g_test_run();
- }
---
-.9.3

-[Qemu-devel] [PULL v2 22/24] coroutine-lock: place CoMutex before CoQueue in header
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-This will avoid forward references in the next patch.  It is also
-more logical because CoQueue is not anymore the basic primitive.
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213181244.16297-5-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- include/qemu/coroutine.h | 89 ++++++++++++++++++++++++------------------------
-file changed, 44 insertions(+), 45 deletions(-)
-diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/qemu/coroutine.h
-+++ b/include/qemu/coroutine.h
-@@ -XXX,XX +XXX,XX @@ bool qemu_in_coroutine(void);
-  */
- bool qemu_coroutine_entered(Coroutine *co);
--
--/**
-- * CoQueues are a mechanism to queue coroutines in order to continue executing
-- * them later. They provide the fundamental primitives on which coroutine locks
-- * are built.
-- */
--typedef struct CoQueue {
--    QSIMPLEQ_HEAD(, Coroutine) entries;
--} CoQueue;
--
--/**
-- * Initialise a CoQueue. This must be called before any other operation is used
-- * on the CoQueue.
-- */
--void qemu_co_queue_init(CoQueue *queue);
--
--/**
-- * Adds the current coroutine to the CoQueue and transfers control to the
-- * caller of the coroutine.
-- */
--void coroutine_fn qemu_co_queue_wait(CoQueue *queue);
--
--/**
-- * Restarts the next coroutine in the CoQueue and removes it from the queue.
-- *
-- * Returns true if a coroutine was restarted, false if the queue is empty.
-- */
--bool coroutine_fn qemu_co_queue_next(CoQueue *queue);
--
--/**
-- * Restarts all coroutines in the CoQueue and leaves the queue empty.
-- */
--void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue);
--
--/**
-- * Enter the next coroutine in the queue
-- */
--bool qemu_co_enter_next(CoQueue *queue);
--
--/**
-- * Checks if the CoQueue is empty.
-- */
--bool qemu_co_queue_empty(CoQueue *queue);
--
--
- /**
-  * Provides a mutex that can be used to synchronise coroutines
-  */
-@@ -XXX,XX +XXX,XX @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex);
-  */
- void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
-+
-+/**
-+ * CoQueues are a mechanism to queue coroutines in order to continue executing
-+ * them later.
-+ */
-+typedef struct CoQueue {
-+    QSIMPLEQ_HEAD(, Coroutine) entries;
-+} CoQueue;
-+
-+/**
-+ * Initialise a CoQueue. This must be called before any other operation is used
-+ * on the CoQueue.
-+ */
-+void qemu_co_queue_init(CoQueue *queue);
-+
-+/**
-+ * Adds the current coroutine to the CoQueue and transfers control to the
-+ * caller of the coroutine.
-+ */
-+void coroutine_fn qemu_co_queue_wait(CoQueue *queue);
-+
-+/**
-+ * Restarts the next coroutine in the CoQueue and removes it from the queue.
-+ *
-+ * Returns true if a coroutine was restarted, false if the queue is empty.
-+ */
-+bool coroutine_fn qemu_co_queue_next(CoQueue *queue);
-+
-+/**
-+ * Restarts all coroutines in the CoQueue and leaves the queue empty.
-+ */
-+void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue);
-+
-+/**
-+ * Enter the next coroutine in the queue
-+ */
-+bool qemu_co_enter_next(CoQueue *queue);
-+
-+/**
-+ * Checks if the CoQueue is empty.
-+ */
-+bool qemu_co_queue_empty(CoQueue *queue);
-+
-+
- typedef struct CoRwlock {
-     bool writer;
-     int reader;
---
-.9.3

-[Qemu-devel] [PULL v2 24/24] coroutine-lock: make CoRwlock thread-safe and fair
+Deleted patch
-From: Paolo Bonzini <pbonzini@redhat.com>
-This adds a CoMutex around the existing CoQueue.  Because the write-side
-can just take CoMutex, the old "writer" field is not necessary anymore.
-Instead of removing it altogether, count the number of pending writers
-during a read-side critical section and forbid further readers from
-entering.
-Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-Reviewed-by: Fam Zheng <famz@redhat.com>
-Message-id: 20170213181244.16297-7-pbonzini@redhat.com
-Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
----
- include/qemu/coroutine.h   |  3 ++-
- util/qemu-coroutine-lock.c | 35 ++++++++++++++++++++++++-----------
-files changed, 26 insertions(+), 12 deletions(-)
-diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
-index XXXXXXX..XXXXXXX 100644
---- a/include/qemu/coroutine.h
-+++ b/include/qemu/coroutine.h
-@@ -XXX,XX +XXX,XX @@ bool qemu_co_queue_empty(CoQueue *queue);
- typedef struct CoRwlock {
--    bool writer;
-+    int pending_writer;
-     int reader;
-+    CoMutex mutex;
-     CoQueue queue;
- } CoRwlock;
-diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
-index XXXXXXX..XXXXXXX 100644
---- a/util/qemu-coroutine-lock.c
-+++ b/util/qemu-coroutine-lock.c
-@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_init(CoRwlock *lock)
- {
-     memset(lock, 0, sizeof(*lock));
-     qemu_co_queue_init(&lock->queue);
-+    qemu_co_mutex_init(&lock->mutex);
- }
- void qemu_co_rwlock_rdlock(CoRwlock *lock)
- {
-     Coroutine *self = qemu_coroutine_self();
--    while (lock->writer) {
--        qemu_co_queue_wait(&lock->queue, NULL);
-+    qemu_co_mutex_lock(&lock->mutex);
-+    /* For fairness, wait if a writer is in line.  */
-+    while (lock->pending_writer) {
-+        qemu_co_queue_wait(&lock->queue, &lock->mutex);
-     }
-     lock->reader++;
-+    qemu_co_mutex_unlock(&lock->mutex);
-+
-+    /* The rest of the read-side critical section is run without the mutex.  */
-     self->locks_held++;
- }
-@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_unlock(CoRwlock *lock)
-     Coroutine *self = qemu_coroutine_self();
-     assert(qemu_in_coroutine());
--    if (lock->writer) {
--        lock->writer = false;
-+    if (!lock->reader) {
-+        /* The critical section started in qemu_co_rwlock_wrlock.  */
-         qemu_co_queue_restart_all(&lock->queue);
-     } else {
-+        self->locks_held--;
-+
-+        qemu_co_mutex_lock(&lock->mutex);
-         lock->reader--;
-         assert(lock->reader >= 0);
-         /* Wakeup only one waiting writer */
-@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_unlock(CoRwlock *lock)
-             qemu_co_queue_next(&lock->queue);
-         }
-     }
--    self->locks_held--;
-+    qemu_co_mutex_unlock(&lock->mutex);
- }
- void qemu_co_rwlock_wrlock(CoRwlock *lock)
- {
--    Coroutine *self = qemu_coroutine_self();
--
--    while (lock->writer || lock->reader) {
--        qemu_co_queue_wait(&lock->queue, NULL);
-+    qemu_co_mutex_lock(&lock->mutex);
-+    lock->pending_writer++;
-+    while (lock->reader) {
-+        qemu_co_queue_wait(&lock->queue, &lock->mutex);
-     }
--    lock->writer = true;
--    self->locks_held++;
-+    lock->pending_writer--;
-+
-+    /* The rest of the write-side critical section is run with
-+     * the mutex taken, so that lock->reader remains zero.
-+     * There is no need to update self->locks_held.
-+     */
- }
---
-.9.3

The following changes since commit 56f9e46b841c7be478ca038d8d4085d776ab4b0d:

Merge remote-tracking branch 'remotes/armbru/tags/pull-qapi-2017-02-20' into staging (2017-02-20 17:42:47 +0000)

are available in the git repository at:

git://github.com/stefanha/qemu.git tags/block-pull-request

for you to fetch changes up to a7b91d35bab97a2d3e779d0c64c9b837b52a6cf7:

coroutine-lock: make CoRwlock thread-safe and fair (2017-02-21 11:39:40 +0000)

----------------------------------------------------------------
Pull request

v2:
 * Rebased to resolve scsi conflicts

----------------------------------------------------------------

Paolo Bonzini (24):
  block: move AioContext, QEMUTimer, main-loop to libqemuutil
  aio: introduce aio_co_schedule and aio_co_wake
  block-backend: allow blk_prw from coroutine context
  test-thread-pool: use generic AioContext infrastructure
  io: add methods to set I/O handlers on AioContext
  io: make qio_channel_yield aware of AioContexts
  nbd: convert to use qio_channel_yield
  coroutine-lock: reschedule coroutine on the AioContext it was running
    on
  blkdebug: reschedule coroutine on the AioContext it is running on
  qed: introduce qed_aio_start_io and qed_aio_next_io_cb
  aio: push aio_context_acquire/release down to dispatching
  block: explicitly acquire aiocontext in timers that need it
  block: explicitly acquire aiocontext in callbacks that need it
  block: explicitly acquire aiocontext in bottom halves that need it
  block: explicitly acquire aiocontext in aio callbacks that need it
  aio-posix: partially inline aio_dispatch into aio_poll
  async: remove unnecessary inc/dec pairs
  block: document fields protected by AioContext lock
  coroutine-lock: make CoMutex thread-safe
  coroutine-lock: add limited spinning to CoMutex
  test-aio-multithread: add performance comparison with thread-based
    mutexes
  coroutine-lock: place CoMutex before CoQueue in header
  coroutine-lock: add mutex argument to CoQueue APIs
  coroutine-lock: make CoRwlock thread-safe and fair

-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

AioContext is fairly self contained, the only dependency is QEMUTimer but
that in turn doesn't need anything else.  So move them out of block-obj-y
to avoid introducing a dependency from io/ to block-obj-y.

main-loop and its dependency iohandler also need to be moved, because
later in this series io/ will call iohandler_get_aio_context.

[Changed copyright "the QEMU team" to "other QEMU contributors" as
suggested by Daniel Berrange and agreed by Paolo.
--Stefan]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213135235.12274-2-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 Makefile.objs                       |  4 ---
 stubs/Makefile.objs                 |  1 +
 tests/Makefile.include              | 11 ++++----
 util/Makefile.objs                  |  6 +++-
 block/io.c                          | 29 -------------------
 stubs/linux-aio.c                   | 32 +++++++++++++++++++++
 stubs/set-fd-handler.c              | 11 --------
 aio-posix.c => util/aio-posix.c     |  2 +-
 aio-win32.c => util/aio-win32.c     |  0
 util/aiocb.c                        | 55 +++++++++++++++++++++++++++++++++++++
 async.c => util/async.c             |  3 +-
 iohandler.c => util/iohandler.c     |  0
 main-loop.c => util/main-loop.c     |  0
 qemu-timer.c => util/qemu-timer.c   |  0
 thread-pool.c => util/thread-pool.c |  2 +-
 trace-events                        | 11 --------
 util/trace-events                   | 11 ++++++++
 17 files changed, 114 insertions(+), 64 deletions(-)
 create mode 100644 stubs/linux-aio.c
 rename aio-posix.c => util/aio-posix.c (99%)
 rename aio-win32.c => util/aio-win32.c (100%)
 create mode 100644 util/aiocb.c
 rename async.c => util/async.c (99%)
 rename iohandler.c => util/iohandler.c (100%)
 rename main-loop.c => util/main-loop.c (100%)
 rename qemu-timer.c => util/qemu-timer.c (100%)
 rename thread-pool.c => util/thread-pool.c (99%)

diff --git a/Makefile.objs b/Makefile.objs
index XXXXXXX..XXXXXXX 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -XXX,XX +XXX,XX @@ chardev-obj-y = chardev/
 #######################################################################
 # block-obj-y is code used by both qemu system emulation and qemu-img
 
-block-obj-y = async.o thread-pool.o
 block-obj-y += nbd/
 block-obj-y += block.o blockjob.o
-block-obj-y += main-loop.o iohandler.o qemu-timer.o
-block-obj-$(CONFIG_POSIX) += aio-posix.o
-block-obj-$(CONFIG_WIN32) += aio-win32.o
 block-obj-y += block/
 block-obj-y += qemu-io-cmds.o
 block-obj-$(CONFIG_REPLICATION) += replication.o
diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index XXXXXXX..XXXXXXX 100644
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -XXX,XX +XXX,XX @@ stub-obj-y += get-vm-name.o
 stub-obj-y += iothread.o
 stub-obj-y += iothread-lock.o
 stub-obj-y += is-daemonized.o
+stub-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
 stub-obj-y += machine-init-done.o
 stub-obj-y += migr-blocker.o
 stub-obj-y += monitor.o
diff --git a/tests/Makefile.include b/tests/Makefile.include
index XXXXXXX..XXXXXXX 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -XXX,XX +XXX,XX @@ check-unit-y += tests/test-visitor-serialization$(EXESUF)
 check-unit-y += tests/test-iov$(EXESUF)
 gcov-files-test-iov-y = util/iov.c
 check-unit-y += tests/test-aio$(EXESUF)
+gcov-files-test-aio-y = util/async.c util/qemu-timer.o
+gcov-files-test-aio-$(CONFIG_WIN32) += util/aio-win32.c
+gcov-files-test-aio-$(CONFIG_POSIX) += util/aio-posix.c
 check-unit-y += tests/test-throttle$(EXESUF)
 gcov-files-test-aio-$(CONFIG_WIN32) = aio-win32.c
 gcov-files-test-aio-$(CONFIG_POSIX) = aio-posix.c
@@ -XXX,XX +XXX,XX @@ tests/check-qjson$(EXESUF): tests/check-qjson.o $(test-util-obj-y)
 tests/check-qom-interface$(EXESUF): tests/check-qom-interface.o $(test-qom-obj-y)
 tests/check-qom-proplist$(EXESUF): tests/check-qom-proplist.o $(test-qom-obj-y)
 
-tests/test-char$(EXESUF): tests/test-char.o qemu-timer.o \
-	$(test-util-obj-y) $(qtest-obj-y) $(test-block-obj-y) $(chardev-obj-y)
+tests/test-char$(EXESUF): tests/test-char.o $(test-util-obj-y) $(qtest-obj-y) $(test-io-obj-y) $(chardev-obj-y)
 tests/test-coroutine$(EXESUF): tests/test-coroutine.o $(test-block-obj-y)
 tests/test-aio$(EXESUF): tests/test-aio.o $(test-block-obj-y)
 tests/test-throttle$(EXESUF): tests/test-throttle.o $(test-block-obj-y)
@@ -XXX,XX +XXX,XX @@ tests/test-vmstate$(EXESUF): tests/test-vmstate.o \
 	migration/vmstate.o migration/qemu-file.o \
         migration/qemu-file-channel.o migration/qjson.o \
 	$(test-io-obj-y)
-tests/test-timed-average$(EXESUF): tests/test-timed-average.o qemu-timer.o \
-	$(test-util-obj-y)
+tests/test-timed-average$(EXESUF): tests/test-timed-average.o $(test-util-obj-y)
 tests/test-base64$(EXESUF): tests/test-base64.o \
 	libqemuutil.a libqemustub.a
 tests/ptimer-test$(EXESUF): tests/ptimer-test.o tests/ptimer-test-stubs.o hw/core/ptimer.o libqemustub.a
@@ -XXX,XX +XXX,XX @@ tests/usb-hcd-ehci-test$(EXESUF): tests/usb-hcd-ehci-test.o $(libqos-usb-obj-y)
 tests/usb-hcd-xhci-test$(EXESUF): tests/usb-hcd-xhci-test.o $(libqos-usb-obj-y)
 tests/pc-cpu-test$(EXESUF): tests/pc-cpu-test.o
 tests/postcopy-test$(EXESUF): tests/postcopy-test.o
-tests/vhost-user-test$(EXESUF): tests/vhost-user-test.o qemu-timer.o \
+tests/vhost-user-test$(EXESUF): tests/vhost-user-test.o $(test-util-obj-y) \
 	$(qtest-obj-y) $(test-io-obj-y) $(libqos-virtio-obj-y) $(libqos-pc-obj-y) \
 	$(chardev-obj-y)
 tests/qemu-iotests/socket_scm_helper$(EXESUF): tests/qemu-iotests/socket_scm_helper.o
diff --git a/util/Makefile.objs b/util/Makefile.objs
index XXXXXXX..XXXXXXX 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -XXX,XX +XXX,XX @@
 util-obj-y = osdep.o cutils.o unicode.o qemu-timer-common.o
 util-obj-y += bufferiszero.o
 util-obj-y += lockcnt.o
+util-obj-y += aiocb.o async.o thread-pool.o qemu-timer.o
+util-obj-y += main-loop.o iohandler.o
+util-obj-$(CONFIG_POSIX) += aio-posix.o
 util-obj-$(CONFIG_POSIX) += compatfd.o
 util-obj-$(CONFIG_POSIX) += event_notifier-posix.o
 util-obj-$(CONFIG_POSIX) += mmap-alloc.o
 util-obj-$(CONFIG_POSIX) += oslib-posix.o
 util-obj-$(CONFIG_POSIX) += qemu-openpty.o
 util-obj-$(CONFIG_POSIX) += qemu-thread-posix.o
-util-obj-$(CONFIG_WIN32) += event_notifier-win32.o
 util-obj-$(CONFIG_POSIX) += memfd.o
+util-obj-$(CONFIG_WIN32) += aio-win32.o
+util-obj-$(CONFIG_WIN32) += event_notifier-win32.o
 util-obj-$(CONFIG_WIN32) += oslib-win32.o
 util-obj-$(CONFIG_WIN32) += qemu-thread-win32.o
 util-obj-y += envlist.o path.o module.o
diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ BlockAIOCB *bdrv_aio_flush(BlockDriverState *bs,
     return &acb->common;
 }
 
-void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
-                   BlockCompletionFunc *cb, void *opaque)
-{
-    BlockAIOCB *acb;
-
-    acb = g_malloc(aiocb_info->aiocb_size);
-    acb->aiocb_info = aiocb_info;
-    acb->bs = bs;
-    acb->cb = cb;
-    acb->opaque = opaque;
-    acb->refcnt = 1;
-    return acb;
-}
-
-void qemu_aio_ref(void *p)
-{
-    BlockAIOCB *acb = p;
-    acb->refcnt++;
-}
-
-void qemu_aio_unref(void *p)
-{
-    BlockAIOCB *acb = p;
-    assert(acb->refcnt > 0);
-    if (--acb->refcnt == 0) {
-        g_free(acb);
-    }
-}
-
 /**************************************************************/
 /* Coroutine block device emulation */
 
diff --git a/stubs/linux-aio.c b/stubs/linux-aio.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/stubs/linux-aio.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Linux native AIO support.
+ *
+ * Copyright (C) 2009 IBM, Corp.
+ * Copyright (C) 2009 Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#include "qemu/osdep.h"
+#include "block/aio.h"
+#include "block/raw-aio.h"
+
+void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context)
+{
+    abort();
+}
+
+void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context)
+{
+    abort();
+}
+
+LinuxAioState *laio_init(void)
+{
+    abort();
+}
+
+void laio_cleanup(LinuxAioState *s)
+{
+    abort();
+}
diff --git a/stubs/set-fd-handler.c b/stubs/set-fd-handler.c
index XXXXXXX..XXXXXXX 100644
--- a/stubs/set-fd-handler.c
+++ b/stubs/set-fd-handler.c
@@ -XXX,XX +XXX,XX @@ void qemu_set_fd_handler(int fd,
 {
     abort();
 }
-
-void aio_set_fd_handler(AioContext *ctx,
-                        int fd,
-                        bool is_external,
-                        IOHandler *io_read,
-                        IOHandler *io_write,
-                        AioPollFn *io_poll,
-                        void *opaque)
-{
-    abort();
-}
diff --git a/aio-posix.c b/util/aio-posix.c
similarity index 99%
rename from aio-posix.c
rename to util/aio-posix.c
index XXXXXXX..XXXXXXX 100644
--- a/aio-posix.c
+++ b/util/aio-posix.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/rcu_queue.h"
 #include "qemu/sockets.h"
 #include "qemu/cutils.h"
-#include "trace-root.h"
+#include "trace.h"
 #ifdef CONFIG_EPOLL_CREATE1
 #include <sys/epoll.h>
 #endif
diff --git a/aio-win32.c b/util/aio-win32.c
similarity index 100%
rename from aio-win32.c
rename to util/aio-win32.c
diff --git a/util/aiocb.c b/util/aiocb.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/util/aiocb.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * BlockAIOCB allocation
+ *
+ * Copyright (c) 2003-2017 Fabrice Bellard and other QEMU contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+#include "block/aio.h"
+
+void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
+                   BlockCompletionFunc *cb, void *opaque)
+{
+    BlockAIOCB *acb;
+
+    acb = g_malloc(aiocb_info->aiocb_size);
+    acb->aiocb_info = aiocb_info;
+    acb->bs = bs;
+    acb->cb = cb;
+    acb->opaque = opaque;
+    acb->refcnt = 1;
+    return acb;
+}
+
+void qemu_aio_ref(void *p)
+{
+    BlockAIOCB *acb = p;
+    acb->refcnt++;
+}
+
+void qemu_aio_unref(void *p)
+{
+    BlockAIOCB *acb = p;
+    assert(acb->refcnt > 0);
+    if (--acb->refcnt == 0) {
+        g_free(acb);
+    }
+}
diff --git a/async.c b/util/async.c
similarity index 99%
rename from async.c
rename to util/async.c
index XXXXXXX..XXXXXXX 100644
--- a/async.c
+++ b/util/async.c
@@ -XXX,XX +XXX,XX @@
 /*
- * QEMU System Emulator
+ * Data plane event loop
  *
  * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2009-2017 QEMU contributors
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
diff --git a/iohandler.c b/util/iohandler.c
similarity index 100%
rename from iohandler.c
rename to util/iohandler.c
diff --git a/main-loop.c b/util/main-loop.c
similarity index 100%
rename from main-loop.c
rename to util/main-loop.c
diff --git a/qemu-timer.c b/util/qemu-timer.c
similarity index 100%
rename from qemu-timer.c
rename to util/qemu-timer.c
diff --git a/thread-pool.c b/util/thread-pool.c
similarity index 99%
rename from thread-pool.c
rename to util/thread-pool.c
index XXXXXXX..XXXXXXX 100644
--- a/thread-pool.c
+++ b/util/thread-pool.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/queue.h"
 #include "qemu/thread.h"
 #include "qemu/coroutine.h"
-#include "trace-root.h"
+#include "trace.h"
 #include "block/thread-pool.h"
 #include "qemu/main-loop.h"
 
diff --git a/trace-events b/trace-events
index XXXXXXX..XXXXXXX 100644
--- a/trace-events
+++ b/trace-events
@@ -XXX,XX +XXX,XX @@
 #
 # The <format-string> should be a sprintf()-compatible format string.
 
-# aio-posix.c
-run_poll_handlers_begin(void *ctx, int64_t max_ns) "ctx %p max_ns %"PRId64
-run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d"
-poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
-poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
-
-# thread-pool.c
-thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p"
-thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d"
-thread_pool_cancel(void *req, void *opaque) "req %p opaque %p"
-
 # ioport.c
 cpu_in(unsigned int addr, char size, unsigned int val) "addr %#x(%c) value %u"
 cpu_out(unsigned int addr, char size, unsigned int val) "addr %#x(%c) value %u"
diff --git a/util/trace-events b/util/trace-events
index XXXXXXX..XXXXXXX 100644
--- a/util/trace-events
+++ b/util/trace-events
@@ -XXX,XX +XXX,XX @@
 # See docs/tracing.txt for syntax documentation.
 
+# util/aio-posix.c
+run_poll_handlers_begin(void *ctx, int64_t max_ns) "ctx %p max_ns %"PRId64
+run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d"
+poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
+poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
+
+# util/thread-pool.c
+thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p"
+thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d"
+thread_pool_cancel(void *req, void *opaque) "req %p opaque %p"
+
 # util/buffer.c
 buffer_resize(const char *buf, size_t olen, size_t len) "%s: old %zd, new %zd"
 buffer_move_empty(const char *buf, size_t len, const char *from) "%s: %zd bytes from %s"
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

aio_co_wake provides the infrastructure to start a coroutine on a "home"
AioContext.  It will be used by CoMutex and CoQueue, so that coroutines
don't jump from one context to another when they go to sleep on a
mutex or waitqueue.  However, it can also be used as a more efficient
alternative to one-shot bottom halves, and saves the effort of tracking
which AioContext a coroutine is running on.

aio_co_schedule is the part of aio_co_wake that starts a coroutine
on a remove AioContext, but it is also useful to implement e.g.
bdrv_set_aio_context callbacks.

The implementation of aio_co_schedule is based on a lock-free
multiple-producer, single-consumer queue.  The multiple producers use
cmpxchg to add to a LIFO stack.  The consumer (a per-AioContext bottom
half) grabs all items added so far, inverts the list to make it FIFO,
and goes through it one item at a time until it's empty.  The data
structure was inspired by OSv, which uses it in the very code we'll
"port" to QEMU for the thread-safe CoMutex.

Most of the new code is really tests.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213135235.12274-3-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/Makefile.include       |   8 +-
 include/block/aio.h          |  32 +++++++
 include/qemu/coroutine_int.h |  11 ++-
 tests/iothread.h             |  25 +++++
 tests/iothread.c             |  91 ++++++++++++++++++
 tests/test-aio-multithread.c | 213 +++++++++++++++++++++++++++++++++++++++++++
 util/async.c                 |  65 +++++++++++++
 util/qemu-coroutine.c        |   8 ++
 util/trace-events            |   4 +
 9 files changed, 453 insertions(+), 4 deletions(-)
 create mode 100644 tests/iothread.h
 create mode 100644 tests/iothread.c
 create mode 100644 tests/test-aio-multithread.c

diff --git a/tests/Makefile.include b/tests/Makefile.include
index XXXXXXX..XXXXXXX 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -XXX,XX +XXX,XX @@ check-unit-y += tests/test-aio$(EXESUF)
 gcov-files-test-aio-y = util/async.c util/qemu-timer.o
 gcov-files-test-aio-$(CONFIG_WIN32) += util/aio-win32.c
 gcov-files-test-aio-$(CONFIG_POSIX) += util/aio-posix.c
+check-unit-y += tests/test-aio-multithread$(EXESUF)
+gcov-files-test-aio-multithread-y = $(gcov-files-test-aio-y)
+gcov-files-test-aio-multithread-y += util/qemu-coroutine.c tests/iothread.c
 check-unit-y += tests/test-throttle$(EXESUF)
-gcov-files-test-aio-$(CONFIG_WIN32) = aio-win32.c
-gcov-files-test-aio-$(CONFIG_POSIX) = aio-posix.c
 check-unit-y += tests/test-thread-pool$(EXESUF)
 gcov-files-test-thread-pool-y = thread-pool.c
 gcov-files-test-hbitmap-y = util/hbitmap.c
@@ -XXX,XX +XXX,XX @@ test-qapi-obj-y = tests/test-qapi-visit.o tests/test-qapi-types.o \
 	$(test-qom-obj-y)
 test-crypto-obj-y = $(crypto-obj-y) $(test-qom-obj-y)
 test-io-obj-y = $(io-obj-y) $(test-crypto-obj-y)
-test-block-obj-y = $(block-obj-y) $(test-io-obj-y)
+test-block-obj-y = $(block-obj-y) $(test-io-obj-y) tests/iothread.o
 
 tests/check-qint$(EXESUF): tests/check-qint.o $(test-util-obj-y)
 tests/check-qstring$(EXESUF): tests/check-qstring.o $(test-util-obj-y)
@@ -XXX,XX +XXX,XX @@ tests/check-qom-proplist$(EXESUF): tests/check-qom-proplist.o $(test-qom-obj-y)
 tests/test-char$(EXESUF): tests/test-char.o $(test-util-obj-y) $(qtest-obj-y) $(test-io-obj-y) $(chardev-obj-y)
 tests/test-coroutine$(EXESUF): tests/test-coroutine.o $(test-block-obj-y)
 tests/test-aio$(EXESUF): tests/test-aio.o $(test-block-obj-y)
+tests/test-aio-multithread$(EXESUF): tests/test-aio-multithread.o $(test-block-obj-y)
 tests/test-throttle$(EXESUF): tests/test-throttle.o $(test-block-obj-y)
 tests/test-blockjob$(EXESUF): tests/test-blockjob.o $(test-block-obj-y) $(test-util-obj-y)
 tests/test-blockjob-txn$(EXESUF): tests/test-blockjob-txn.o $(test-block-obj-y) $(test-util-obj-y)
diff --git a/include/block/aio.h b/include/block/aio.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -XXX,XX +XXX,XX @@ typedef void QEMUBHFunc(void *opaque);
 typedef bool AioPollFn(void *opaque);
 typedef void IOHandler(void *opaque);
 
+struct Coroutine;
 struct ThreadPool;
 struct LinuxAioState;
 
@@ -XXX,XX +XXX,XX @@ struct AioContext {
     bool notified;
     EventNotifier notifier;
 
+    QSLIST_HEAD(, Coroutine) scheduled_coroutines;
+    QEMUBH *co_schedule_bh;
+
     /* Thread pool for performing work and receiving completion callbacks.
      * Has its own locking.
      */
@@ -XXX,XX +XXX,XX @@ static inline bool aio_node_check(AioContext *ctx, bool is_external)
 }
 
 /**
+ * aio_co_schedule:
+ * @ctx: the aio context
+ * @co: the coroutine
+ *
+ * Start a coroutine on a remote AioContext.
+ *
+ * The coroutine must not be entered by anyone else while aio_co_schedule()
+ * is active.  In addition the coroutine must have yielded unless ctx
+ * is the context in which the coroutine is running (i.e. the value of
+ * qemu_get_current_aio_context() from the coroutine itself).
+ */
+void aio_co_schedule(AioContext *ctx, struct Coroutine *co);
+
+/**
+ * aio_co_wake:
+ * @co: the coroutine
+ *
+ * Restart a coroutine on the AioContext where it was running last, thus
+ * preventing coroutines from jumping from one context to another when they
+ * go to sleep.
+ *
+ * aio_co_wake may be executed either in coroutine or non-coroutine
+ * context.  The coroutine must not be entered by anyone else while
+ * aio_co_wake() is active.
+ */
+void aio_co_wake(struct Coroutine *co);
+
+/**
  * Return the AioContext whose event loop runs in the current thread.
  *
  * If called from an IOThread this will be the IOThread's AioContext.  If
diff --git a/include/qemu/coroutine_int.h b/include/qemu/coroutine_int.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/coroutine_int.h
+++ b/include/qemu/coroutine_int.h
@@ -XXX,XX +XXX,XX @@ struct Coroutine {
     CoroutineEntry *entry;
     void *entry_arg;
     Coroutine *caller;
+
+    /* Only used when the coroutine has terminated.  */
     QSLIST_ENTRY(Coroutine) pool_next;
+
     size_t locks_held;
 
-    /* Coroutines that should be woken up when we yield or terminate */
+    /* Coroutines that should be woken up when we yield or terminate.
+     * Only used when the coroutine is running.
+     */
     QSIMPLEQ_HEAD(, Coroutine) co_queue_wakeup;
+
+    /* Only used when the coroutine has yielded.  */
+    AioContext *ctx;
     QSIMPLEQ_ENTRY(Coroutine) co_queue_next;
+    QSLIST_ENTRY(Coroutine) co_scheduled_next;
 };
 
 Coroutine *qemu_coroutine_new(void);
diff --git a/tests/iothread.h b/tests/iothread.h
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/tests/iothread.h
@@ -XXX,XX +XXX,XX @@
+/*
+ * Event loop thread implementation for unit tests
+ *
+ * Copyright Red Hat Inc., 2013, 2016
+ *
+ * Authors:
+ *  Stefan Hajnoczi   <stefanha@redhat.com>
+ *  Paolo Bonzini     <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+#ifndef TEST_IOTHREAD_H
+#define TEST_IOTHREAD_H
+
+#include "block/aio.h"
+#include "qemu/thread.h"
+
+typedef struct IOThread IOThread;
+
+IOThread *iothread_new(void);
+void iothread_join(IOThread *iothread);
+AioContext *iothread_get_aio_context(IOThread *iothread);
+
+#endif
diff --git a/tests/iothread.c b/tests/iothread.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/tests/iothread.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * Event loop thread implementation for unit tests
+ *
+ * Copyright Red Hat Inc., 2013, 2016
+ *
+ * Authors:
+ *  Stefan Hajnoczi   <stefanha@redhat.com>
+ *  Paolo Bonzini     <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "block/aio.h"
+#include "qemu/main-loop.h"
+#include "qemu/rcu.h"
+#include "iothread.h"
+
+struct IOThread {
+    AioContext *ctx;
+
+    QemuThread thread;
+    QemuMutex init_done_lock;
+    QemuCond init_done_cond;    /* is thread initialization done? */
+    bool stopping;
+};
+
+static __thread IOThread *my_iothread;
+
+AioContext *qemu_get_current_aio_context(void)
+{
+    return my_iothread ? my_iothread->ctx : qemu_get_aio_context();
+}
+
+static void *iothread_run(void *opaque)
+{
+    IOThread *iothread = opaque;
+
+    rcu_register_thread();
+
+    my_iothread = iothread;
+    qemu_mutex_lock(&iothread->init_done_lock);
+    iothread->ctx = aio_context_new(&error_abort);
+    qemu_cond_signal(&iothread->init_done_cond);
+    qemu_mutex_unlock(&iothread->init_done_lock);
+
+    while (!atomic_read(&iothread->stopping)) {
+        aio_poll(iothread->ctx, true);
+    }
+
+    rcu_unregister_thread();
+    return NULL;
+}
+
+void iothread_join(IOThread *iothread)
+{
+    iothread->stopping = true;
+    aio_notify(iothread->ctx);
+    qemu_thread_join(&iothread->thread);
+    qemu_cond_destroy(&iothread->init_done_cond);
+    qemu_mutex_destroy(&iothread->init_done_lock);
+    aio_context_unref(iothread->ctx);
+    g_free(iothread);
+}
+
+IOThread *iothread_new(void)
+{
+    IOThread *iothread = g_new0(IOThread, 1);
+
+    qemu_mutex_init(&iothread->init_done_lock);
+    qemu_cond_init(&iothread->init_done_cond);
+    qemu_thread_create(&iothread->thread, NULL, iothread_run,
+                       iothread, QEMU_THREAD_JOINABLE);
+
+    /* Wait for initialization to complete */
+    qemu_mutex_lock(&iothread->init_done_lock);
+    while (iothread->ctx == NULL) {
+        qemu_cond_wait(&iothread->init_done_cond,
+                       &iothread->init_done_lock);
+    }
+    qemu_mutex_unlock(&iothread->init_done_lock);
+    return iothread;
+}
+
+AioContext *iothread_get_aio_context(IOThread *iothread)
+{
+    return iothread->ctx;
+}
diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c
new file mode 100644
index XXXXXXX..XXXXXXX
--- /dev/null
+++ b/tests/test-aio-multithread.c
@@ -XXX,XX +XXX,XX @@
+/*
+ * AioContext multithreading tests
+ *
+ * Copyright Red Hat, Inc. 2016
+ *
+ * Authors:
+ *  Paolo Bonzini    <pbonzini@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2 or later.
+ * See the COPYING.LIB file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include <glib.h>
+#include "block/aio.h"
+#include "qapi/error.h"
+#include "qemu/coroutine.h"
+#include "qemu/thread.h"
+#include "qemu/error-report.h"
+#include "iothread.h"
+
+/* AioContext management */
+
+#define NUM_CONTEXTS 5
+
+static IOThread *threads[NUM_CONTEXTS];
+static AioContext *ctx[NUM_CONTEXTS];
+static __thread int id = -1;
+
+static QemuEvent done_event;
+
+/* Run a function synchronously on a remote iothread. */
+
+typedef struct CtxRunData {
+    QEMUBHFunc *cb;
+    void *arg;
+} CtxRunData;
+
+static void ctx_run_bh_cb(void *opaque)
+{
+    CtxRunData *data = opaque;
+
+    data->cb(data->arg);
+    qemu_event_set(&done_event);
+}
+
+static void ctx_run(int i, QEMUBHFunc *cb, void *opaque)
+{
+    CtxRunData data = {
+        .cb = cb,
+        .arg = opaque
+    };
+
+    qemu_event_reset(&done_event);
+    aio_bh_schedule_oneshot(ctx[i], ctx_run_bh_cb, &data);
+    qemu_event_wait(&done_event);
+}
+
+/* Starting the iothreads. */
+
+static void set_id_cb(void *opaque)
+{
+    int *i = opaque;
+
+    id = *i;
+}
+
+static void create_aio_contexts(void)
+{
+    int i;
+
+    for (i = 0; i < NUM_CONTEXTS; i++) {
+        threads[i] = iothread_new();
+        ctx[i] = iothread_get_aio_context(threads[i]);
+    }
+
+    qemu_event_init(&done_event, false);
+    for (i = 0; i < NUM_CONTEXTS; i++) {
+        ctx_run(i, set_id_cb, &i);
+    }
+}
+
+/* Stopping the iothreads. */
+
+static void join_aio_contexts(void)
+{
+    int i;
+
+    for (i = 0; i < NUM_CONTEXTS; i++) {
+        aio_context_ref(ctx[i]);
+    }
+    for (i = 0; i < NUM_CONTEXTS; i++) {
+        iothread_join(threads[i]);
+    }
+    for (i = 0; i < NUM_CONTEXTS; i++) {
+        aio_context_unref(ctx[i]);
+    }
+    qemu_event_destroy(&done_event);
+}
+
+/* Basic test for the stuff above. */
+
+static void test_lifecycle(void)
+{
+    create_aio_contexts();
+    join_aio_contexts();
+}
+
+/* aio_co_schedule test.  */
+
+static Coroutine *to_schedule[NUM_CONTEXTS];
+
+static bool now_stopping;
+
+static int count_retry;
+static int count_here;
+static int count_other;
+
+static bool schedule_next(int n)
+{
+    Coroutine *co;
+
+    co = atomic_xchg(&to_schedule[n], NULL);
+    if (!co) {
+        atomic_inc(&count_retry);
+        return false;
+    }
+
+    if (n == id) {
+        atomic_inc(&count_here);
+    } else {
+        atomic_inc(&count_other);
+    }
+
+    aio_co_schedule(ctx[n], co);
+    return true;
+}
+
+static void finish_cb(void *opaque)
+{
+    schedule_next(id);
+}
+
+static coroutine_fn void test_multi_co_schedule_entry(void *opaque)
+{
+    g_assert(to_schedule[id] == NULL);
+    atomic_mb_set(&to_schedule[id], qemu_coroutine_self());
+
+    while (!atomic_mb_read(&now_stopping)) {
+        int n;
+
+        n = g_test_rand_int_range(0, NUM_CONTEXTS);
+        schedule_next(n);
+        qemu_coroutine_yield();
+
+        g_assert(to_schedule[id] == NULL);
+        atomic_mb_set(&to_schedule[id], qemu_coroutine_self());
+    }
+}
+
+
+static void test_multi_co_schedule(int seconds)
+{
+    int i;
+
+    count_here = count_other = count_retry = 0;
+    now_stopping = false;
+
+    create_aio_contexts();
+    for (i = 0; i < NUM_CONTEXTS; i++) {
+        Coroutine *co1 = qemu_coroutine_create(test_multi_co_schedule_entry, NULL);
+        aio_co_schedule(ctx[i], co1);
+    }
+
+    g_usleep(seconds * 1000000);
+
+    atomic_mb_set(&now_stopping, true);
+    for (i = 0; i < NUM_CONTEXTS; i++) {
+        ctx_run(i, finish_cb, NULL);
+        to_schedule[i] = NULL;
+    }
+
+    join_aio_contexts();
+    g_test_message("scheduled %d, queued %d, retry %d, total %d\n",
+                  count_other, count_here, count_retry,
+                  count_here + count_other + count_retry);
+}
+
+static void test_multi_co_schedule_1(void)
+{
+    test_multi_co_schedule(1);
+}
+
+static void test_multi_co_schedule_10(void)
+{
+    test_multi_co_schedule(10);
+}
+
+/* End of tests.  */
+
+int main(int argc, char **argv)
+{
+    init_clocks();
+
+    g_test_init(&argc, &argv, NULL);
+    g_test_add_func("/aio/multi/lifecycle", test_lifecycle);
+    if (g_test_quick()) {
+        g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_1);
+    } else {
+        g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_10);
+    }
+    return g_test_run();
+}
diff --git a/util/async.c b/util/async.c
index XXXXXXX..XXXXXXX 100644
--- a/util/async.c
+++ b/util/async.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/main-loop.h"
 #include "qemu/atomic.h"
 #include "block/raw-aio.h"
+#include "qemu/coroutine_int.h"
+#include "trace.h"
 
 /***********************************************************/
 /* bottom halves (can be seen as timers which expire ASAP) */
@@ -XXX,XX +XXX,XX @@ aio_ctx_finalize(GSource     *source)
     }
 #endif
 
+    assert(QSLIST_EMPTY(&ctx->scheduled_coroutines));
+    qemu_bh_delete(ctx->co_schedule_bh);
+
     qemu_lockcnt_lock(&ctx->list_lock);
     assert(!qemu_lockcnt_count(&ctx->list_lock));
     while (ctx->first_bh) {
@@ -XXX,XX +XXX,XX @@ static bool event_notifier_poll(void *opaque)
     return atomic_read(&ctx->notified);
 }
 
+static void co_schedule_bh_cb(void *opaque)
+{
+    AioContext *ctx = opaque;
+    QSLIST_HEAD(, Coroutine) straight, reversed;
+
+    QSLIST_MOVE_ATOMIC(&reversed, &ctx->scheduled_coroutines);
+    QSLIST_INIT(&straight);
+
+    while (!QSLIST_EMPTY(&reversed)) {
+        Coroutine *co = QSLIST_FIRST(&reversed);
+        QSLIST_REMOVE_HEAD(&reversed, co_scheduled_next);
+        QSLIST_INSERT_HEAD(&straight, co, co_scheduled_next);
+    }
+
+    while (!QSLIST_EMPTY(&straight)) {
+        Coroutine *co = QSLIST_FIRST(&straight);
+        QSLIST_REMOVE_HEAD(&straight, co_scheduled_next);
+        trace_aio_co_schedule_bh_cb(ctx, co);
+        qemu_coroutine_enter(co);
+    }
+}
+
 AioContext *aio_context_new(Error **errp)
 {
     int ret;
@@ -XXX,XX +XXX,XX @@ AioContext *aio_context_new(Error **errp)
     }
     g_source_set_can_recurse(&ctx->source, true);
     qemu_lockcnt_init(&ctx->list_lock);
+
+    ctx->co_schedule_bh = aio_bh_new(ctx, co_schedule_bh_cb, ctx);
+    QSLIST_INIT(&ctx->scheduled_coroutines);
+
     aio_set_event_notifier(ctx, &ctx->notifier,
                            false,
                            (EventNotifierHandler *)
@@ -XXX,XX +XXX,XX @@ fail:
     return NULL;
 }
 
+void aio_co_schedule(AioContext *ctx, Coroutine *co)
+{
+    trace_aio_co_schedule(ctx, co);
+    QSLIST_INSERT_HEAD_ATOMIC(&ctx->scheduled_coroutines,
+                              co, co_scheduled_next);
+    qemu_bh_schedule(ctx->co_schedule_bh);
+}
+
+void aio_co_wake(struct Coroutine *co)
+{
+    AioContext *ctx;
+
+    /* Read coroutine before co->ctx.  Matches smp_wmb in
+     * qemu_coroutine_enter.
+     */
+    smp_read_barrier_depends();
+    ctx = atomic_read(&co->ctx);
+
+    if (ctx != qemu_get_current_aio_context()) {
+        aio_co_schedule(ctx, co);
+        return;
+    }
+
+    if (qemu_in_coroutine()) {
+        Coroutine *self = qemu_coroutine_self();
+        assert(self != co);
+        QSIMPLEQ_INSERT_TAIL(&self->co_queue_wakeup, co, co_queue_next);
+    } else {
+        aio_context_acquire(ctx);
+        qemu_coroutine_enter(co);
+        aio_context_release(ctx);
+    }
+}
+
 void aio_context_ref(AioContext *ctx)
 {
     g_source_ref(&ctx->source);
diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
index XXXXXXX..XXXXXXX 100644
--- a/util/qemu-coroutine.c
+++ b/util/qemu-coroutine.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/atomic.h"
 #include "qemu/coroutine.h"
 #include "qemu/coroutine_int.h"
+#include "block/aio.h"
 
 enum {
     POOL_BATCH_SIZE = 64,
@@ -XXX,XX +XXX,XX @@ void qemu_coroutine_enter(Coroutine *co)
     }
 
     co->caller = self;
+    co->ctx = qemu_get_current_aio_context();
+
+    /* Store co->ctx before anything that stores co.  Matches
+     * barrier in aio_co_wake.
+     */
+    smp_wmb();
+
     ret = qemu_coroutine_switch(self, co, COROUTINE_ENTER);
 
     qemu_co_queue_run_restart(co);
diff --git a/util/trace-events b/util/trace-events
index XXXXXXX..XXXXXXX 100644
--- a/util/trace-events
+++ b/util/trace-events
@@ -XXX,XX +XXX,XX @@ run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d"
 poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
 poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
 
+# util/async.c
+aio_co_schedule(void *ctx, void *co) "ctx %p co %p"
+aio_co_schedule_bh_cb(void *ctx, void *co) "ctx %p co %p"
+
 # util/thread-pool.c
 thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p"
 thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d"
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

qcow2_create2 calls this.  Do not run a nested event loop, as that
breaks when aio_co_wake tries to queue the coroutine on the co_queue_wakeup
list of the currently running one.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213135235.12274-4-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/block-backend.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -XXX,XX +XXX,XX @@ static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf,
 {
     QEMUIOVector qiov;
     struct iovec iov;
-    Coroutine *co;
     BlkRwCo rwco;
 
     iov = (struct iovec) {
@@ -XXX,XX +XXX,XX @@ static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf,
         .ret    = NOT_DONE,
     };
 
-    co = qemu_coroutine_create(co_entry, &rwco);
-    qemu_coroutine_enter(co);
-    BDRV_POLL_WHILE(blk_bs(blk), rwco.ret == NOT_DONE);
+    if (qemu_in_coroutine()) {
+        /* Fast-path if already in coroutine context */
+        co_entry(&rwco);
+    } else {
+        Coroutine *co = qemu_coroutine_create(co_entry, &rwco);
+        qemu_coroutine_enter(co);
+        BDRV_POLL_WHILE(blk_bs(blk), rwco.ret == NOT_DONE);
+    }
 
     return rwco.ret;
 }
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

Once the thread pool starts using aio_co_wake, it will also need
qemu_get_current_aio_context().  Make test-thread-pool create
an AioContext with qemu_init_main_loop, so that stubs/iothread.c
and tests/iothread.c can provide the rest.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213135235.12274-5-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/test-thread-pool.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/tests/test-thread-pool.c b/tests/test-thread-pool.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-thread-pool.c
+++ b/tests/test-thread-pool.c
@@ -XXX,XX +XXX,XX @@
 #include "qapi/error.h"
 #include "qemu/timer.h"
 #include "qemu/error-report.h"
+#include "qemu/main-loop.h"
 
 static AioContext *ctx;
 static ThreadPool *pool;
@@ -XXX,XX +XXX,XX @@ static void test_cancel_async(void)
 int main(int argc, char **argv)
 {
     int ret;
-    Error *local_error = NULL;
 
-    init_clocks();
-
-    ctx = aio_context_new(&local_error);
-    if (!ctx) {
-        error_reportf_err(local_error, "Failed to create AIO Context: ");
-        exit(1);
-    }
+    qemu_init_main_loop(&error_abort);
+    ctx = qemu_get_current_aio_context();
     pool = aio_get_thread_pool(ctx);
 
     g_test_init(&argc, &argv, NULL);
@@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv)
 
     ret = g_test_run();
 
-    aio_context_unref(ctx);
     return ret;
 }
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

This is in preparation for making qio_channel_yield work on
AioContexts other than the main one.

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213135235.12274-6-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/io/channel.h | 25 +++++++++++++++++++++++++
 io/channel-command.c | 13 +++++++++++++
 io/channel-file.c    | 11 +++++++++++
 io/channel-socket.c  | 16 +++++++++++-----
 io/channel-tls.c     | 12 ++++++++++++
 io/channel-watch.c   |  6 ++++++
 io/channel.c         | 11 +++++++++++
 7 files changed, 89 insertions(+), 5 deletions(-)

diff --git a/include/io/channel.h b/include/io/channel.h
index XXXXXXX..XXXXXXX 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -XXX,XX +XXX,XX @@
 
 #include "qemu-common.h"
 #include "qom/object.h"
+#include "block/aio.h"
 
 #define TYPE_QIO_CHANNEL "qio-channel"
 #define QIO_CHANNEL(obj)                                    \
@@ -XXX,XX +XXX,XX @@ struct QIOChannelClass {
                      off_t offset,
                      int whence,
                      Error **errp);
+    void (*io_set_aio_fd_handler)(QIOChannel *ioc,
+                                  AioContext *ctx,
+                                  IOHandler *io_read,
+                                  IOHandler *io_write,
+                                  void *opaque);
 };
 
 /* General I/O handling functions */
@@ -XXX,XX +XXX,XX @@ void qio_channel_yield(QIOChannel *ioc,
 void qio_channel_wait(QIOChannel *ioc,
                       GIOCondition condition);
 
+/**
+ * qio_channel_set_aio_fd_handler:
+ * @ioc: the channel object
+ * @ctx: the AioContext to set the handlers on
+ * @io_read: the read handler
+ * @io_write: the write handler
+ * @opaque: the opaque value passed to the handler
+ *
+ * This is used internally by qio_channel_yield().  It can
+ * be used by channel implementations to forward the handlers
+ * to another channel (e.g. from #QIOChannelTLS to the
+ * underlying socket).
+ */
+void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
+                                    AioContext *ctx,
+                                    IOHandler *io_read,
+                                    IOHandler *io_write,
+                                    void *opaque);
+
 #endif /* QIO_CHANNEL_H */
diff --git a/io/channel-command.c b/io/channel-command.c
index XXXXXXX..XXXXXXX 100644
--- a/io/channel-command.c
+++ b/io/channel-command.c
@@ -XXX,XX +XXX,XX @@ static int qio_channel_command_close(QIOChannel *ioc,
 }
 
 
+static void qio_channel_command_set_aio_fd_handler(QIOChannel *ioc,
+                                                   AioContext *ctx,
+                                                   IOHandler *io_read,
+                                                   IOHandler *io_write,
+                                                   void *opaque)
+{
+    QIOChannelCommand *cioc = QIO_CHANNEL_COMMAND(ioc);
+    aio_set_fd_handler(ctx, cioc->readfd, false, io_read, NULL, NULL, opaque);
+    aio_set_fd_handler(ctx, cioc->writefd, false, NULL, io_write, NULL, opaque);
+}
+
+
 static GSource *qio_channel_command_create_watch(QIOChannel *ioc,
                                                  GIOCondition condition)
 {
@@ -XXX,XX +XXX,XX @@ static void qio_channel_command_class_init(ObjectClass *klass,
     ioc_klass->io_set_blocking = qio_channel_command_set_blocking;
     ioc_klass->io_close = qio_channel_command_close;
     ioc_klass->io_create_watch = qio_channel_command_create_watch;
+    ioc_klass->io_set_aio_fd_handler = qio_channel_command_set_aio_fd_handler;
 }
 
 static const TypeInfo qio_channel_command_info = {
diff --git a/io/channel-file.c b/io/channel-file.c
index XXXXXXX..XXXXXXX 100644
--- a/io/channel-file.c
+++ b/io/channel-file.c
@@ -XXX,XX +XXX,XX @@ static int qio_channel_file_close(QIOChannel *ioc,
 }
 
 
+static void qio_channel_file_set_aio_fd_handler(QIOChannel *ioc,
+                                                AioContext *ctx,
+                                                IOHandler *io_read,
+                                                IOHandler *io_write,
+                                                void *opaque)
+{
+    QIOChannelFile *fioc = QIO_CHANNEL_FILE(ioc);
+    aio_set_fd_handler(ctx, fioc->fd, false, io_read, io_write, NULL, opaque);
+}
+
 static GSource *qio_channel_file_create_watch(QIOChannel *ioc,
                                               GIOCondition condition)
 {
@@ -XXX,XX +XXX,XX @@ static void qio_channel_file_class_init(ObjectClass *klass,
     ioc_klass->io_seek = qio_channel_file_seek;
     ioc_klass->io_close = qio_channel_file_close;
     ioc_klass->io_create_watch = qio_channel_file_create_watch;
+    ioc_klass->io_set_aio_fd_handler = qio_channel_file_set_aio_fd_handler;
 }
 
 static const TypeInfo qio_channel_file_info = {
diff --git a/io/channel-socket.c b/io/channel-socket.c
index XXXXXXX..XXXXXXX 100644
--- a/io/channel-socket.c
+++ b/io/channel-socket.c
@@ -XXX,XX +XXX,XX @@ qio_channel_socket_set_blocking(QIOChannel *ioc,
         qemu_set_block(sioc->fd);
     } else {
         qemu_set_nonblock(sioc->fd);
-#ifdef WIN32
-        WSAEventSelect(sioc->fd, ioc->event,
-                       FD_READ | FD_ACCEPT | FD_CLOSE |
-                       FD_CONNECT | FD_WRITE | FD_OOB);
-#endif
     }
     return 0;
 }
@@ -XXX,XX +XXX,XX @@ qio_channel_socket_shutdown(QIOChannel *ioc,
     return 0;
 }
 
+static void qio_channel_socket_set_aio_fd_handler(QIOChannel *ioc,
+                                                  AioContext *ctx,
+                                                  IOHandler *io_read,
+                                                  IOHandler *io_write,
+                                                  void *opaque)
+{
+    QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc);
+    aio_set_fd_handler(ctx, sioc->fd, false, io_read, io_write, NULL, opaque);
+}
+
 static GSource *qio_channel_socket_create_watch(QIOChannel *ioc,
                                                 GIOCondition condition)
 {
@@ -XXX,XX +XXX,XX @@ static void qio_channel_socket_class_init(ObjectClass *klass,
     ioc_klass->io_set_cork = qio_channel_socket_set_cork;
     ioc_klass->io_set_delay = qio_channel_socket_set_delay;
     ioc_klass->io_create_watch = qio_channel_socket_create_watch;
+    ioc_klass->io_set_aio_fd_handler = qio_channel_socket_set_aio_fd_handler;
 }
 
 static const TypeInfo qio_channel_socket_info = {
diff --git a/io/channel-tls.c b/io/channel-tls.c
index XXXXXXX..XXXXXXX 100644
--- a/io/channel-tls.c
+++ b/io/channel-tls.c
@@ -XXX,XX +XXX,XX @@ static int qio_channel_tls_close(QIOChannel *ioc,
     return qio_channel_close(tioc->master, errp);
 }
 
+static void qio_channel_tls_set_aio_fd_handler(QIOChannel *ioc,
+                                               AioContext *ctx,
+                                               IOHandler *io_read,
+                                               IOHandler *io_write,
+                                               void *opaque)
+{
+    QIOChannelTLS *tioc = QIO_CHANNEL_TLS(ioc);
+
+    qio_channel_set_aio_fd_handler(tioc->master, ctx, io_read, io_write, opaque);
+}
+
 static GSource *qio_channel_tls_create_watch(QIOChannel *ioc,
                                              GIOCondition condition)
 {
@@ -XXX,XX +XXX,XX @@ static void qio_channel_tls_class_init(ObjectClass *klass,
     ioc_klass->io_close = qio_channel_tls_close;
     ioc_klass->io_shutdown = qio_channel_tls_shutdown;
     ioc_klass->io_create_watch = qio_channel_tls_create_watch;
+    ioc_klass->io_set_aio_fd_handler = qio_channel_tls_set_aio_fd_handler;
 }
 
 static const TypeInfo qio_channel_tls_info = {
diff --git a/io/channel-watch.c b/io/channel-watch.c
index XXXXXXX..XXXXXXX 100644
--- a/io/channel-watch.c
+++ b/io/channel-watch.c
@@ -XXX,XX +XXX,XX @@ GSource *qio_channel_create_socket_watch(QIOChannel *ioc,
     GSource *source;
     QIOChannelSocketSource *ssource;
 
+#ifdef WIN32
+    WSAEventSelect(socket, ioc->event,
+                   FD_READ | FD_ACCEPT | FD_CLOSE |
+                   FD_CONNECT | FD_WRITE | FD_OOB);
+#endif
+
     source = g_source_new(&qio_channel_socket_source_funcs,
                           sizeof(QIOChannelSocketSource));
     ssource = (QIOChannelSocketSource *)source;
diff --git a/io/channel.c b/io/channel.c
index XXXXXXX..XXXXXXX 100644
--- a/io/channel.c
+++ b/io/channel.c
@@ -XXX,XX +XXX,XX @@ GSource *qio_channel_create_watch(QIOChannel *ioc,
 }
 
 
+void qio_channel_set_aio_fd_handler(QIOChannel *ioc,
+                                    AioContext *ctx,
+                                    IOHandler *io_read,
+                                    IOHandler *io_write,
+                                    void *opaque)
+{
+    QIOChannelClass *klass = QIO_CHANNEL_GET_CLASS(ioc);
+
+    klass->io_set_aio_fd_handler(ioc, ctx, io_read, io_write, opaque);
+}
+
 guint qio_channel_add_watch(QIOChannel *ioc,
                             GIOCondition condition,
                             QIOChannelFunc func,
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

Support separate coroutines for reading and writing, and place the
read/write handlers on the AioContext that the QIOChannel is registered
with.

Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213135235.12274-7-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/io/channel.h | 47 ++++++++++++++++++++++++++--
 io/channel.c         | 86 +++++++++++++++++++++++++++++++++++++++-------------
 2 files changed, 109 insertions(+), 24 deletions(-)

diff --git a/include/io/channel.h b/include/io/channel.h
index XXXXXXX..XXXXXXX 100644
--- a/include/io/channel.h
+++ b/include/io/channel.h
@@ -XXX,XX +XXX,XX @@
 
 #include "qemu-common.h"
 #include "qom/object.h"
+#include "qemu/coroutine.h"
 #include "block/aio.h"
 
 #define TYPE_QIO_CHANNEL "qio-channel"
@@ -XXX,XX +XXX,XX @@ struct QIOChannel {
     Object parent;
     unsigned int features; /* bitmask of QIOChannelFeatures */
     char *name;
+    AioContext *ctx;
+    Coroutine *read_coroutine;
+    Coroutine *write_coroutine;
 #ifdef _WIN32
     HANDLE event; /* For use with GSource on Win32 */
 #endif
@@ -XXX,XX +XXX,XX @@ guint qio_channel_add_watch(QIOChannel *ioc,
 
 
 /**
+ * qio_channel_attach_aio_context:
+ * @ioc: the channel object
+ * @ctx: the #AioContext to set the handlers on
+ *
+ * Request that qio_channel_yield() sets I/O handlers on
+ * the given #AioContext.  If @ctx is %NULL, qio_channel_yield()
+ * uses QEMU's main thread event loop.
+ *
+ * You can move a #QIOChannel from one #AioContext to another even if
+ * I/O handlers are set for a coroutine.  However, #QIOChannel provides
+ * no synchronization between the calls to qio_channel_yield() and
+ * qio_channel_attach_aio_context().
+ *
+ * Therefore you should first call qio_channel_detach_aio_context()
+ * to ensure that the coroutine is not entered concurrently.  Then,
+ * while the coroutine has yielded, call qio_channel_attach_aio_context(),
+ * and then aio_co_schedule() to place the coroutine on the new
+ * #AioContext.  The calls to qio_channel_detach_aio_context()
+ * and qio_channel_attach_aio_context() should be protected with
+ * aio_context_acquire() and aio_context_release().
+ */
+void qio_channel_attach_aio_context(QIOChannel *ioc,
+                                    AioContext *ctx);
+
+/**
+ * qio_channel_detach_aio_context:
+ * @ioc: the channel object
+ *
+ * Disable any I/O handlers set by qio_channel_yield().  With the
+ * help of aio_co_schedule(), this allows moving a coroutine that was
+ * paused by qio_channel_yield() to another context.
+ */
+void qio_channel_detach_aio_context(QIOChannel *ioc);
+
+/**
  * qio_channel_yield:
  * @ioc: the channel object
  * @condition: the I/O condition to wait for
  *
- * Yields execution from the current coroutine until
- * the condition indicated by @condition becomes
- * available.
+ * Yields execution from the current coroutine until the condition
+ * indicated by @condition becomes available.  @condition must
+ * be either %G_IO_IN or %G_IO_OUT; it cannot contain both.  In
+ * addition, no two coroutine can be waiting on the same condition
+ * and channel at the same time.
  *
  * This must only be called from coroutine context
  */
diff --git a/io/channel.c b/io/channel.c
index XXXXXXX..XXXXXXX 100644
--- a/io/channel.c
+++ b/io/channel.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/osdep.h"
 #include "io/channel.h"
 #include "qapi/error.h"
-#include "qemu/coroutine.h"
+#include "qemu/main-loop.h"
 
 bool qio_channel_has_feature(QIOChannel *ioc,
                              QIOChannelFeature feature)
@@ -XXX,XX +XXX,XX @@ off_t qio_channel_io_seek(QIOChannel *ioc,
 }
 
 
-typedef struct QIOChannelYieldData QIOChannelYieldData;
-struct QIOChannelYieldData {
-    QIOChannel *ioc;
-    Coroutine *co;
-};
+static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc);
 
+static void qio_channel_restart_read(void *opaque)
+{
+    QIOChannel *ioc = opaque;
+    Coroutine *co = ioc->read_coroutine;
+
+    ioc->read_coroutine = NULL;
+    qio_channel_set_aio_fd_handlers(ioc);
+    aio_co_wake(co);
+}
 
-static gboolean qio_channel_yield_enter(QIOChannel *ioc,
-                                        GIOCondition condition,
-                                        gpointer opaque)
+static void qio_channel_restart_write(void *opaque)
 {
-    QIOChannelYieldData *data = opaque;
-    qemu_coroutine_enter(data->co);
-    return FALSE;
+    QIOChannel *ioc = opaque;
+    Coroutine *co = ioc->write_coroutine;
+
+    ioc->write_coroutine = NULL;
+    qio_channel_set_aio_fd_handlers(ioc);
+    aio_co_wake(co);
 }
 
+static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc)
+{
+    IOHandler *rd_handler = NULL, *wr_handler = NULL;
+    AioContext *ctx;
+
+    if (ioc->read_coroutine) {
+        rd_handler = qio_channel_restart_read;
+    }
+    if (ioc->write_coroutine) {
+        wr_handler = qio_channel_restart_write;
+    }
+
+    ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
+    qio_channel_set_aio_fd_handler(ioc, ctx, rd_handler, wr_handler, ioc);
+}
+
+void qio_channel_attach_aio_context(QIOChannel *ioc,
+                                    AioContext *ctx)
+{
+    AioContext *old_ctx;
+    if (ioc->ctx == ctx) {
+        return;
+    }
+
+    old_ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context();
+    qio_channel_set_aio_fd_handler(ioc, old_ctx, NULL, NULL, NULL);
+    ioc->ctx = ctx;
+    qio_channel_set_aio_fd_handlers(ioc);
+}
+
+void qio_channel_detach_aio_context(QIOChannel *ioc)
+{
+    ioc->read_coroutine = NULL;
+    ioc->write_coroutine = NULL;
+    qio_channel_set_aio_fd_handlers(ioc);
+    ioc->ctx = NULL;
+}
 
 void coroutine_fn qio_channel_yield(QIOChannel *ioc,
                                     GIOCondition condition)
 {
-    QIOChannelYieldData data;
-
     assert(qemu_in_coroutine());
-    data.ioc = ioc;
-    data.co = qemu_coroutine_self();
-    qio_channel_add_watch(ioc,
-                          condition,
-                          qio_channel_yield_enter,
-                          &data,
-                          NULL);
+    if (condition == G_IO_IN) {
+        assert(!ioc->read_coroutine);
+        ioc->read_coroutine = qemu_coroutine_self();
+    } else if (condition == G_IO_OUT) {
+        assert(!ioc->write_coroutine);
+        ioc->write_coroutine = qemu_coroutine_self();
+    } else {
+        abort();
+    }
+    qio_channel_set_aio_fd_handlers(ioc);
     qemu_coroutine_yield();
 }
 
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

In the client, read the reply headers from a coroutine, switching the
read side between the "read header" coroutine and the I/O coroutine that
reads the body of the reply.

In the server, if the server can read more requests it will create a new
"read request" coroutine as soon as a request has been read.  Otherwise,
the new coroutine is created in nbd_request_put.

diff --git a/block/nbd-client.h b/block/nbd-client.h
index XXXXXXX..XXXXXXX 100644
--- a/block/nbd-client.h
+++ b/block/nbd-client.h
@@ -XXX,XX +XXX,XX @@ typedef struct NBDClientSession {
 
     CoMutex send_mutex;
     CoQueue free_sema;
-    Coroutine *send_coroutine;
+    Coroutine *read_reply_co;
     int in_flight;
 
     Coroutine *recv_coroutine[MAX_NBD_REQUESTS];
diff --git a/block/nbd-client.c b/block/nbd-client.c
index XXXXXXX..XXXXXXX 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -XXX,XX +XXX,XX @@
 #define HANDLE_TO_INDEX(bs, handle) ((handle) ^ ((uint64_t)(intptr_t)bs))
 #define INDEX_TO_HANDLE(bs, index)  ((index)  ^ ((uint64_t)(intptr_t)bs))
 
-static void nbd_recv_coroutines_enter_all(NBDClientSession *s)
+static void nbd_recv_coroutines_enter_all(BlockDriverState *bs)
 {
+    NBDClientSession *s = nbd_get_client_session(bs);
     int i;
 
     for (i = 0; i < MAX_NBD_REQUESTS; i++) {
@@ -XXX,XX +XXX,XX @@ static void nbd_recv_coroutines_enter_all(NBDClientSession *s)
             qemu_coroutine_enter(s->recv_coroutine[i]);
         }
     }
+    BDRV_POLL_WHILE(bs, s->read_reply_co);
 }
 
 static void nbd_teardown_connection(BlockDriverState *bs)
@@ -XXX,XX +XXX,XX @@ static void nbd_teardown_connection(BlockDriverState *bs)
     qio_channel_shutdown(client->ioc,
                          QIO_CHANNEL_SHUTDOWN_BOTH,
                          NULL);
-    nbd_recv_coroutines_enter_all(client);
+    nbd_recv_coroutines_enter_all(bs);
 
     nbd_client_detach_aio_context(bs);
     object_unref(OBJECT(client->sioc));
@@ -XXX,XX +XXX,XX @@ static void nbd_teardown_connection(BlockDriverState *bs)
     client->ioc = NULL;
 }
 
-static void nbd_reply_ready(void *opaque)
+static coroutine_fn void nbd_read_reply_entry(void *opaque)
 {
-    BlockDriverState *bs = opaque;
-    NBDClientSession *s = nbd_get_client_session(bs);
+    NBDClientSession *s = opaque;
     uint64_t i;
     int ret;
 
-    if (!s->ioc) { /* Already closed */
-        return;
-    }
-
-    if (s->reply.handle == 0) {
-        /* No reply already in flight.  Fetch a header.  It is possible
-         * that another thread has done the same thing in parallel, so
-         * the socket is not readable anymore.
-         */
+    for (;;) {
+        assert(s->reply.handle == 0);
         ret = nbd_receive_reply(s->ioc, &s->reply);
-        if (ret == -EAGAIN) {
-            return;
-        }
         if (ret < 0) {
-            s->reply.handle = 0;
-            goto fail;
+            break;
         }
-    }
 
-    /* There's no need for a mutex on the receive side, because the
-     * handler acts as a synchronization point and ensures that only
-     * one coroutine is called until the reply finishes.  */
-    i = HANDLE_TO_INDEX(s, s->reply.handle);
-    if (i >= MAX_NBD_REQUESTS) {
-        goto fail;
-    }
+        /* There's no need for a mutex on the receive side, because the
+         * handler acts as a synchronization point and ensures that only
+         * one coroutine is called until the reply finishes.
+         */
+        i = HANDLE_TO_INDEX(s, s->reply.handle);
+        if (i >= MAX_NBD_REQUESTS || !s->recv_coroutine[i]) {
+            break;
+        }
 
-    if (s->recv_coroutine[i]) {
-        qemu_coroutine_enter(s->recv_coroutine[i]);
-        return;
+        /* We're woken up by the recv_coroutine itself.  Note that there
+         * is no race between yielding and reentering read_reply_co.  This
+         * is because:
+         *
+         * - if recv_coroutine[i] runs on the same AioContext, it is only
+         *   entered after we yield
+         *
+         * - if recv_coroutine[i] runs on a different AioContext, reentering
+         *   read_reply_co happens through a bottom half, which can only
+         *   run after we yield.
+         */
+        aio_co_wake(s->recv_coroutine[i]);
+        qemu_coroutine_yield();
     }
-
-fail:
-    nbd_teardown_connection(bs);
-}
-
-static void nbd_restart_write(void *opaque)
-{
-    BlockDriverState *bs = opaque;
-
-    qemu_coroutine_enter(nbd_get_client_session(bs)->send_coroutine);
+    s->read_reply_co = NULL;
 }
 
 static int nbd_co_send_request(BlockDriverState *bs,
@@ -XXX,XX +XXX,XX @@ static int nbd_co_send_request(BlockDriverState *bs,
                                QEMUIOVector *qiov)
 {
     NBDClientSession *s = nbd_get_client_session(bs);
-    AioContext *aio_context;
     int rc, ret, i;
 
     qemu_co_mutex_lock(&s->send_mutex);
@@ -XXX,XX +XXX,XX @@ static int nbd_co_send_request(BlockDriverState *bs,
         return -EPIPE;
     }
 
-    s->send_coroutine = qemu_coroutine_self();
-    aio_context = bdrv_get_aio_context(bs);
-
-    aio_set_fd_handler(aio_context, s->sioc->fd, false,
-                       nbd_reply_ready, nbd_restart_write, NULL, bs);
     if (qiov) {
         qio_channel_set_cork(s->ioc, true);
         rc = nbd_send_request(s->ioc, request);
@@ -XXX,XX +XXX,XX @@ static int nbd_co_send_request(BlockDriverState *bs,
     } else {
         rc = nbd_send_request(s->ioc, request);
     }
-    aio_set_fd_handler(aio_context, s->sioc->fd, false,
-                       nbd_reply_ready, NULL, NULL, bs);
-    s->send_coroutine = NULL;
     qemu_co_mutex_unlock(&s->send_mutex);
     return rc;
 }
@@ -XXX,XX +XXX,XX @@ static void nbd_co_receive_reply(NBDClientSession *s,
 {
     int ret;
 
-    /* Wait until we're woken up by the read handler.  TODO: perhaps
-     * peek at the next reply and avoid yielding if it's ours?  */
+    /* Wait until we're woken up by nbd_read_reply_entry.  */
     qemu_coroutine_yield();
     *reply = s->reply;
     if (reply->handle != request->handle ||
@@ -XXX,XX +XXX,XX @@ static void nbd_coroutine_start(NBDClientSession *s,
     /* s->recv_coroutine[i] is set as soon as we get the send_lock.  */
 }
 
-static void nbd_coroutine_end(NBDClientSession *s,
+static void nbd_coroutine_end(BlockDriverState *bs,
                               NBDRequest *request)
 {
+    NBDClientSession *s = nbd_get_client_session(bs);
     int i = HANDLE_TO_INDEX(s, request->handle);
+
     s->recv_coroutine[i] = NULL;
-    if (s->in_flight-- == MAX_NBD_REQUESTS) {
-        qemu_co_queue_next(&s->free_sema);
+    s->in_flight--;
+    qemu_co_queue_next(&s->free_sema);
+
+    /* Kick the read_reply_co to get the next reply.  */
+    if (s->read_reply_co) {
+        aio_co_wake(s->read_reply_co);
     }
 }
 
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
     } else {
         nbd_co_receive_reply(client, &request, &reply, qiov);
     }
-    nbd_coroutine_end(client, &request);
+    nbd_coroutine_end(bs, &request);
     return -reply.error;
 }
 
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t offset,
     } else {
         nbd_co_receive_reply(client, &request, &reply, NULL);
     }
-    nbd_coroutine_end(client, &request);
+    nbd_coroutine_end(bs, &request);
     return -reply.error;
 }
 
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_pwrite_zeroes(BlockDriverState *bs, int64_t offset,
     } else {
         nbd_co_receive_reply(client, &request, &reply, NULL);
     }
-    nbd_coroutine_end(client, &request);
+    nbd_coroutine_end(bs, &request);
     return -reply.error;
 }
 
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_flush(BlockDriverState *bs)
     } else {
         nbd_co_receive_reply(client, &request, &reply, NULL);
     }
-    nbd_coroutine_end(client, &request);
+    nbd_coroutine_end(bs, &request);
     return -reply.error;
 }
 
@@ -XXX,XX +XXX,XX @@ int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t offset, int count)
     } else {
         nbd_co_receive_reply(client, &request, &reply, NULL);
     }
-    nbd_coroutine_end(client, &request);
+    nbd_coroutine_end(bs, &request);
     return -reply.error;
 
 }
 
 void nbd_client_detach_aio_context(BlockDriverState *bs)
 {
-    aio_set_fd_handler(bdrv_get_aio_context(bs),
-                       nbd_get_client_session(bs)->sioc->fd,
-                       false, NULL, NULL, NULL, NULL);
+    NBDClientSession *client = nbd_get_client_session(bs);
+    qio_channel_detach_aio_context(QIO_CHANNEL(client->sioc));
 }
 
 void nbd_client_attach_aio_context(BlockDriverState *bs,
                                    AioContext *new_context)
 {
-    aio_set_fd_handler(new_context, nbd_get_client_session(bs)->sioc->fd,
-                       false, nbd_reply_ready, NULL, NULL, bs);
+    NBDClientSession *client = nbd_get_client_session(bs);
+    qio_channel_attach_aio_context(QIO_CHANNEL(client->sioc), new_context);
+    aio_co_schedule(new_context, client->read_reply_co);
 }
 
 void nbd_client_close(BlockDriverState *bs)
@@ -XXX,XX +XXX,XX @@ int nbd_client_init(BlockDriverState *bs,
     /* Now that we're connected, set the socket to be non-blocking and
      * kick the reply mechanism.  */
     qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL);
-
+    client->read_reply_co = qemu_coroutine_create(nbd_read_reply_entry, client);
     nbd_client_attach_aio_context(bs, bdrv_get_aio_context(bs));
 
     logout("Established connection with NBD server\n");
diff --git a/nbd/client.c b/nbd/client.c
index XXXXXXX..XXXXXXX 100644
--- a/nbd/client.c
+++ b/nbd/client.c
@@ -XXX,XX +XXX,XX @@ ssize_t nbd_receive_reply(QIOChannel *ioc, NBDReply *reply)
     ssize_t ret;
 
     ret = read_sync(ioc, buf, sizeof(buf));
-    if (ret < 0) {
+    if (ret <= 0) {
         return ret;
     }
 
diff --git a/nbd/common.c b/nbd/common.c
index XXXXXXX..XXXXXXX 100644
--- a/nbd/common.c
+++ b/nbd/common.c
@@ -XXX,XX +XXX,XX @@ ssize_t nbd_wr_syncv(QIOChannel *ioc,
         }
         if (len == QIO_CHANNEL_ERR_BLOCK) {
             if (qemu_in_coroutine()) {
-                /* XXX figure out if we can create a variant on
-                 * qio_channel_yield() that works with AIO contexts
-                 * and consider using that in this branch */
-                qemu_coroutine_yield();
-            } else if (done) {
-                /* XXX this is needed by nbd_reply_ready.  */
-                qio_channel_wait(ioc,
-                                 do_read ? G_IO_IN : G_IO_OUT);
+                qio_channel_yield(ioc, do_read ? G_IO_IN : G_IO_OUT);
             } else {
                 return -EAGAIN;
             }
diff --git a/nbd/server.c b/nbd/server.c
index XXXXXXX..XXXXXXX 100644
--- a/nbd/server.c
+++ b/nbd/server.c
@@ -XXX,XX +XXX,XX @@ struct NBDClient {
     CoMutex send_lock;
     Coroutine *send_coroutine;
 
-    bool can_read;
-
     QTAILQ_ENTRY(NBDClient) next;
     int nb_requests;
     bool closing;
@@ -XXX,XX +XXX,XX @@ struct NBDClient {
 
 /* That's all folks */
 
-static void nbd_set_handlers(NBDClient *client);
-static void nbd_unset_handlers(NBDClient *client);
-static void nbd_update_can_read(NBDClient *client);
+static void nbd_client_receive_next_request(NBDClient *client);
 
 static gboolean nbd_negotiate_continue(QIOChannel *ioc,
                                        GIOCondition condition,
@@ -XXX,XX +XXX,XX @@ void nbd_client_put(NBDClient *client)
          */
         assert(client->closing);
 
-        nbd_unset_handlers(client);
+        qio_channel_detach_aio_context(client->ioc);
         object_unref(OBJECT(client->sioc));
         object_unref(OBJECT(client->ioc));
         if (client->tlscreds) {
@@ -XXX,XX +XXX,XX @@ static NBDRequestData *nbd_request_get(NBDClient *client)
 
     assert(client->nb_requests <= MAX_NBD_REQUESTS - 1);
     client->nb_requests++;
-    nbd_update_can_read(client);
 
     req = g_new0(NBDRequestData, 1);
     nbd_client_get(client);
@@ -XXX,XX +XXX,XX @@ static void nbd_request_put(NBDRequestData *req)
     g_free(req);
 
     client->nb_requests--;
-    nbd_update_can_read(client);
+    nbd_client_receive_next_request(client);
+
     nbd_client_put(client);
 }
 
@@ -XXX,XX +XXX,XX @@ static void blk_aio_attached(AioContext *ctx, void *opaque)
     exp->ctx = ctx;
 
     QTAILQ_FOREACH(client, &exp->clients, next) {
-        nbd_set_handlers(client);
+        qio_channel_attach_aio_context(client->ioc, ctx);
+        if (client->recv_coroutine) {
+            aio_co_schedule(ctx, client->recv_coroutine);
+        }
+        if (client->send_coroutine) {
+            aio_co_schedule(ctx, client->send_coroutine);
+        }
     }
 }
 
@@ -XXX,XX +XXX,XX @@ static void blk_aio_detach(void *opaque)
     TRACE("Export %s: Detaching clients from AIO context %p\n", exp->name, exp->ctx);
 
     QTAILQ_FOREACH(client, &exp->clients, next) {
-        nbd_unset_handlers(client);
+        qio_channel_detach_aio_context(client->ioc);
     }
 
     exp->ctx = NULL;
@@ -XXX,XX +XXX,XX @@ static ssize_t nbd_co_send_reply(NBDRequestData *req, NBDReply *reply,
     g_assert(qemu_in_coroutine());
     qemu_co_mutex_lock(&client->send_lock);
     client->send_coroutine = qemu_coroutine_self();
-    nbd_set_handlers(client);
 
     if (!len) {
         rc = nbd_send_reply(client->ioc, reply);
@@ -XXX,XX +XXX,XX @@ static ssize_t nbd_co_send_reply(NBDRequestData *req, NBDReply *reply,
     }
 
     client->send_coroutine = NULL;
-    nbd_set_handlers(client);
     qemu_co_mutex_unlock(&client->send_lock);
     return rc;
 }
@@ -XXX,XX +XXX,XX @@ static ssize_t nbd_co_receive_request(NBDRequestData *req,
     ssize_t rc;
 
     g_assert(qemu_in_coroutine());
-    client->recv_coroutine = qemu_coroutine_self();
-    nbd_update_can_read(client);
-
+    assert(client->recv_coroutine == qemu_coroutine_self());
     rc = nbd_receive_request(client->ioc, request);
     if (rc < 0) {
         if (rc != -EAGAIN) {
@@ -XXX,XX +XXX,XX @@ static ssize_t nbd_co_receive_request(NBDRequestData *req,
 
 out:
     client->recv_coroutine = NULL;
-    nbd_update_can_read(client);
+    nbd_client_receive_next_request(client);
 
     return rc;
 }
 
-static void nbd_trip(void *opaque)
+/* Owns a reference to the NBDClient passed as opaque.  */
+static coroutine_fn void nbd_trip(void *opaque)
 {
     NBDClient *client = opaque;
     NBDExport *exp = client->exp;
     NBDRequestData *req;
-    NBDRequest request;
+    NBDRequest request = { 0 };    /* GCC thinks it can be used uninitialized */
     NBDReply reply;
     ssize_t ret;
     int flags;
 
     TRACE("Reading request.");
     if (client->closing) {
+        nbd_client_put(client);
         return;
     }
 
@@ -XXX,XX +XXX,XX @@ static void nbd_trip(void *opaque)
 
 done:
     nbd_request_put(req);
+    nbd_client_put(client);
     return;
 
 out:
     nbd_request_put(req);
     client_close(client);
+    nbd_client_put(client);
 }
 
-static void nbd_read(void *opaque)
+static void nbd_client_receive_next_request(NBDClient *client)
 {
-    NBDClient *client = opaque;
-
-    if (client->recv_coroutine) {
-        qemu_coroutine_enter(client->recv_coroutine);
-    } else {
-        qemu_coroutine_enter(qemu_coroutine_create(nbd_trip, client));
-    }
-}
-
-static void nbd_restart_write(void *opaque)
-{
-    NBDClient *client = opaque;
-
-    qemu_coroutine_enter(client->send_coroutine);
-}
-
-static void nbd_set_handlers(NBDClient *client)
-{
-    if (client->exp && client->exp->ctx) {
-        aio_set_fd_handler(client->exp->ctx, client->sioc->fd, true,
-                           client->can_read ? nbd_read : NULL,
-                           client->send_coroutine ? nbd_restart_write : NULL,
-                           NULL, client);
-    }
-}
-
-static void nbd_unset_handlers(NBDClient *client)
-{
-    if (client->exp && client->exp->ctx) {
-        aio_set_fd_handler(client->exp->ctx, client->sioc->fd, true, NULL,
-                           NULL, NULL, NULL);
-    }
-}
-
-static void nbd_update_can_read(NBDClient *client)
-{
-    bool can_read = client->recv_coroutine ||
-                    client->nb_requests < MAX_NBD_REQUESTS;
-
-    if (can_read != client->can_read) {
-        client->can_read = can_read;
-        nbd_set_handlers(client);
-
-        /* There is no need to invoke aio_notify(), since aio_set_fd_handler()
-         * in nbd_set_handlers() will have taken care of that */
+    if (!client->recv_coroutine && client->nb_requests < MAX_NBD_REQUESTS) {
+        nbd_client_get(client);
+        client->recv_coroutine = qemu_coroutine_create(nbd_trip, client);
+        aio_co_schedule(client->exp->ctx, client->recv_coroutine);
     }
 }
 
@@ -XXX,XX +XXX,XX @@ static coroutine_fn void nbd_co_client_start(void *opaque)
         goto out;
     }
     qemu_co_mutex_init(&client->send_lock);
-    nbd_set_handlers(client);
 
     if (exp) {
         QTAILQ_INSERT_TAIL(&exp->clients, client, next);
     }
+
+    nbd_client_receive_next_request(client);
+
 out:
     g_free(data);
 }
@@ -XXX,XX +XXX,XX @@ void nbd_client_new(NBDExport *exp,
     object_ref(OBJECT(client->sioc));
     client->ioc = QIO_CHANNEL(sioc);
     object_ref(OBJECT(client->ioc));
-    client->can_read = true;
     client->close = close_fn;
 
     data->client = client;
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

As a small step towards the introduction of multiqueue, we want
coroutines to remain on the same AioContext that started them,
unless they are moved explicitly with e.g. aio_co_schedule.  This patch
avoids that coroutines switch AioContext when they use a CoMutex.
For now it does not make much of a difference, because the CoMutex
is not thread-safe and the AioContext itself is used to protect the
CoMutex from concurrent access.  However, this is going to change.

diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index XXXXXXX..XXXXXXX 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu/coroutine.h"
 #include "qemu/coroutine_int.h"
 #include "qemu/queue.h"
+#include "block/aio.h"
 #include "trace.h"
 
 void qemu_co_queue_init(CoQueue *queue)
@@ -XXX,XX +XXX,XX @@ void qemu_co_queue_run_restart(Coroutine *co)
 
 static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
 {
-    Coroutine *self = qemu_coroutine_self();
     Coroutine *next;
 
     if (QSIMPLEQ_EMPTY(&queue->entries)) {
@@ -XXX,XX +XXX,XX @@ static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
 
     while ((next = QSIMPLEQ_FIRST(&queue->entries)) != NULL) {
         QSIMPLEQ_REMOVE_HEAD(&queue->entries, co_queue_next);
-        QSIMPLEQ_INSERT_TAIL(&self->co_queue_wakeup, next, co_queue_next);
-        trace_qemu_co_queue_next(next);
+        aio_co_wake(next);
         if (single) {
             break;
         }
diff --git a/util/trace-events b/util/trace-events
index XXXXXXX..XXXXXXX 100644
--- a/util/trace-events
+++ b/util/trace-events
@@ -XXX,XX +XXX,XX @@ qemu_coroutine_terminate(void *co) "self %p"
 
 # util/qemu-coroutine-lock.c
 qemu_co_queue_run_restart(void *co) "co %p"
-qemu_co_queue_next(void *nxt) "next %p"
 qemu_co_mutex_lock_entry(void *mutex, void *self) "mutex %p self %p"
 qemu_co_mutex_lock_return(void *mutex, void *self) "mutex %p self %p"
 qemu_co_mutex_unlock_entry(void *mutex, void *self) "mutex %p self %p"
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

Keep the coroutine on the same AioContext.  Without this change,
there would be a race between yielding the coroutine and reentering it.
While the race cannot happen now, because the code only runs from a single
AioContext, this will change with multiqueue support in the block layer.

While doing the change, replace custom bottom half with aio_co_schedule.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-10-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/blkdebug.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/block/blkdebug.c b/block/blkdebug.c
index XXXXXXX..XXXXXXX 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -XXX,XX +XXX,XX @@ out:
     return ret;
 }
 
-static void error_callback_bh(void *opaque)
-{
-    Coroutine *co = opaque;
-    qemu_coroutine_enter(co);
-}
-
 static int inject_error(BlockDriverState *bs, BlkdebugRule *rule)
 {
     BDRVBlkdebugState *s = bs->opaque;
@@ -XXX,XX +XXX,XX @@ static int inject_error(BlockDriverState *bs, BlkdebugRule *rule)
     }
 
     if (!immediately) {
-        aio_bh_schedule_oneshot(bdrv_get_aio_context(bs), error_callback_bh,
-                                qemu_coroutine_self());
+        aio_co_schedule(qemu_get_current_aio_context(), qemu_coroutine_self());
         qemu_coroutine_yield();
     }
 
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

qed_aio_start_io and qed_aio_next_io will not have to acquire/release
the AioContext, while qed_aio_next_io_cb will.  Split the functionality
and gain a little type-safety in the process.

diff --git a/block/qed.c b/block/qed.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -XXX,XX +XXX,XX @@ static CachedL2Table *qed_new_l2_table(BDRVQEDState *s)
     return l2_table;
 }
 
-static void qed_aio_next_io(void *opaque, int ret);
+static void qed_aio_next_io(QEDAIOCB *acb, int ret);
+
+static void qed_aio_start_io(QEDAIOCB *acb)
+{
+    qed_aio_next_io(acb, 0);
+}
+
+static void qed_aio_next_io_cb(void *opaque, int ret)
+{
+    QEDAIOCB *acb = opaque;
+
+    qed_aio_next_io(acb, ret);
+}
 
 static void qed_plug_allocating_write_reqs(BDRVQEDState *s)
 {
@@ -XXX,XX +XXX,XX @@ static void qed_unplug_allocating_write_reqs(BDRVQEDState *s)
 
     acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs);
     if (acb) {
-        qed_aio_next_io(acb, 0);
+        qed_aio_start_io(acb);
     }
 }
 
@@ -XXX,XX +XXX,XX @@ static void qed_aio_complete(QEDAIOCB *acb, int ret)
         QSIMPLEQ_REMOVE_HEAD(&s->allocating_write_reqs, next);
         acb = QSIMPLEQ_FIRST(&s->allocating_write_reqs);
         if (acb) {
-            qed_aio_next_io(acb, 0);
+            qed_aio_start_io(acb);
         } else if (s->header.features & QED_F_NEED_CHECK) {
             qed_start_need_check_timer(s);
         }
@@ -XXX,XX +XXX,XX @@ static void qed_commit_l2_update(void *opaque, int ret)
     acb->request.l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
     assert(acb->request.l2_table != NULL);
 
-    qed_aio_next_io(opaque, ret);
+    qed_aio_next_io(acb, ret);
 }
 
 /**
@@ -XXX,XX +XXX,XX @@ static void qed_aio_write_l2_update(QEDAIOCB *acb, int ret, uint64_t offset)
     if (need_alloc) {
         /* Write out the whole new L2 table */
         qed_write_l2_table(s, &acb->request, 0, s->table_nelems, true,
-                            qed_aio_write_l1_update, acb);
+                           qed_aio_write_l1_update, acb);
     } else {
         /* Write out only the updated part of the L2 table */
         qed_write_l2_table(s, &acb->request, index, acb->cur_nclusters, false,
-                            qed_aio_next_io, acb);
+                           qed_aio_next_io_cb, acb);
     }
     return;
 
@@ -XXX,XX +XXX,XX @@ static void qed_aio_write_main(void *opaque, int ret)
     }
 
     if (acb->find_cluster_ret == QED_CLUSTER_FOUND) {
-        next_fn = qed_aio_next_io;
+        next_fn = qed_aio_next_io_cb;
     } else {
         if (s->bs->backing) {
             next_fn = qed_aio_write_flush_before_l2_update;
@@ -XXX,XX +XXX,XX @@ static void qed_aio_write_alloc(QEDAIOCB *acb, size_t len)
     if (acb->flags & QED_AIOCB_ZERO) {
         /* Skip ahead if the clusters are already zero */
         if (acb->find_cluster_ret == QED_CLUSTER_ZERO) {
-            qed_aio_next_io(acb, 0);
+            qed_aio_start_io(acb);
             return;
         }
 
@@ -XXX,XX +XXX,XX @@ static void qed_aio_read_data(void *opaque, int ret,
     /* Handle zero cluster and backing file reads */
     if (ret == QED_CLUSTER_ZERO) {
         qemu_iovec_memset(&acb->cur_qiov, 0, 0, acb->cur_qiov.size);
-        qed_aio_next_io(acb, 0);
+        qed_aio_start_io(acb);
         return;
     } else if (ret != QED_CLUSTER_FOUND) {
         qed_read_backing_file(s, acb->cur_pos, &acb->cur_qiov,
-                              &acb->backing_qiov, qed_aio_next_io, acb);
+                              &acb->backing_qiov, qed_aio_next_io_cb, acb);
         return;
     }
 
     BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
     bdrv_aio_readv(bs->file, offset / BDRV_SECTOR_SIZE,
                    &acb->cur_qiov, acb->cur_qiov.size / BDRV_SECTOR_SIZE,
-                   qed_aio_next_io, acb);
+                   qed_aio_next_io_cb, acb);
     return;
 
 err:
@@ -XXX,XX +XXX,XX @@ err:
 /**
  * Begin next I/O or complete the request
  */
-static void qed_aio_next_io(void *opaque, int ret)
+static void qed_aio_next_io(QEDAIOCB *acb, int ret)
 {
-    QEDAIOCB *acb = opaque;
     BDRVQEDState *s = acb_to_s(acb);
     QEDFindClusterFunc *io_fn = (acb->flags & QED_AIOCB_WRITE) ?
                                 qed_aio_write_data : qed_aio_read_data;
@@ -XXX,XX +XXX,XX @@ static BlockAIOCB *qed_aio_setup(BlockDriverState *bs,
     qemu_iovec_init(&acb->cur_qiov, qiov->niov);
 
     /* Start request */
-    qed_aio_next_io(acb, 0);
+    qed_aio_start_io(acb);
     return &acb->common;
 }
 
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

The AioContext data structures are now protected by list_lock and/or
they are walked with FOREACH_RCU primitives.  There is no need anymore
to acquire the AioContext for the entire duration of aio_dispatch.
Instead, just acquire it before and after invoking the callbacks.
The next step is then to push it further down.

diff --git a/util/aio-posix.c b/util/aio-posix.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
             (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) &&
             aio_node_check(ctx, node->is_external) &&
             node->io_read) {
+            aio_context_acquire(ctx);
             node->io_read(node->opaque);
+            aio_context_release(ctx);
 
             /* aio_notify() does not count as progress */
             if (node->opaque != &ctx->notifier) {
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
             (revents & (G_IO_OUT | G_IO_ERR)) &&
             aio_node_check(ctx, node->is_external) &&
             node->io_write) {
+            aio_context_acquire(ctx);
             node->io_write(node->opaque);
+            aio_context_release(ctx);
             progress = true;
         }
 
@@ -XXX,XX +XXX,XX @@ bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
     }
 
     /* Run our timers */
+    aio_context_acquire(ctx);
     progress |= timerlistgroup_run_timers(&ctx->tlg);
+    aio_context_release(ctx);
 
     return progress;
 }
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
     int64_t timeout;
     int64_t start = 0;
 
-    aio_context_acquire(ctx);
-    progress = false;
-
     /* aio_notify can avoid the expensive event_notifier_set if
      * everything (file descriptors, bottom halves, timers) will
      * be re-evaluated before the next blocking poll().  This is
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
         start = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
     }
 
-    if (try_poll_mode(ctx, blocking)) {
-        progress = true;
-    } else {
+    aio_context_acquire(ctx);
+    progress = try_poll_mode(ctx, blocking);
+    aio_context_release(ctx);
+
+    if (!progress) {
         assert(npfd == 0);
 
         /* fill pollfds */
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
         timeout = blocking ? aio_compute_timeout(ctx) : 0;
 
         /* wait until next event */
-        if (timeout) {
-            aio_context_release(ctx);
-        }
         if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) {
             AioHandler epoll_handler;
 
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
         } else  {
             ret = qemu_poll_ns(pollfds, npfd, timeout);
         }
-        if (timeout) {
-            aio_context_acquire(ctx);
-        }
     }
 
     if (blocking) {
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
         progress = true;
     }
 
-    aio_context_release(ctx);
-
     return progress;
 }
 
diff --git a/util/aio-win32.c b/util/aio-win32.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-win32.c
+++ b/util/aio-win32.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
             (revents || event_notifier_get_handle(node->e) == event) &&
             node->io_notify) {
             node->pfd.revents = 0;
+            aio_context_acquire(ctx);
             node->io_notify(node->e);
+            aio_context_release(ctx);
 
             /* aio_notify() does not count as progress */
             if (node->e != &ctx->notifier) {
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
             (node->io_read || node->io_write)) {
             node->pfd.revents = 0;
             if ((revents & G_IO_IN) && node->io_read) {
+                aio_context_acquire(ctx);
                 node->io_read(node->opaque);
+                aio_context_release(ctx);
                 progress = true;
             }
             if ((revents & G_IO_OUT) && node->io_write) {
+                aio_context_acquire(ctx);
                 node->io_write(node->opaque);
+                aio_context_release(ctx);
                 progress = true;
             }
 
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
     int count;
     int timeout;
 
-    aio_context_acquire(ctx);
     progress = false;
 
     /* aio_notify can avoid the expensive event_notifier_set if
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
 
         timeout = blocking && !have_select_revents
             ? qemu_timeout_ns_to_ms(aio_compute_timeout(ctx)) : 0;
-        if (timeout) {
-            aio_context_release(ctx);
-        }
         ret = WaitForMultipleObjects(count, events, FALSE, timeout);
         if (blocking) {
             assert(first);
             atomic_sub(&ctx->notify_me, 2);
         }
-        if (timeout) {
-            aio_context_acquire(ctx);
-        }
 
         if (first) {
             aio_notify_accept(ctx);
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
         progress |= aio_dispatch_handlers(ctx, event);
     } while (count > 0);
 
+    aio_context_acquire(ctx);
     progress |= timerlistgroup_run_timers(&ctx->tlg);
-
     aio_context_release(ctx);
     return progress;
 }
diff --git a/util/async.c b/util/async.c
index XXXXXXX..XXXXXXX 100644
--- a/util/async.c
+++ b/util/async.c
@@ -XXX,XX +XXX,XX @@ int aio_bh_poll(AioContext *ctx)
                 ret = 1;
             }
             bh->idle = 0;
+            aio_context_acquire(ctx);
             aio_bh_call(bh);
+            aio_context_release(ctx);
         }
         if (bh->deleted) {
             deleted = true;
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-13-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/qed.h                 |  3 +++
 block/curl.c                |  2 ++
 block/io.c                  |  5 +++++
 block/iscsi.c               |  8 ++++++--
 block/null.c                |  4 ++++
 block/qed.c                 | 12 ++++++++++++
 block/throttle-groups.c     |  2 ++
 util/aio-posix.c            |  2 --
 util/aio-win32.c            |  2 --
 util/qemu-coroutine-sleep.c |  2 +-
 10 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/block/qed.h b/block/qed.h
index XXXXXXX..XXXXXXX 100644
--- a/block/qed.h
+++ b/block/qed.h
@@ -XXX,XX +XXX,XX @@ enum {
  */
 typedef void QEDFindClusterFunc(void *opaque, int ret, uint64_t offset, size_t len);
 
+void qed_acquire(BDRVQEDState *s);
+void qed_release(BDRVQEDState *s);
+
 /**
  * Generic callback for chaining async callbacks
  */
diff --git a/block/curl.c b/block/curl.c
index XXXXXXX..XXXXXXX 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -XXX,XX +XXX,XX @@ static void curl_multi_timeout_do(void *arg)
         return;
     }
 
+    aio_context_acquire(s->aio_context);
     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
 
     curl_multi_check_completion(s);
+    aio_context_release(s->aio_context);
 #else
     abort();
 #endif
diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ void bdrv_aio_cancel(BlockAIOCB *acb)
         if (acb->aiocb_info->get_aio_context) {
             aio_poll(acb->aiocb_info->get_aio_context(acb), true);
         } else if (acb->bs) {
+            /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so
+             * assert that we're not using an I/O thread.  Thread-safe
+             * code should use bdrv_aio_cancel_async exclusively.
+             */
+            assert(bdrv_get_aio_context(acb->bs) == qemu_get_aio_context());
             aio_poll(bdrv_get_aio_context(acb->bs), true);
         } else {
             abort();
diff --git a/block/iscsi.c b/block/iscsi.c
index XXXXXXX..XXXXXXX 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -XXX,XX +XXX,XX @@ static void iscsi_retry_timer_expired(void *opaque)
     struct IscsiTask *iTask = opaque;
     iTask->complete = 1;
     if (iTask->co) {
-        qemu_coroutine_enter(iTask->co);
+        aio_co_wake(iTask->co);
     }
 }
 
@@ -XXX,XX +XXX,XX @@ static void iscsi_nop_timed_event(void *opaque)
 {
     IscsiLun *iscsilun = opaque;
 
+    aio_context_acquire(iscsilun->aio_context);
     if (iscsi_get_nops_in_flight(iscsilun->iscsi) >= MAX_NOP_FAILURES) {
         error_report("iSCSI: NOP timeout. Reconnecting...");
         iscsilun->request_timed_out = true;
     } else if (iscsi_nop_out_async(iscsilun->iscsi, NULL, NULL, 0, NULL) != 0) {
         error_report("iSCSI: failed to sent NOP-Out. Disabling NOP messages.");
-        return;
+        goto out;
     }
 
     timer_mod(iscsilun->nop_timer, qemu_clock_get_ms(QEMU_CLOCK_REALTIME) + NOP_INTERVAL);
     iscsi_set_events(iscsilun);
+
+out:
+    aio_context_release(iscsilun->aio_context);
 }
 
 static void iscsi_readcapacity_sync(IscsiLun *iscsilun, Error **errp)
diff --git a/block/null.c b/block/null.c
index XXXXXXX..XXXXXXX 100644
--- a/block/null.c
+++ b/block/null.c
@@ -XXX,XX +XXX,XX @@ static void null_bh_cb(void *opaque)
 static void null_timer_cb(void *opaque)
 {
     NullAIOCB *acb = opaque;
+    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
+
+    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, 0);
+    aio_context_release(ctx);
     timer_deinit(&acb->timer);
     qemu_aio_unref(acb);
 }
diff --git a/block/qed.c b/block/qed.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -XXX,XX +XXX,XX @@ static void qed_need_check_timer_cb(void *opaque)
 
     trace_qed_need_check_timer_cb(s);
 
+    qed_acquire(s);
     qed_plug_allocating_write_reqs(s);
 
     /* Ensure writes are on disk before clearing flag */
     bdrv_aio_flush(s->bs->file->bs, qed_clear_need_check, s);
+    qed_release(s);
+}
+
+void qed_acquire(BDRVQEDState *s)
+{
+    aio_context_acquire(bdrv_get_aio_context(s->bs));
+}
+
+void qed_release(BDRVQEDState *s)
+{
+    aio_context_release(bdrv_get_aio_context(s->bs));
 }
 
 static void qed_start_need_check_timer(BDRVQEDState *s)
diff --git a/block/throttle-groups.c b/block/throttle-groups.c
index XXXXXXX..XXXXXXX 100644
--- a/block/throttle-groups.c
+++ b/block/throttle-groups.c
@@ -XXX,XX +XXX,XX @@ static void timer_cb(BlockBackend *blk, bool is_write)
     qemu_mutex_unlock(&tg->lock);
 
     /* Run the request that was waiting for this timer */
+    aio_context_acquire(blk_get_aio_context(blk));
     empty_queue = !qemu_co_enter_next(&blkp->throttled_reqs[is_write]);
+    aio_context_release(blk_get_aio_context(blk));
 
     /* If the request queue was empty then we have to take care of
      * scheduling the next one */
diff --git a/util/aio-posix.c b/util/aio-posix.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -XXX,XX +XXX,XX @@ bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
     }
 
     /* Run our timers */
-    aio_context_acquire(ctx);
     progress |= timerlistgroup_run_timers(&ctx->tlg);
-    aio_context_release(ctx);
 
     return progress;
 }
diff --git a/util/aio-win32.c b/util/aio-win32.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-win32.c
+++ b/util/aio-win32.c
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
         progress |= aio_dispatch_handlers(ctx, event);
     } while (count > 0);
 
-    aio_context_acquire(ctx);
     progress |= timerlistgroup_run_timers(&ctx->tlg);
-    aio_context_release(ctx);
     return progress;
 }
 
diff --git a/util/qemu-coroutine-sleep.c b/util/qemu-coroutine-sleep.c
index XXXXXXX..XXXXXXX 100644
--- a/util/qemu-coroutine-sleep.c
+++ b/util/qemu-coroutine-sleep.c
@@ -XXX,XX +XXX,XX @@ static void co_sleep_cb(void *opaque)
 {
     CoSleepCB *sleep_cb = opaque;
 
-    qemu_coroutine_enter(sleep_cb->co);
+    aio_co_wake(sleep_cb->co);
 }
 
 void coroutine_fn co_aio_sleep_ns(AioContext *ctx, QEMUClockType type,
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

This covers both file descriptor callbacks and polling callbacks,
since they execute related code.

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-14-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/curl.c          | 16 +++++++++++++---
 block/iscsi.c         |  4 ++++
 block/linux-aio.c     |  4 ++++
 block/nfs.c           |  6 ++++++
 block/sheepdog.c      | 29 +++++++++++++++--------------
 block/ssh.c           | 29 +++++++++--------------------
 block/win32-aio.c     | 10 ++++++----
 hw/block/virtio-blk.c |  5 ++++-
 hw/scsi/virtio-scsi.c |  7 +++++++
 util/aio-posix.c      |  7 -------
 util/aio-win32.c      |  6 ------
 11 files changed, 68 insertions(+), 55 deletions(-)

diff --git a/block/curl.c b/block/curl.c
index XXXXXXX..XXXXXXX 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -XXX,XX +XXX,XX @@ static void curl_multi_check_completion(BDRVCURLState *s)
     }
 }
 
-static void curl_multi_do(void *arg)
+static void curl_multi_do_locked(CURLState *s)
 {
-    CURLState *s = (CURLState *)arg;
     CURLSocket *socket, *next_socket;
     int running;
     int r;
@@ -XXX,XX +XXX,XX @@ static void curl_multi_do(void *arg)
     }
 }
 
+static void curl_multi_do(void *arg)
+{
+    CURLState *s = (CURLState *)arg;
+
+    aio_context_acquire(s->s->aio_context);
+    curl_multi_do_locked(s);
+    aio_context_release(s->s->aio_context);
+}
+
 static void curl_multi_read(void *arg)
 {
     CURLState *s = (CURLState *)arg;
 
-    curl_multi_do(arg);
+    aio_context_acquire(s->s->aio_context);
+    curl_multi_do_locked(s);
     curl_multi_check_completion(s->s);
+    aio_context_release(s->s->aio_context);
 }
 
 static void curl_multi_timeout_do(void *arg)
diff --git a/block/iscsi.c b/block/iscsi.c
index XXXXXXX..XXXXXXX 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -XXX,XX +XXX,XX @@ iscsi_process_read(void *arg)
     IscsiLun *iscsilun = arg;
     struct iscsi_context *iscsi = iscsilun->iscsi;
 
+    aio_context_acquire(iscsilun->aio_context);
     iscsi_service(iscsi, POLLIN);
     iscsi_set_events(iscsilun);
+    aio_context_release(iscsilun->aio_context);
 }
 
 static void
@@ -XXX,XX +XXX,XX @@ iscsi_process_write(void *arg)
     IscsiLun *iscsilun = arg;
     struct iscsi_context *iscsi = iscsilun->iscsi;
 
+    aio_context_acquire(iscsilun->aio_context);
     iscsi_service(iscsi, POLLOUT);
     iscsi_set_events(iscsilun);
+    aio_context_release(iscsilun->aio_context);
 }
 
 static int64_t sector_lun2qemu(int64_t sector, IscsiLun *iscsilun)
diff --git a/block/linux-aio.c b/block/linux-aio.c
index XXXXXXX..XXXXXXX 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_completion_cb(EventNotifier *e)
     LinuxAioState *s = container_of(e, LinuxAioState, e);
 
     if (event_notifier_test_and_clear(&s->e)) {
+        aio_context_acquire(s->aio_context);
         qemu_laio_process_completions_and_submit(s);
+        aio_context_release(s->aio_context);
     }
 }
 
@@ -XXX,XX +XXX,XX @@ static bool qemu_laio_poll_cb(void *opaque)
         return false;
     }
 
+    aio_context_acquire(s->aio_context);
     qemu_laio_process_completions_and_submit(s);
+    aio_context_release(s->aio_context);
     return true;
 }
 
diff --git a/block/nfs.c b/block/nfs.c
index XXXXXXX..XXXXXXX 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -XXX,XX +XXX,XX @@ static void nfs_set_events(NFSClient *client)
 static void nfs_process_read(void *arg)
 {
     NFSClient *client = arg;
+
+    aio_context_acquire(client->aio_context);
     nfs_service(client->context, POLLIN);
     nfs_set_events(client);
+    aio_context_release(client->aio_context);
 }
 
 static void nfs_process_write(void *arg)
 {
     NFSClient *client = arg;
+
+    aio_context_acquire(client->aio_context);
     nfs_service(client->context, POLLOUT);
     nfs_set_events(client);
+    aio_context_release(client->aio_context);
 }
 
 static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
diff --git a/block/sheepdog.c b/block/sheepdog.c
index XXXXXXX..XXXXXXX 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -XXX,XX +XXX,XX @@ static coroutine_fn int send_co_req(int sockfd, SheepdogReq *hdr, void *data,
     return ret;
 }
 
-static void restart_co_req(void *opaque)
-{
-    Coroutine *co = opaque;
-
-    qemu_coroutine_enter(co);
-}
-
 typedef struct SheepdogReqCo {
     int sockfd;
     BlockDriverState *bs;
@@ -XXX,XX +XXX,XX @@ typedef struct SheepdogReqCo {
     unsigned int *rlen;
     int ret;
     bool finished;
+    Coroutine *co;
 } SheepdogReqCo;
 
+static void restart_co_req(void *opaque)
+{
+    SheepdogReqCo *srco = opaque;
+
+    aio_co_wake(srco->co);
+}
+
 static coroutine_fn void do_co_req(void *opaque)
 {
     int ret;
-    Coroutine *co;
     SheepdogReqCo *srco = opaque;
     int sockfd = srco->sockfd;
     SheepdogReq *hdr = srco->hdr;
@@ -XXX,XX +XXX,XX @@ static coroutine_fn void do_co_req(void *opaque)
     unsigned int *wlen = srco->wlen;
     unsigned int *rlen = srco->rlen;
 
-    co = qemu_coroutine_self();
+    srco->co = qemu_coroutine_self();
     aio_set_fd_handler(srco->aio_context, sockfd, false,
-                       NULL, restart_co_req, NULL, co);
+                       NULL, restart_co_req, NULL, srco);
 
     ret = send_co_req(sockfd, hdr, data, wlen);
     if (ret < 0) {
@@ -XXX,XX +XXX,XX @@ static coroutine_fn void do_co_req(void *opaque)
     }
 
     aio_set_fd_handler(srco->aio_context, sockfd, false,
-                       restart_co_req, NULL, NULL, co);
+                       restart_co_req, NULL, NULL, srco);
 
     ret = qemu_co_recv(sockfd, hdr, sizeof(*hdr));
     if (ret != sizeof(*hdr)) {
@@ -XXX,XX +XXX,XX @@ out:
     aio_set_fd_handler(srco->aio_context, sockfd, false,
                        NULL, NULL, NULL, NULL);
 
+    srco->co = NULL;
     srco->ret = ret;
     srco->finished = true;
     if (srco->bs) {
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn aio_read_response(void *opaque)
          * We've finished all requests which belong to the AIOCB, so
          * we can switch back to sd_co_readv/writev now.
          */
-        qemu_coroutine_enter(acb->coroutine);
+        aio_co_wake(acb->coroutine);
     }
 
     return;
@@ -XXX,XX +XXX,XX @@ static void co_read_response(void *opaque)
         s->co_recv = qemu_coroutine_create(aio_read_response, opaque);
     }
 
-    qemu_coroutine_enter(s->co_recv);
+    aio_co_wake(s->co_recv);
 }
 
 static void co_write_request(void *opaque)
 {
     BDRVSheepdogState *s = opaque;
 
-    qemu_coroutine_enter(s->co_send);
+    aio_co_wake(s->co_send);
 }
 
 /*
diff --git a/block/ssh.c b/block/ssh.c
index XXXXXXX..XXXXXXX 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -XXX,XX +XXX,XX @@ static void restart_coroutine(void *opaque)
 
     DPRINTF("co=%p", co);
 
-    qemu_coroutine_enter(co);
+    aio_co_wake(co);
 }
 
-static coroutine_fn void set_fd_handler(BDRVSSHState *s, BlockDriverState *bs)
+/* A non-blocking call returned EAGAIN, so yield, ensuring the
+ * handlers are set up so that we'll be rescheduled when there is an
+ * interesting event on the socket.
+ */
+static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
 {
     int r;
     IOHandler *rd_handler = NULL, *wr_handler = NULL;
@@ -XXX,XX +XXX,XX @@ static coroutine_fn void set_fd_handler(BDRVSSHState *s, BlockDriverState *bs)
 
     aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
                        false, rd_handler, wr_handler, NULL, co);
-}
-
-static coroutine_fn void clear_fd_handler(BDRVSSHState *s,
-                                          BlockDriverState *bs)
-{
-    DPRINTF("s->sock=%d", s->sock);
-    aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock,
-                       false, NULL, NULL, NULL, NULL);
-}
-
-/* A non-blocking call returned EAGAIN, so yield, ensuring the
- * handlers are set up so that we'll be rescheduled when there is an
- * interesting event on the socket.
- */
-static coroutine_fn void co_yield(BDRVSSHState *s, BlockDriverState *bs)
-{
-    set_fd_handler(s, bs);
     qemu_coroutine_yield();
-    clear_fd_handler(s, bs);
+    DPRINTF("s->sock=%d - back", s->sock);
+    aio_set_fd_handler(bdrv_get_aio_context(bs), s->sock, false,
+                       NULL, NULL, NULL, NULL);
 }
 
 /* SFTP has a function `libssh2_sftp_seek64' which seeks to a position
diff --git a/block/win32-aio.c b/block/win32-aio.c
index XXXXXXX..XXXXXXX 100644
--- a/block/win32-aio.c
+++ b/block/win32-aio.c
@@ -XXX,XX +XXX,XX @@ struct QEMUWin32AIOState {
     HANDLE hIOCP;
     EventNotifier e;
     int count;
-    bool is_aio_context_attached;
+    AioContext *aio_ctx;
 };
 
 typedef struct QEMUWin32AIOCB {
@@ -XXX,XX +XXX,XX @@ static void win32_aio_process_completion(QEMUWin32AIOState *s,
     }
 
 
+    aio_context_acquire(s->aio_ctx);
     waiocb->common.cb(waiocb->common.opaque, ret);
+    aio_context_release(s->aio_ctx);
     qemu_aio_unref(waiocb);
 }
 
@@ -XXX,XX +XXX,XX @@ void win32_aio_detach_aio_context(QEMUWin32AIOState *aio,
                                   AioContext *old_context)
 {
     aio_set_event_notifier(old_context, &aio->e, false, NULL, NULL);
-    aio->is_aio_context_attached = false;
+    aio->aio_ctx = NULL;
 }
 
 void win32_aio_attach_aio_context(QEMUWin32AIOState *aio,
                                   AioContext *new_context)
 {
-    aio->is_aio_context_attached = true;
+    aio->aio_ctx = new_context;
     aio_set_event_notifier(new_context, &aio->e, false,
                            win32_aio_completion_cb, NULL);
 }
@@ -XXX,XX +XXX,XX @@ out_free_state:
 
 void win32_aio_cleanup(QEMUWin32AIOState *aio)
 {
-    assert(!aio->is_aio_context_attached);
+    assert(!aio->aio_ctx);
     CloseHandle(aio->hIOCP);
     event_notifier_cleanup(&aio->e);
     g_free(aio);
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -XXX,XX +XXX,XX @@ static void virtio_blk_ioctl_complete(void *opaque, int status)
 {
     VirtIOBlockIoctlReq *ioctl_req = opaque;
     VirtIOBlockReq *req = ioctl_req->req;
-    VirtIODevice *vdev = VIRTIO_DEVICE(req->dev);
+    VirtIOBlock *s = req->dev;
+    VirtIODevice *vdev = VIRTIO_DEVICE(s);
     struct virtio_scsi_inhdr *scsi;
     struct sg_io_hdr *hdr;
 
@@ -XXX,XX +XXX,XX @@ bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
     MultiReqBuffer mrb = {};
     bool progress = false;
 
+    aio_context_acquire(blk_get_aio_context(s->blk));
     blk_io_plug(s->blk);
 
     do {
@@ -XXX,XX +XXX,XX @@ bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq)
     }
 
     blk_io_unplug(s->blk);
+    aio_context_release(blk_get_aio_context(s->blk));
     return progress;
 }
 
diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/scsi/virtio-scsi.c
+++ b/hw/scsi/virtio-scsi.c
@@ -XXX,XX +XXX,XX @@ bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
     VirtIOSCSIReq *req;
     bool progress = false;
 
+    virtio_scsi_acquire(s);
     while ((req = virtio_scsi_pop_req(s, vq))) {
         progress = true;
         virtio_scsi_handle_ctrl_req(s, req);
     }
+    virtio_scsi_release(s);
     return progress;
 }
 
@@ -XXX,XX +XXX,XX @@ bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
 
     QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
 
+    virtio_scsi_acquire(s);
     do {
         virtio_queue_set_notification(vq, 0);
 
@@ -XXX,XX +XXX,XX @@ bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
     QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
         virtio_scsi_handle_cmd_req_submit(s, req);
     }
+    virtio_scsi_release(s);
     return progress;
 }
 
@@ -XXX,XX +XXX,XX @@ out:
 
 bool virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
 {
+    virtio_scsi_acquire(s);
     if (s->events_dropped) {
         virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
+        virtio_scsi_release(s);
         return true;
     }
+    virtio_scsi_release(s);
     return false;
 }
 
diff --git a/util/aio-posix.c b/util/aio-posix.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
             (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) &&
             aio_node_check(ctx, node->is_external) &&
             node->io_read) {
-            aio_context_acquire(ctx);
             node->io_read(node->opaque);
-            aio_context_release(ctx);
 
             /* aio_notify() does not count as progress */
             if (node->opaque != &ctx->notifier) {
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
             (revents & (G_IO_OUT | G_IO_ERR)) &&
             aio_node_check(ctx, node->is_external) &&
             node->io_write) {
-            aio_context_acquire(ctx);
             node->io_write(node->opaque);
-            aio_context_release(ctx);
             progress = true;
         }
 
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
         start = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
     }
 
-    aio_context_acquire(ctx);
     progress = try_poll_mode(ctx, blocking);
-    aio_context_release(ctx);
-
     if (!progress) {
         assert(npfd == 0);
 
diff --git a/util/aio-win32.c b/util/aio-win32.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-win32.c
+++ b/util/aio-win32.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
             (revents || event_notifier_get_handle(node->e) == event) &&
             node->io_notify) {
             node->pfd.revents = 0;
-            aio_context_acquire(ctx);
             node->io_notify(node->e);
-            aio_context_release(ctx);
 
             /* aio_notify() does not count as progress */
             if (node->e != &ctx->notifier) {
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
             (node->io_read || node->io_write)) {
             node->pfd.revents = 0;
             if ((revents & G_IO_IN) && node->io_read) {
-                aio_context_acquire(ctx);
                 node->io_read(node->opaque);
-                aio_context_release(ctx);
                 progress = true;
             }
             if ((revents & G_IO_OUT) && node->io_write) {
-                aio_context_acquire(ctx);
                 node->io_write(node->opaque);
-                aio_context_release(ctx);
                 progress = true;
             }
 
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-15-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/archipelago.c   |  3 +++
 block/blkreplay.c     |  2 +-
 block/block-backend.c |  6 ++++++
 block/curl.c          | 26 ++++++++++++++++++--------
 block/gluster.c       |  9 +--------
 block/io.c            |  6 +++++-
 block/iscsi.c         |  6 +++++-
 block/linux-aio.c     | 15 +++++++++------
 block/nfs.c           |  3 ++-
 block/null.c          |  4 ++++
 block/qed.c           |  3 +++
 block/rbd.c           |  4 ++++
 dma-helpers.c         |  2 ++
 hw/block/virtio-blk.c |  2 ++
 hw/scsi/scsi-bus.c    |  2 ++
 util/async.c          |  4 ++--
 util/thread-pool.c    |  2 ++
 17 files changed, 71 insertions(+), 28 deletions(-)

diff --git a/block/archipelago.c b/block/archipelago.c
index XXXXXXX..XXXXXXX 100644
--- a/block/archipelago.c
+++ b/block/archipelago.c
@@ -XXX,XX +XXX,XX @@ static void qemu_archipelago_complete_aio(void *opaque)
 {
     AIORequestData *reqdata = (AIORequestData *) opaque;
     ArchipelagoAIOCB *aio_cb = (ArchipelagoAIOCB *) reqdata->aio_cb;
+    AioContext *ctx = bdrv_get_aio_context(aio_cb->common.bs);
 
+    aio_context_acquire(ctx);
     aio_cb->common.cb(aio_cb->common.opaque, aio_cb->ret);
+    aio_context_release(ctx);
     aio_cb->status = 0;
 
     qemu_aio_unref(aio_cb);
diff --git a/block/blkreplay.c b/block/blkreplay.c
index XXXXXXX..XXXXXXX 100755
--- a/block/blkreplay.c
+++ b/block/blkreplay.c
@@ -XXX,XX +XXX,XX @@ static int64_t blkreplay_getlength(BlockDriverState *bs)
 static void blkreplay_bh_cb(void *opaque)
 {
     Request *req = opaque;
-    qemu_coroutine_enter(req->co);
+    aio_co_wake(req->co);
     qemu_bh_delete(req->bh);
     g_free(req);
 }
diff --git a/block/block-backend.c b/block/block-backend.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -XXX,XX +XXX,XX @@ int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags)
 static void error_callback_bh(void *opaque)
 {
     struct BlockBackendAIOCB *acb = opaque;
+    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
 
     bdrv_dec_in_flight(acb->common.bs);
+    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, acb->ret);
+    aio_context_release(ctx);
     qemu_aio_unref(acb);
 }
 
@@ -XXX,XX +XXX,XX @@ static void blk_aio_complete(BlkAioEmAIOCB *acb)
 static void blk_aio_complete_bh(void *opaque)
 {
     BlkAioEmAIOCB *acb = opaque;
+    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
 
     assert(acb->has_returned);
+    aio_context_acquire(ctx);
     blk_aio_complete(acb);
+    aio_context_release(ctx);
 }
 
 static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes,
diff --git a/block/curl.c b/block/curl.c
index XXXXXXX..XXXXXXX 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
 {
     CURLState *state;
     int running;
+    int ret = -EINPROGRESS;
 
     CURLAIOCB *acb = p;
-    BDRVCURLState *s = acb->common.bs->opaque;
+    BlockDriverState *bs = acb->common.bs;
+    BDRVCURLState *s = bs->opaque;
+    AioContext *ctx = bdrv_get_aio_context(bs);
 
     size_t start = acb->sector_num * BDRV_SECTOR_SIZE;
     size_t end;
 
+    aio_context_acquire(ctx);
+
     // In case we have the requested data already (e.g. read-ahead),
     // we can just call the callback and be done.
     switch (curl_find_buf(s, start, acb->nb_sectors * BDRV_SECTOR_SIZE, acb)) {
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
             qemu_aio_unref(acb);
             // fall through
         case FIND_RET_WAIT:
-            return;
+            goto out;
         default:
             break;
     }
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
     // No cache found, so let's start a new request
     state = curl_init_state(acb->common.bs, s);
     if (!state) {
-        acb->common.cb(acb->common.opaque, -EIO);
-        qemu_aio_unref(acb);
-        return;
+        ret = -EIO;
+        goto out;
     }
 
     acb->start = 0;
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
     state->orig_buf = g_try_malloc(state->buf_len);
     if (state->buf_len && state->orig_buf == NULL) {
         curl_clean_state(state);
-        acb->common.cb(acb->common.opaque, -ENOMEM);
-        qemu_aio_unref(acb);
-        return;
+        ret = -ENOMEM;
+        goto out;
     }
     state->acb[0] = acb;
 
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
 
     /* Tell curl it needs to kick things off */
     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
+
+out:
+    if (ret != -EINPROGRESS) {
+        acb->common.cb(acb->common.opaque, ret);
+        qemu_aio_unref(acb);
+    }
+    aio_context_release(ctx);
 }
 
 static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,
diff --git a/block/gluster.c b/block/gluster.c
index XXXXXXX..XXXXXXX 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -XXX,XX +XXX,XX @@ static struct glfs *qemu_gluster_init(BlockdevOptionsGluster *gconf,
     return qemu_gluster_glfs_init(gconf, errp);
 }
 
-static void qemu_gluster_complete_aio(void *opaque)
-{
-    GlusterAIOCB *acb = (GlusterAIOCB *)opaque;
-
-    qemu_coroutine_enter(acb->coroutine);
-}
-
 /*
  * AIO callback routine called from GlusterFS thread.
  */
@@ -XXX,XX +XXX,XX @@ static void gluster_finish_aiocb(struct glfs_fd *fd, ssize_t ret, void *arg)
         acb->ret = -EIO; /* Partial read/write - fail it */
     }
 
-    aio_bh_schedule_oneshot(acb->aio_context, qemu_gluster_complete_aio, acb);
+    aio_co_schedule(acb->aio_context, acb->coroutine);
 }
 
 static void qemu_gluster_parse_flags(int bdrv_flags, int *open_flags)
diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ static void bdrv_co_drain_bh_cb(void *opaque)
     bdrv_dec_in_flight(bs);
     bdrv_drained_begin(bs);
     data->done = true;
-    qemu_coroutine_enter(co);
+    aio_co_wake(co);
 }
 
 static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs)
@@ -XXX,XX +XXX,XX @@ static void bdrv_co_complete(BlockAIOCBCoroutine *acb)
 static void bdrv_co_em_bh(void *opaque)
 {
     BlockAIOCBCoroutine *acb = opaque;
+    BlockDriverState *bs = acb->common.bs;
+    AioContext *ctx = bdrv_get_aio_context(bs);
 
     assert(!acb->need_bh);
+    aio_context_acquire(ctx);
     bdrv_co_complete(acb);
+    aio_context_release(ctx);
 }
 
 static void bdrv_co_maybe_schedule_bh(BlockAIOCBCoroutine *acb)
diff --git a/block/iscsi.c b/block/iscsi.c
index XXXXXXX..XXXXXXX 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -XXX,XX +XXX,XX @@ static void
 iscsi_bh_cb(void *p)
 {
     IscsiAIOCB *acb = p;
+    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
 
     qemu_bh_delete(acb->bh);
 
     g_free(acb->buf);
     acb->buf = NULL;
 
+    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, acb->status);
+    aio_context_release(ctx);
 
     if (acb->task != NULL) {
         scsi_free_scsi_task(acb->task);
@@ -XXX,XX +XXX,XX @@ iscsi_schedule_bh(IscsiAIOCB *acb)
 static void iscsi_co_generic_bh_cb(void *opaque)
 {
     struct IscsiTask *iTask = opaque;
+
     iTask->complete = 1;
-    qemu_coroutine_enter(iTask->co);
+    aio_co_wake(iTask->co);
 }
 
 static void iscsi_retry_timer_expired(void *opaque)
diff --git a/block/linux-aio.c b/block/linux-aio.c
index XXXXXXX..XXXXXXX 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -XXX,XX +XXX,XX @@ struct LinuxAioState {
     io_context_t ctx;
     EventNotifier e;
 
-    /* io queue for submit at batch */
+    /* io queue for submit at batch.  Protected by AioContext lock. */
     LaioQueue io_q;
 
-    /* I/O completion processing */
+    /* I/O completion processing.  Only runs in I/O thread.  */
     QEMUBH *completion_bh;
     int event_idx;
     int event_max;
@@ -XXX,XX +XXX,XX @@ static inline ssize_t io_event_ret(struct io_event *ev)
  */
 static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
 {
+    LinuxAioState *s = laiocb->ctx;
     int ret;
 
     ret = laiocb->ret;
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
     }
 
     laiocb->ret = ret;
+    aio_context_acquire(s->aio_context);
     if (laiocb->co) {
         /* If the coroutine is already entered it must be in ioq_submit() and
          * will notice laio->ret has been filled in when it eventually runs
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
         laiocb->common.cb(laiocb->common.opaque, ret);
         qemu_aio_unref(laiocb);
     }
+    aio_context_release(s->aio_context);
 }
 
 /**
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completions(LinuxAioState *s)
 static void qemu_laio_process_completions_and_submit(LinuxAioState *s)
 {
     qemu_laio_process_completions(s);
+
+    aio_context_acquire(s->aio_context);
     if (!s->io_q.plugged && !QSIMPLEQ_EMPTY(&s->io_q.pending)) {
         ioq_submit(s);
     }
+    aio_context_release(s->aio_context);
 }
 
 static void qemu_laio_completion_bh(void *opaque)
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_completion_cb(EventNotifier *e)
     LinuxAioState *s = container_of(e, LinuxAioState, e);
 
     if (event_notifier_test_and_clear(&s->e)) {
-        aio_context_acquire(s->aio_context);
         qemu_laio_process_completions_and_submit(s);
-        aio_context_release(s->aio_context);
     }
 }
 
@@ -XXX,XX +XXX,XX @@ static bool qemu_laio_poll_cb(void *opaque)
         return false;
     }
 
-    aio_context_acquire(s->aio_context);
     qemu_laio_process_completions_and_submit(s);
-    aio_context_release(s->aio_context);
     return true;
 }
 
@@ -XXX,XX +XXX,XX @@ void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context)
 {
     aio_set_event_notifier(old_context, &s->e, false, NULL, NULL);
     qemu_bh_delete(s->completion_bh);
+    s->aio_context = NULL;
 }
 
 void laio_attach_aio_context(LinuxAioState *s, AioContext *new_context)
diff --git a/block/nfs.c b/block/nfs.c
index XXXXXXX..XXXXXXX 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -XXX,XX +XXX,XX @@ static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
 static void nfs_co_generic_bh_cb(void *opaque)
 {
     NFSRPC *task = opaque;
+
     task->complete = 1;
-    qemu_coroutine_enter(task->co);
+    aio_co_wake(task->co);
 }
 
 static void
diff --git a/block/null.c b/block/null.c
index XXXXXXX..XXXXXXX 100644
--- a/block/null.c
+++ b/block/null.c
@@ -XXX,XX +XXX,XX @@ static const AIOCBInfo null_aiocb_info = {
 static void null_bh_cb(void *opaque)
 {
     NullAIOCB *acb = opaque;
+    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
+
+    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, 0);
+    aio_context_release(ctx);
     qemu_aio_unref(acb);
 }
 
diff --git a/block/qed.c b/block/qed.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -XXX,XX +XXX,XX @@ static void qed_update_l2_table(BDRVQEDState *s, QEDTable *table, int index,
 static void qed_aio_complete_bh(void *opaque)
 {
     QEDAIOCB *acb = opaque;
+    BDRVQEDState *s = acb_to_s(acb);
     BlockCompletionFunc *cb = acb->common.cb;
     void *user_opaque = acb->common.opaque;
     int ret = acb->bh_ret;
@@ -XXX,XX +XXX,XX @@ static void qed_aio_complete_bh(void *opaque)
     qemu_aio_unref(acb);
 
     /* Invoke callback */
+    qed_acquire(s);
     cb(user_opaque, ret);
+    qed_release(s);
 }
 
 static void qed_aio_complete(QEDAIOCB *acb, int ret)
diff --git a/block/rbd.c b/block/rbd.c
index XXXXXXX..XXXXXXX 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -XXX,XX +XXX,XX @@ shutdown:
 static void qemu_rbd_complete_aio(RADOSCB *rcb)
 {
     RBDAIOCB *acb = rcb->acb;
+    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
     int64_t r;
 
     r = rcb->ret;
@@ -XXX,XX +XXX,XX @@ static void qemu_rbd_complete_aio(RADOSCB *rcb)
         qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
     }
     qemu_vfree(acb->bounce);
+
+    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
+    aio_context_release(ctx);
 
     qemu_aio_unref(acb);
 }
diff --git a/dma-helpers.c b/dma-helpers.c
index XXXXXXX..XXXXXXX 100644
--- a/dma-helpers.c
+++ b/dma-helpers.c
@@ -XXX,XX +XXX,XX @@ static void dma_blk_cb(void *opaque, int ret)
                                 QEMU_ALIGN_DOWN(dbs->iov.size, dbs->align));
     }
 
+    aio_context_acquire(dbs->ctx);
     dbs->acb = dbs->io_func(dbs->offset, &dbs->iov,
                             dma_blk_cb, dbs, dbs->io_func_opaque);
+    aio_context_release(dbs->ctx);
     assert(dbs->acb);
 }
 
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -XXX,XX +XXX,XX @@ static void virtio_blk_dma_restart_bh(void *opaque)
 
     s->rq = NULL;
 
+    aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
     while (req) {
         VirtIOBlockReq *next = req->next;
         if (virtio_blk_handle_request(req, &mrb)) {
@@ -XXX,XX +XXX,XX @@ static void virtio_blk_dma_restart_bh(void *opaque)
     if (mrb.num_reqs) {
         virtio_blk_submit_multireq(s->blk, &mrb);
     }
+    aio_context_release(blk_get_aio_context(s->conf.conf.blk));
 }
 
 static void virtio_blk_dma_restart_cb(void *opaque, int running,
diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/scsi/scsi-bus.c
+++ b/hw/scsi/scsi-bus.c
@@ -XXX,XX +XXX,XX @@ static void scsi_dma_restart_bh(void *opaque)
     qemu_bh_delete(s->bh);
     s->bh = NULL;
 
+    aio_context_acquire(blk_get_aio_context(s->conf.blk));
     QTAILQ_FOREACH_SAFE(req, &s->requests, next, next) {
         scsi_req_ref(req);
         if (req->retry) {
@@ -XXX,XX +XXX,XX @@ static void scsi_dma_restart_bh(void *opaque)
         }
         scsi_req_unref(req);
     }
+    aio_context_release(blk_get_aio_context(s->conf.blk));
 }
 
 void scsi_req_retry(SCSIRequest *req)
diff --git a/util/async.c b/util/async.c
index XXXXXXX..XXXXXXX 100644
--- a/util/async.c
+++ b/util/async.c
@@ -XXX,XX +XXX,XX @@ int aio_bh_poll(AioContext *ctx)
                 ret = 1;
             }
             bh->idle = 0;
-            aio_context_acquire(ctx);
             aio_bh_call(bh);
-            aio_context_release(ctx);
         }
         if (bh->deleted) {
             deleted = true;
@@ -XXX,XX +XXX,XX @@ static void co_schedule_bh_cb(void *opaque)
         Coroutine *co = QSLIST_FIRST(&straight);
         QSLIST_REMOVE_HEAD(&straight, co_scheduled_next);
         trace_aio_co_schedule_bh_cb(ctx, co);
+        aio_context_acquire(ctx);
         qemu_coroutine_enter(co);
+        aio_context_release(ctx);
     }
 }
 
diff --git a/util/thread-pool.c b/util/thread-pool.c
index XXXXXXX..XXXXXXX 100644
--- a/util/thread-pool.c
+++ b/util/thread-pool.c
@@ -XXX,XX +XXX,XX @@ static void thread_pool_completion_bh(void *opaque)
     ThreadPool *pool = opaque;
     ThreadPoolElement *elem, *next;
 
+    aio_context_acquire(pool->ctx);
 restart:
     QLIST_FOREACH_SAFE(elem, &pool->head, all, next) {
         if (elem->state != THREAD_DONE) {
@@ -XXX,XX +XXX,XX @@ restart:
             qemu_aio_unref(elem);
         }
     }
+    aio_context_release(pool->ctx);
 }
 
 static void thread_pool_cancel(BlockAIOCB *acb)
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-16-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/archipelago.c    |  3 ---
 block/block-backend.c  |  7 -------
 block/curl.c           |  2 +-
 block/io.c             |  6 +-----
 block/iscsi.c          |  3 ---
 block/linux-aio.c      |  5 +----
 block/mirror.c         | 12 +++++++++---
 block/null.c           |  8 --------
 block/qed-cluster.c    |  2 ++
 block/qed-table.c      | 12 ++++++++++--
 block/qed.c            |  4 ++--
 block/rbd.c            |  4 ----
 block/win32-aio.c      |  3 ---
 hw/block/virtio-blk.c  | 12 +++++++++++-
 hw/scsi/scsi-disk.c    | 15 +++++++++++++++
 hw/scsi/scsi-generic.c | 20 +++++++++++++++++---
 util/thread-pool.c     |  4 +++-
 17 files changed, 72 insertions(+), 50 deletions(-)

diff --git a/block/archipelago.c b/block/archipelago.c
index XXXXXXX..XXXXXXX 100644
--- a/block/archipelago.c
+++ b/block/archipelago.c
@@ -XXX,XX +XXX,XX @@ static void qemu_archipelago_complete_aio(void *opaque)
 {
     AIORequestData *reqdata = (AIORequestData *) opaque;
     ArchipelagoAIOCB *aio_cb = (ArchipelagoAIOCB *) reqdata->aio_cb;
-    AioContext *ctx = bdrv_get_aio_context(aio_cb->common.bs);
 
-    aio_context_acquire(ctx);
     aio_cb->common.cb(aio_cb->common.opaque, aio_cb->ret);
-    aio_context_release(ctx);
     aio_cb->status = 0;
 
     qemu_aio_unref(aio_cb);
diff --git a/block/block-backend.c b/block/block-backend.c
index XXXXXXX..XXXXXXX 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -XXX,XX +XXX,XX @@ int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags)
 static void error_callback_bh(void *opaque)
 {
     struct BlockBackendAIOCB *acb = opaque;
-    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
 
     bdrv_dec_in_flight(acb->common.bs);
-    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, acb->ret);
-    aio_context_release(ctx);
     qemu_aio_unref(acb);
 }
 
@@ -XXX,XX +XXX,XX @@ static void blk_aio_complete(BlkAioEmAIOCB *acb)
 static void blk_aio_complete_bh(void *opaque)
 {
     BlkAioEmAIOCB *acb = opaque;
-    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
-
     assert(acb->has_returned);
-    aio_context_acquire(ctx);
     blk_aio_complete(acb);
-    aio_context_release(ctx);
 }
 
 static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes,
diff --git a/block/curl.c b/block/curl.c
index XXXXXXX..XXXXXXX 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -XXX,XX +XXX,XX @@ static void curl_readv_bh_cb(void *p)
     curl_multi_socket_action(s->multi, CURL_SOCKET_TIMEOUT, 0, &running);
 
 out:
+    aio_context_release(ctx);
     if (ret != -EINPROGRESS) {
         acb->common.cb(acb->common.opaque, ret);
         qemu_aio_unref(acb);
     }
-    aio_context_release(ctx);
 }
 
 static BlockAIOCB *curl_aio_readv(BlockDriverState *bs,
diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ static void bdrv_co_io_em_complete(void *opaque, int ret)
     CoroutineIOCompletion *co = opaque;
 
     co->ret = ret;
-    qemu_coroutine_enter(co->coroutine);
+    aio_co_wake(co->coroutine);
 }
 
 static int coroutine_fn bdrv_driver_preadv(BlockDriverState *bs,
@@ -XXX,XX +XXX,XX @@ static void bdrv_co_complete(BlockAIOCBCoroutine *acb)
 static void bdrv_co_em_bh(void *opaque)
 {
     BlockAIOCBCoroutine *acb = opaque;
-    BlockDriverState *bs = acb->common.bs;
-    AioContext *ctx = bdrv_get_aio_context(bs);
 
     assert(!acb->need_bh);
-    aio_context_acquire(ctx);
     bdrv_co_complete(acb);
-    aio_context_release(ctx);
 }
 
 static void bdrv_co_maybe_schedule_bh(BlockAIOCBCoroutine *acb)
diff --git a/block/iscsi.c b/block/iscsi.c
index XXXXXXX..XXXXXXX 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -XXX,XX +XXX,XX @@ static void
 iscsi_bh_cb(void *p)
 {
     IscsiAIOCB *acb = p;
-    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
 
     qemu_bh_delete(acb->bh);
 
     g_free(acb->buf);
     acb->buf = NULL;
 
-    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, acb->status);
-    aio_context_release(ctx);
 
     if (acb->task != NULL) {
         scsi_free_scsi_task(acb->task);
diff --git a/block/linux-aio.c b/block/linux-aio.c
index XXXXXXX..XXXXXXX 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -XXX,XX +XXX,XX @@ static inline ssize_t io_event_ret(struct io_event *ev)
  */
 static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
 {
-    LinuxAioState *s = laiocb->ctx;
     int ret;
 
     ret = laiocb->ret;
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
     }
 
     laiocb->ret = ret;
-    aio_context_acquire(s->aio_context);
     if (laiocb->co) {
         /* If the coroutine is already entered it must be in ioq_submit() and
          * will notice laio->ret has been filled in when it eventually runs
@@ -XXX,XX +XXX,XX @@ static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
          * that!
          */
         if (!qemu_coroutine_entered(laiocb->co)) {
-            qemu_coroutine_enter(laiocb->co);
+            aio_co_wake(laiocb->co);
         }
     } else {
         laiocb->common.cb(laiocb->common.opaque, ret);
         qemu_aio_unref(laiocb);
     }
-    aio_context_release(s->aio_context);
 }
 
 /**
diff --git a/block/mirror.c b/block/mirror.c
index XXXXXXX..XXXXXXX 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -XXX,XX +XXX,XX @@ static void mirror_write_complete(void *opaque, int ret)
 {
     MirrorOp *op = opaque;
     MirrorBlockJob *s = op->s;
+
+    aio_context_acquire(blk_get_aio_context(s->common.blk));
     if (ret < 0) {
         BlockErrorAction action;
 
@@ -XXX,XX +XXX,XX @@ static void mirror_write_complete(void *opaque, int ret)
         }
     }
     mirror_iteration_done(op, ret);
+    aio_context_release(blk_get_aio_context(s->common.blk));
 }
 
 static void mirror_read_complete(void *opaque, int ret)
 {
     MirrorOp *op = opaque;
     MirrorBlockJob *s = op->s;
+
+    aio_context_acquire(blk_get_aio_context(s->common.blk));
     if (ret < 0) {
         BlockErrorAction action;
 
@@ -XXX,XX +XXX,XX @@ static void mirror_read_complete(void *opaque, int ret)
         }
 
         mirror_iteration_done(op, ret);
-        return;
+    } else {
+        blk_aio_pwritev(s->target, op->sector_num * BDRV_SECTOR_SIZE, &op->qiov,
+                        0, mirror_write_complete, op);
     }
-    blk_aio_pwritev(s->target, op->sector_num * BDRV_SECTOR_SIZE, &op->qiov,
-                    0, mirror_write_complete, op);
+    aio_context_release(blk_get_aio_context(s->common.blk));
 }
 
 static inline void mirror_clip_sectors(MirrorBlockJob *s,
diff --git a/block/null.c b/block/null.c
index XXXXXXX..XXXXXXX 100644
--- a/block/null.c
+++ b/block/null.c
@@ -XXX,XX +XXX,XX @@ static const AIOCBInfo null_aiocb_info = {
 static void null_bh_cb(void *opaque)
 {
     NullAIOCB *acb = opaque;
-    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
-
-    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, 0);
-    aio_context_release(ctx);
     qemu_aio_unref(acb);
 }
 
 static void null_timer_cb(void *opaque)
 {
     NullAIOCB *acb = opaque;
-    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
-
-    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, 0);
-    aio_context_release(ctx);
     timer_deinit(&acb->timer);
     qemu_aio_unref(acb);
 }
diff --git a/block/qed-cluster.c b/block/qed-cluster.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qed-cluster.c
+++ b/block/qed-cluster.c
@@ -XXX,XX +XXX,XX @@ static void qed_find_cluster_cb(void *opaque, int ret)
     unsigned int index;
     unsigned int n;
 
+    qed_acquire(s);
     if (ret) {
         goto out;
     }
@@ -XXX,XX +XXX,XX @@ static void qed_find_cluster_cb(void *opaque, int ret)
 
 out:
     find_cluster_cb->cb(find_cluster_cb->opaque, ret, offset, len);
+    qed_release(s);
     g_free(find_cluster_cb);
 }
 
diff --git a/block/qed-table.c b/block/qed-table.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qed-table.c
+++ b/block/qed-table.c
@@ -XXX,XX +XXX,XX @@ static void qed_read_table_cb(void *opaque, int ret)
 {
     QEDReadTableCB *read_table_cb = opaque;
     QEDTable *table = read_table_cb->table;
+    BDRVQEDState *s = read_table_cb->s;
     int noffsets = read_table_cb->qiov.size / sizeof(uint64_t);
     int i;
 
@@ -XXX,XX +XXX,XX @@ static void qed_read_table_cb(void *opaque, int ret)
     }
 
     /* Byteswap offsets */
+    qed_acquire(s);
     for (i = 0; i < noffsets; i++) {
         table->offsets[i] = le64_to_cpu(table->offsets[i]);
     }
+    qed_release(s);
 
 out:
     /* Completion */
-    trace_qed_read_table_cb(read_table_cb->s, read_table_cb->table, ret);
+    trace_qed_read_table_cb(s, read_table_cb->table, ret);
     gencb_complete(&read_table_cb->gencb, ret);
 }
 
@@ -XXX,XX +XXX,XX @@ typedef struct {
 static void qed_write_table_cb(void *opaque, int ret)
 {
     QEDWriteTableCB *write_table_cb = opaque;
+    BDRVQEDState *s = write_table_cb->s;
 
-    trace_qed_write_table_cb(write_table_cb->s,
+    trace_qed_write_table_cb(s,
                              write_table_cb->orig_table,
                              write_table_cb->flush,
                              ret);
@@ -XXX,XX +XXX,XX @@ static void qed_write_table_cb(void *opaque, int ret)
     if (write_table_cb->flush) {
         /* We still need to flush first */
         write_table_cb->flush = false;
+        qed_acquire(s);
         bdrv_aio_flush(write_table_cb->s->bs, qed_write_table_cb,
                        write_table_cb);
+        qed_release(s);
         return;
     }
 
@@ -XXX,XX +XXX,XX @@ static void qed_read_l2_table_cb(void *opaque, int ret)
     CachedL2Table *l2_table = request->l2_table;
     uint64_t l2_offset = read_l2_table_cb->l2_offset;
 
+    qed_acquire(s);
     if (ret) {
         /* can't trust loaded L2 table anymore */
         qed_unref_l2_cache_entry(l2_table);
@@ -XXX,XX +XXX,XX @@ static void qed_read_l2_table_cb(void *opaque, int ret)
         request->l2_table = qed_find_l2_cache_entry(&s->l2_cache, l2_offset);
         assert(request->l2_table != NULL);
     }
+    qed_release(s);
 
     gencb_complete(&read_l2_table_cb->gencb, ret);
 }
diff --git a/block/qed.c b/block/qed.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qed.c
+++ b/block/qed.c
@@ -XXX,XX +XXX,XX @@ static void qed_is_allocated_cb(void *opaque, int ret, uint64_t offset, size_t l
     }
 
     if (cb->co) {
-        qemu_coroutine_enter(cb->co);
+        aio_co_wake(cb->co);
     }
 }
 
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn qed_co_pwrite_zeroes_cb(void *opaque, int ret)
     cb->done = true;
     cb->ret = ret;
     if (cb->co) {
-        qemu_coroutine_enter(cb->co);
+        aio_co_wake(cb->co);
     }
 }
 
diff --git a/block/rbd.c b/block/rbd.c
index XXXXXXX..XXXXXXX 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -XXX,XX +XXX,XX @@ shutdown:
 static void qemu_rbd_complete_aio(RADOSCB *rcb)
 {
     RBDAIOCB *acb = rcb->acb;
-    AioContext *ctx = bdrv_get_aio_context(acb->common.bs);
     int64_t r;
 
     r = rcb->ret;
@@ -XXX,XX +XXX,XX @@ static void qemu_rbd_complete_aio(RADOSCB *rcb)
         qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
     }
     qemu_vfree(acb->bounce);
-
-    aio_context_acquire(ctx);
     acb->common.cb(acb->common.opaque, (acb->ret > 0 ? 0 : acb->ret));
-    aio_context_release(ctx);
 
     qemu_aio_unref(acb);
 }
diff --git a/block/win32-aio.c b/block/win32-aio.c
index XXXXXXX..XXXXXXX 100644
--- a/block/win32-aio.c
+++ b/block/win32-aio.c
@@ -XXX,XX +XXX,XX @@ static void win32_aio_process_completion(QEMUWin32AIOState *s,
         qemu_vfree(waiocb->buf);
     }
 
-
-    aio_context_acquire(s->aio_ctx);
     waiocb->common.cb(waiocb->common.opaque, ret);
-    aio_context_release(s->aio_ctx);
     qemu_aio_unref(waiocb);
 }
 
diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -XXX,XX +XXX,XX @@ static int virtio_blk_handle_rw_error(VirtIOBlockReq *req, int error,
 static void virtio_blk_rw_complete(void *opaque, int ret)
 {
     VirtIOBlockReq *next = opaque;
+    VirtIOBlock *s = next->dev;
 
+    aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
     while (next) {
         VirtIOBlockReq *req = next;
         next = req->mr_next;
@@ -XXX,XX +XXX,XX @@ static void virtio_blk_rw_complete(void *opaque, int ret)
         block_acct_done(blk_get_stats(req->dev->blk), &req->acct);
         virtio_blk_free_request(req);
     }
+    aio_context_release(blk_get_aio_context(s->conf.conf.blk));
 }
 
 static void virtio_blk_flush_complete(void *opaque, int ret)
 {
     VirtIOBlockReq *req = opaque;
+    VirtIOBlock *s = req->dev;
 
+    aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
     if (ret) {
         if (virtio_blk_handle_rw_error(req, -ret, 0)) {
-            return;
+            goto out;
         }
     }
 
     virtio_blk_req_complete(req, VIRTIO_BLK_S_OK);
     block_acct_done(blk_get_stats(req->dev->blk), &req->acct);
     virtio_blk_free_request(req);
+
+out:
+    aio_context_release(blk_get_aio_context(s->conf.conf.blk));
 }
 
 #ifdef __linux__
@@ -XXX,XX +XXX,XX @@ static void virtio_blk_ioctl_complete(void *opaque, int status)
     virtio_stl_p(vdev, &scsi->data_len, hdr->dxfer_len);
 
 out:
+    aio_context_acquire(blk_get_aio_context(s->conf.conf.blk));
     virtio_blk_req_complete(req, status);
     virtio_blk_free_request(req);
+    aio_context_release(blk_get_aio_context(s->conf.conf.blk));
     g_free(ioctl_req);
 }
 
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/scsi/scsi-disk.c
+++ b/hw/scsi/scsi-disk.c
@@ -XXX,XX +XXX,XX @@ static void scsi_aio_complete(void *opaque, int ret)
 
     assert(r->req.aiocb != NULL);
     r->req.aiocb = NULL;
+    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
     if (scsi_disk_req_check_error(r, ret, true)) {
         goto done;
     }
@@ -XXX,XX +XXX,XX @@ static void scsi_aio_complete(void *opaque, int ret)
     scsi_req_complete(&r->req, GOOD);
 
 done:
+    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
     scsi_req_unref(&r->req);
 }
 
@@ -XXX,XX +XXX,XX @@ static void scsi_dma_complete(void *opaque, int ret)
     assert(r->req.aiocb != NULL);
     r->req.aiocb = NULL;
 
+    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
     if (ret < 0) {
         block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
     } else {
         block_acct_done(blk_get_stats(s->qdev.conf.blk), &r->acct);
     }
     scsi_dma_complete_noio(r, ret);
+    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
 }
 
 static void scsi_read_complete(void * opaque, int ret)
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
 
     assert(r->req.aiocb != NULL);
     r->req.aiocb = NULL;
+    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
     if (scsi_disk_req_check_error(r, ret, true)) {
         goto done;
     }
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
 
 done:
     scsi_req_unref(&r->req);
+    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
 }
 
 /* Actually issue a read to the block device.  */
@@ -XXX,XX +XXX,XX @@ static void scsi_do_read_cb(void *opaque, int ret)
     assert (r->req.aiocb != NULL);
     r->req.aiocb = NULL;
 
+    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
     if (ret < 0) {
         block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
     } else {
         block_acct_done(blk_get_stats(s->qdev.conf.blk), &r->acct);
     }
     scsi_do_read(opaque, ret);
+    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
 }
 
 /* Read more data from scsi device into buffer.  */
@@ -XXX,XX +XXX,XX @@ static void scsi_write_complete(void * opaque, int ret)
     assert (r->req.aiocb != NULL);
     r->req.aiocb = NULL;
 
+    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
     if (ret < 0) {
         block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
     } else {
         block_acct_done(blk_get_stats(s->qdev.conf.blk), &r->acct);
     }
     scsi_write_complete_noio(r, ret);
+    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
 }
 
 static void scsi_write_data(SCSIRequest *req)
@@ -XXX,XX +XXX,XX @@ static void scsi_unmap_complete(void *opaque, int ret)
 {
     UnmapCBData *data = opaque;
     SCSIDiskReq *r = data->r;
+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
 
     assert(r->req.aiocb != NULL);
     r->req.aiocb = NULL;
 
+    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
     scsi_unmap_complete_noio(data, ret);
+    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
 }
 
 static void scsi_disk_emulate_unmap(SCSIDiskReq *r, uint8_t *inbuf)
@@ -XXX,XX +XXX,XX @@ static void scsi_write_same_complete(void *opaque, int ret)
 
     assert(r->req.aiocb != NULL);
     r->req.aiocb = NULL;
+    aio_context_acquire(blk_get_aio_context(s->qdev.conf.blk));
     if (scsi_disk_req_check_error(r, ret, true)) {
         goto done;
     }
@@ -XXX,XX +XXX,XX @@ done:
     scsi_req_unref(&r->req);
     qemu_vfree(data->iov.iov_base);
     g_free(data);
+    aio_context_release(blk_get_aio_context(s->qdev.conf.blk));
 }
 
 static void scsi_disk_emulate_write_same(SCSIDiskReq *r, uint8_t *inbuf)
diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -XXX,XX +XXX,XX @@ done:
 static void scsi_command_complete(void *opaque, int ret)
 {
     SCSIGenericReq *r = (SCSIGenericReq *)opaque;
+    SCSIDevice *s = r->req.dev;
 
     assert(r->req.aiocb != NULL);
     r->req.aiocb = NULL;
+
+    aio_context_acquire(blk_get_aio_context(s->conf.blk));
     scsi_command_complete_noio(r, ret);
+    aio_context_release(blk_get_aio_context(s->conf.blk));
 }
 
 static int execute_command(BlockBackend *blk,
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
     assert(r->req.aiocb != NULL);
     r->req.aiocb = NULL;
 
+    aio_context_acquire(blk_get_aio_context(s->conf.blk));
+
     if (ret || r->req.io_canceled) {
         scsi_command_complete_noio(r, ret);
-        return;
+        goto done;
     }
 
     len = r->io_header.dxfer_len - r->io_header.resid;
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
     r->len = -1;
     if (len == 0) {
         scsi_command_complete_noio(r, 0);
-        return;
+        goto done;
     }
 
     /* Snoop READ CAPACITY output to set the blocksize.  */
@@ -XXX,XX +XXX,XX @@ static void scsi_read_complete(void * opaque, int ret)
     }
     scsi_req_data(&r->req, len);
     scsi_req_unref(&r->req);
+
+done:
+    aio_context_release(blk_get_aio_context(s->conf.blk));
 }
 
 /* Read more data from scsi device into buffer.  */
@@ -XXX,XX +XXX,XX @@ static void scsi_write_complete(void * opaque, int ret)
     assert(r->req.aiocb != NULL);
     r->req.aiocb = NULL;
 
+    aio_context_acquire(blk_get_aio_context(s->conf.blk));
+
     if (ret || r->req.io_canceled) {
         scsi_command_complete_noio(r, ret);
-        return;
+        goto done;
     }
 
     if (r->req.cmd.buf[0] == MODE_SELECT && r->req.cmd.buf[4] == 12 &&
@@ -XXX,XX +XXX,XX @@ static void scsi_write_complete(void * opaque, int ret)
     }
 
     scsi_command_complete_noio(r, ret);
+
+done:
+    aio_context_release(blk_get_aio_context(s->conf.blk));
 }
 
 /* Write data to a scsi device.  Returns nonzero on failure.
diff --git a/util/thread-pool.c b/util/thread-pool.c
index XXXXXXX..XXXXXXX 100644
--- a/util/thread-pool.c
+++ b/util/thread-pool.c
@@ -XXX,XX +XXX,XX @@ restart:
              */
             qemu_bh_schedule(pool->completion_bh);
 
+            aio_context_release(pool->ctx);
             elem->common.cb(elem->common.opaque, elem->ret);
+            aio_context_acquire(pool->ctx);
             qemu_aio_unref(elem);
             goto restart;
         } else {
@@ -XXX,XX +XXX,XX @@ static void thread_pool_co_cb(void *opaque, int ret)
     ThreadPoolCo *co = opaque;
 
     co->ret = ret;
-    qemu_coroutine_enter(co->co);
+    aio_co_wake(co->co);
 }
 
 int coroutine_fn thread_pool_submit_co(ThreadPool *pool, ThreadPoolFunc *func,
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

This patch prepares for the removal of unnecessary lockcnt inc/dec pairs.
Extract the dispatching loop for file descriptor handlers into a new
function aio_dispatch_handlers, and then inline aio_dispatch into
aio_poll.

aio_dispatch can now become void.

diff --git a/include/block/aio.h b/include/block/aio.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -XXX,XX +XXX,XX @@ bool aio_pending(AioContext *ctx);
 /* Dispatch any pending callbacks from the GSource attached to the AioContext.
  *
  * This is used internally in the implementation of the GSource.
- *
- * @dispatch_fds: true to process fds, false to skip them
- *                (can be used as an optimization by callers that know there
- *                are no fds ready)
  */
-bool aio_dispatch(AioContext *ctx, bool dispatch_fds);
+void aio_dispatch(AioContext *ctx);
 
 /* Progress in completing AIO work to occur.  This can issue new pending
  * aio as a result of executing I/O completion or bh callbacks.
diff --git a/util/aio-posix.c b/util/aio-posix.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
     AioHandler *node, *tmp;
     bool progress = false;
 
-    /*
-     * We have to walk very carefully in case aio_set_fd_handler is
-     * called while we're walking.
-     */
-    qemu_lockcnt_inc(&ctx->list_lock);
-
     QLIST_FOREACH_SAFE_RCU(node, &ctx->aio_handlers, node, tmp) {
         int revents;
 
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
         }
     }
 
-    qemu_lockcnt_dec(&ctx->list_lock);
     return progress;
 }
 
-/*
- * Note that dispatch_fds == false has the side-effect of post-poning the
- * freeing of deleted handlers.
- */
-bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
+void aio_dispatch(AioContext *ctx)
 {
-    bool progress;
+    aio_bh_poll(ctx);
 
-    /*
-     * If there are callbacks left that have been queued, we need to call them.
-     * Do not call select in this case, because it is possible that the caller
-     * does not need a complete flush (as is the case for aio_poll loops).
-     */
-    progress = aio_bh_poll(ctx);
+    qemu_lockcnt_inc(&ctx->list_lock);
+    aio_dispatch_handlers(ctx);
+    qemu_lockcnt_dec(&ctx->list_lock);
 
-    if (dispatch_fds) {
-        progress |= aio_dispatch_handlers(ctx);
-    }
-
-    /* Run our timers */
-    progress |= timerlistgroup_run_timers(&ctx->tlg);
-
-    return progress;
+    timerlistgroup_run_timers(&ctx->tlg);
 }
 
 /* These thread-local variables are used only in a small part of aio_poll
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
     npfd = 0;
     qemu_lockcnt_dec(&ctx->list_lock);
 
-    /* Run dispatch even if there were no readable fds to run timers */
-    if (aio_dispatch(ctx, ret > 0)) {
-        progress = true;
+    progress |= aio_bh_poll(ctx);
+
+    if (ret > 0) {
+        qemu_lockcnt_inc(&ctx->list_lock);
+        progress |= aio_dispatch_handlers(ctx);
+        qemu_lockcnt_dec(&ctx->list_lock);
     }
 
+    progress |= timerlistgroup_run_timers(&ctx->tlg);
+
     return progress;
 }
 
diff --git a/util/aio-win32.c b/util/aio-win32.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-win32.c
+++ b/util/aio-win32.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
     return progress;
 }
 
-bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
+void aio_dispatch(AioContext *ctx)
 {
-    bool progress;
-
-    progress = aio_bh_poll(ctx);
-    if (dispatch_fds) {
-        progress |= aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);
-    }
-    progress |= timerlistgroup_run_timers(&ctx->tlg);
-    return progress;
+    aio_bh_poll(ctx);
+    aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);
+    timerlistgroup_run_timers(&ctx->tlg);
 }
 
 bool aio_poll(AioContext *ctx, bool blocking)
diff --git a/util/async.c b/util/async.c
index XXXXXXX..XXXXXXX 100644
--- a/util/async.c
+++ b/util/async.c
@@ -XXX,XX +XXX,XX @@ aio_ctx_dispatch(GSource     *source,
     AioContext *ctx = (AioContext *) source;
 
     assert(callback == NULL);
-    aio_dispatch(ctx, true);
+    aio_dispatch(ctx);
     return true;
 }
 
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

Pull the increment/decrement pair out of aio_bh_poll and into the
callers.

diff --git a/util/aio-posix.c b/util/aio-posix.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx)
 
 void aio_dispatch(AioContext *ctx)
 {
+    qemu_lockcnt_inc(&ctx->list_lock);
     aio_bh_poll(ctx);
-
-    qemu_lockcnt_inc(&ctx->list_lock);
     aio_dispatch_handlers(ctx);
     qemu_lockcnt_dec(&ctx->list_lock);
 
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
     }
 
     npfd = 0;
-    qemu_lockcnt_dec(&ctx->list_lock);
 
     progress |= aio_bh_poll(ctx);
 
     if (ret > 0) {
-        qemu_lockcnt_inc(&ctx->list_lock);
         progress |= aio_dispatch_handlers(ctx);
-        qemu_lockcnt_dec(&ctx->list_lock);
     }
 
+    qemu_lockcnt_dec(&ctx->list_lock);
+
     progress |= timerlistgroup_run_timers(&ctx->tlg);
 
     return progress;
diff --git a/util/aio-win32.c b/util/aio-win32.c
index XXXXXXX..XXXXXXX 100644
--- a/util/aio-win32.c
+++ b/util/aio-win32.c
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
     bool progress = false;
     AioHandler *tmp;
 
-    qemu_lockcnt_inc(&ctx->list_lock);
-
     /*
      * We have to walk very carefully in case aio_set_fd_handler is
      * called while we're walking.
@@ -XXX,XX +XXX,XX @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE event)
         }
     }
 
-    qemu_lockcnt_dec(&ctx->list_lock);
     return progress;
 }
 
 void aio_dispatch(AioContext *ctx)
 {
+    qemu_lockcnt_inc(&ctx->list_lock);
     aio_bh_poll(ctx);
     aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);
+    qemu_lockcnt_dec(&ctx->list_lock);
     timerlistgroup_run_timers(&ctx->tlg);
 }
 
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
         }
     }
 
-    qemu_lockcnt_dec(&ctx->list_lock);
     first = true;
 
     /* ctx->notifier is always registered.  */
@@ -XXX,XX +XXX,XX @@ bool aio_poll(AioContext *ctx, bool blocking)
         progress |= aio_dispatch_handlers(ctx, event);
     } while (count > 0);
 
+    qemu_lockcnt_dec(&ctx->list_lock);
+
     progress |= timerlistgroup_run_timers(&ctx->tlg);
     return progress;
 }
diff --git a/util/async.c b/util/async.c
index XXXXXXX..XXXXXXX 100644
--- a/util/async.c
+++ b/util/async.c
@@ -XXX,XX +XXX,XX @@ void aio_bh_call(QEMUBH *bh)
     bh->cb(bh->opaque);
 }
 
-/* Multiple occurrences of aio_bh_poll cannot be called concurrently */
+/* Multiple occurrences of aio_bh_poll cannot be called concurrently.
+ * The count in ctx->list_lock is incremented before the call, and is
+ * not affected by the call.
+ */
 int aio_bh_poll(AioContext *ctx)
 {
     QEMUBH *bh, **bhp, *next;
     int ret;
     bool deleted = false;
 
-    qemu_lockcnt_inc(&ctx->list_lock);
-
     ret = 0;
     for (bh = atomic_rcu_read(&ctx->first_bh); bh; bh = next) {
         next = atomic_rcu_read(&bh->next);
@@ -XXX,XX +XXX,XX @@ int aio_bh_poll(AioContext *ctx)
 
     /* remove deleted bhs */
     if (!deleted) {
-        qemu_lockcnt_dec(&ctx->list_lock);
         return ret;
     }
 
-    if (qemu_lockcnt_dec_and_lock(&ctx->list_lock)) {
+    if (qemu_lockcnt_dec_if_lock(&ctx->list_lock)) {
         bhp = &ctx->first_bh;
         while (*bhp) {
             bh = *bhp;
@@ -XXX,XX +XXX,XX @@ int aio_bh_poll(AioContext *ctx)
                 bhp = &bh->next;
             }
         }
-        qemu_lockcnt_unlock(&ctx->list_lock);
+        qemu_lockcnt_inc_and_unlock(&ctx->list_lock);
     }
     return ret;
 }
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/include/block/block_int.h b/include/block/block_int.h
index XXXXXXX..XXXXXXX 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -XXX,XX +XXX,XX @@ struct BdrvChild {
  * copied as well.
  */
 struct BlockDriverState {
-    int64_t total_sectors; /* if we are reading a disk image, give its
-                              size in sectors */
+    /* Protected by big QEMU lock or read-only after opening.  No special
+     * locking needed during I/O...
+     */
     int open_flags; /* flags used to open the file, re-used for re-open */
     bool read_only; /* if true, the media is read only */
     bool encrypted; /* if true, the media is encrypted */
@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
     bool sg;        /* if true, the device is a /dev/sg* */
     bool probed;    /* if true, format was probed rather than specified */
 
-    int copy_on_read; /* if nonzero, copy read backing sectors into image.
-                         note this is a reference count */
-
-    CoQueue flush_queue;            /* Serializing flush queue */
-    bool active_flush_req;          /* Flush request in flight? */
-    unsigned int write_gen;         /* Current data generation */
-    unsigned int flushed_gen;       /* Flushed write generation */
-
     BlockDriver *drv; /* NULL means no media */
     void *opaque;
 
@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
     BdrvChild *backing;
     BdrvChild *file;
 
-    /* Callback before write request is processed */
-    NotifierWithReturnList before_write_notifiers;
-
-    /* number of in-flight requests; overall and serialising */
-    unsigned int in_flight;
-    unsigned int serialising_in_flight;
-
-    bool wakeup;
-
-    /* Offset after the highest byte written to */
-    uint64_t wr_highest_offset;
-
     /* I/O Limits */
     BlockLimits bl;
 
@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
     QTAILQ_ENTRY(BlockDriverState) bs_list;
     /* element of the list of monitor-owned BDS */
     QTAILQ_ENTRY(BlockDriverState) monitor_list;
-    QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
     int refcnt;
 
-    QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
-
     /* operation blockers */
     QLIST_HEAD(, BdrvOpBlocker) op_blockers[BLOCK_OP_TYPE_MAX];
 
@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
     /* The error object in use for blocking operations on backing_hd */
     Error *backing_blocker;
 
+    /* Protected by AioContext lock */
+
+    /* If true, copy read backing sectors into image.  Can be >1 if more
+     * than one client has requested copy-on-read.
+     */
+    int copy_on_read;
+
+    /* If we are reading a disk image, give its size in sectors.
+     * Generally read-only; it is written to by load_vmstate and save_vmstate,
+     * but the block layer is quiescent during those.
+     */
+    int64_t total_sectors;
+
+    /* Callback before write request is processed */
+    NotifierWithReturnList before_write_notifiers;
+
+    /* number of in-flight requests; overall and serialising */
+    unsigned int in_flight;
+    unsigned int serialising_in_flight;
+
+    bool wakeup;
+
+    /* Offset after the highest byte written to */
+    uint64_t wr_highest_offset;
+
     /* threshold limit for writes, in bytes. "High water mark". */
     uint64_t write_threshold_offset;
     NotifierWithReturn write_threshold_notifier;
@@ -XXX,XX +XXX,XX @@ struct BlockDriverState {
     /* counter for nested bdrv_io_plug */
     unsigned io_plugged;
 
+    QLIST_HEAD(, BdrvTrackedRequest) tracked_requests;
+    CoQueue flush_queue;                  /* Serializing flush queue */
+    bool active_flush_req;                /* Flush request in flight? */
+    unsigned int write_gen;               /* Current data generation */
+    unsigned int flushed_gen;             /* Flushed write generation */
+
+    QLIST_HEAD(, BdrvDirtyBitmap) dirty_bitmaps;
+
+    /* do we need to tell the quest if we have a volatile write cache? */
+    int enable_write_cache;
+
     int quiesce_counter;
 };
 
diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index XXXXXXX..XXXXXXX 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -XXX,XX +XXX,XX @@ typedef struct BlockDevOps {
  * fields that must be public. This is in particular for QLIST_ENTRY() and
  * friends so that BlockBackends can be kept in lists outside block-backend.c */
 typedef struct BlockBackendPublic {
-    /* I/O throttling.
-     * throttle_state tells us if this BlockBackend has I/O limits configured.
-     * io_limits_disabled tells us if they are currently being enforced */
+    /* I/O throttling has its own locking, but also some fields are
+     * protected by the AioContext lock.
+     */
+
+    /* Protected by AioContext lock.  */
     CoQueue      throttled_reqs[2];
+
+    /* Nonzero if the I/O limits are currently being ignored; generally
+     * it is zero.  */
     unsigned int io_limits_disabled;
 
     /* The following fields are protected by the ThrottleGroup lock.
-     * See the ThrottleGroup documentation for details. */
+     * See the ThrottleGroup documentation for details.
+     * throttle_state tells us if I/O limits are configured. */
     ThrottleState *throttle_state;
     ThrottleTimers throttle_timers;
     unsigned       pending_reqs[2];
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

This uses the lock-free mutex described in the paper '"Blocking without
Locking", or LFTHREADS: A lock-free thread library' by Gidenstam and
Papatriantafilou.  The same technique is used in OSv, and in fact
the code is essentially a conversion to C of OSv's code.

[Added missing coroutine_fn in tests/test-aio-multithread.c.
--Stefan]

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213181244.16297-2-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/qemu/coroutine.h     |  17 ++++-
 tests/test-aio-multithread.c |  86 ++++++++++++++++++++++++
 util/qemu-coroutine-lock.c   | 155 ++++++++++++++++++++++++++++++++++++++++---
 util/trace-events            |   1 +
 4 files changed, 246 insertions(+), 13 deletions(-)

diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -XXX,XX +XXX,XX @@ bool qemu_co_queue_empty(CoQueue *queue);
 /**
  * Provides a mutex that can be used to synchronise coroutines
  */
+struct CoWaitRecord;
 typedef struct CoMutex {
-    bool locked;
+    /* Count of pending lockers; 0 for a free mutex, 1 for an
+     * uncontended mutex.
+     */
+    unsigned locked;
+
+    /* A queue of waiters.  Elements are added atomically in front of
+     * from_push.  to_pop is only populated, and popped from, by whoever
+     * is in charge of the next wakeup.  This can be an unlocker or,
+     * through the handoff protocol, a locker that is about to go to sleep.
+     */
+    QSLIST_HEAD(, CoWaitRecord) from_push, to_pop;
+
+    unsigned handoff, sequence;
+
     Coroutine *holder;
-    CoQueue queue;
 } CoMutex;
 
 /**
diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-aio-multithread.c
+++ b/tests/test-aio-multithread.c
@@ -XXX,XX +XXX,XX @@ static void test_multi_co_schedule_10(void)
     test_multi_co_schedule(10);
 }
 
+/* CoMutex thread-safety.  */
+
+static uint32_t atomic_counter;
+static uint32_t running;
+static uint32_t counter;
+static CoMutex comutex;
+
+static void coroutine_fn test_multi_co_mutex_entry(void *opaque)
+{
+    while (!atomic_mb_read(&now_stopping)) {
+        qemu_co_mutex_lock(&comutex);
+        counter++;
+        qemu_co_mutex_unlock(&comutex);
+
+        /* Increase atomic_counter *after* releasing the mutex.  Otherwise
+         * there is a chance (it happens about 1 in 3 runs) that the iothread
+         * exits before the coroutine is woken up, causing a spurious
+         * assertion failure.
+         */
+        atomic_inc(&atomic_counter);
+    }
+    atomic_dec(&running);
+}
+
+static void test_multi_co_mutex(int threads, int seconds)
+{
+    int i;
+
+    qemu_co_mutex_init(&comutex);
+    counter = 0;
+    atomic_counter = 0;
+    now_stopping = false;
+
+    create_aio_contexts();
+    assert(threads <= NUM_CONTEXTS);
+    running = threads;
+    for (i = 0; i < threads; i++) {
+        Coroutine *co1 = qemu_coroutine_create(test_multi_co_mutex_entry, NULL);
+        aio_co_schedule(ctx[i], co1);
+    }
+
+    g_usleep(seconds * 1000000);
+
+    atomic_mb_set(&now_stopping, true);
+    while (running > 0) {
+        g_usleep(100000);
+    }
+
+    join_aio_contexts();
+    g_test_message("%d iterations/second\n", counter / seconds);
+    g_assert_cmpint(counter, ==, atomic_counter);
+}
+
+/* Testing with NUM_CONTEXTS threads focuses on the queue.  The mutex however
+ * is too contended (and the threads spend too much time in aio_poll)
+ * to actually stress the handoff protocol.
+ */
+static void test_multi_co_mutex_1(void)
+{
+    test_multi_co_mutex(NUM_CONTEXTS, 1);
+}
+
+static void test_multi_co_mutex_10(void)
+{
+    test_multi_co_mutex(NUM_CONTEXTS, 10);
+}
+
+/* Testing with fewer threads stresses the handoff protocol too.  Still, the
+ * case where the locker _can_ pick up a handoff is very rare, happening
+ * about 10 times in 1 million, so increase the runtime a bit compared to
+ * other "quick" testcases that only run for 1 second.
+ */
+static void test_multi_co_mutex_2_3(void)
+{
+    test_multi_co_mutex(2, 3);
+}
+
+static void test_multi_co_mutex_2_30(void)
+{
+    test_multi_co_mutex(2, 30);
+}
+
 /* End of tests.  */
 
 int main(int argc, char **argv)
@@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv)
     g_test_add_func("/aio/multi/lifecycle", test_lifecycle);
     if (g_test_quick()) {
         g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_1);
+        g_test_add_func("/aio/multi/mutex/contended", test_multi_co_mutex_1);
+        g_test_add_func("/aio/multi/mutex/handoff", test_multi_co_mutex_2_3);
     } else {
         g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_10);
+        g_test_add_func("/aio/multi/mutex/contended", test_multi_co_mutex_10);
+        g_test_add_func("/aio/multi/mutex/handoff", test_multi_co_mutex_2_30);
     }
     return g_test_run();
 }
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index XXXXXXX..XXXXXXX 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -XXX,XX +XXX,XX @@
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
+ *
+ * The lock-free mutex implementation is based on OSv
+ * (core/lfmutex.cc, include/lockfree/mutex.hh).
+ * Copyright (C) 2013 Cloudius Systems, Ltd.
  */
 
 #include "qemu/osdep.h"
@@ -XXX,XX +XXX,XX @@ bool qemu_co_queue_empty(CoQueue *queue)
     return QSIMPLEQ_FIRST(&queue->entries) == NULL;
 }
 
+/* The wait records are handled with a multiple-producer, single-consumer
+ * lock-free queue.  There cannot be two concurrent pop_waiter() calls
+ * because pop_waiter() can only be called while mutex->handoff is zero.
+ * This can happen in three cases:
+ * - in qemu_co_mutex_unlock, before the hand-off protocol has started.
+ *   In this case, qemu_co_mutex_lock will see mutex->handoff == 0 and
+ *   not take part in the handoff.
+ * - in qemu_co_mutex_lock, if it steals the hand-off responsibility from
+ *   qemu_co_mutex_unlock.  In this case, qemu_co_mutex_unlock will fail
+ *   the cmpxchg (it will see either 0 or the next sequence value) and
+ *   exit.  The next hand-off cannot begin until qemu_co_mutex_lock has
+ *   woken up someone.
+ * - in qemu_co_mutex_unlock, if it takes the hand-off token itself.
+ *   In this case another iteration starts with mutex->handoff == 0;
+ *   a concurrent qemu_co_mutex_lock will fail the cmpxchg, and
+ *   qemu_co_mutex_unlock will go back to case (1).
+ *
+ * The following functions manage this queue.
+ */
+typedef struct CoWaitRecord {
+    Coroutine *co;
+    QSLIST_ENTRY(CoWaitRecord) next;
+} CoWaitRecord;
+
+static void push_waiter(CoMutex *mutex, CoWaitRecord *w)
+{
+    w->co = qemu_coroutine_self();
+    QSLIST_INSERT_HEAD_ATOMIC(&mutex->from_push, w, next);
+}
+
+static void move_waiters(CoMutex *mutex)
+{
+    QSLIST_HEAD(, CoWaitRecord) reversed;
+    QSLIST_MOVE_ATOMIC(&reversed, &mutex->from_push);
+    while (!QSLIST_EMPTY(&reversed)) {
+        CoWaitRecord *w = QSLIST_FIRST(&reversed);
+        QSLIST_REMOVE_HEAD(&reversed, next);
+        QSLIST_INSERT_HEAD(&mutex->to_pop, w, next);
+    }
+}
+
+static CoWaitRecord *pop_waiter(CoMutex *mutex)
+{
+    CoWaitRecord *w;
+
+    if (QSLIST_EMPTY(&mutex->to_pop)) {
+        move_waiters(mutex);
+        if (QSLIST_EMPTY(&mutex->to_pop)) {
+            return NULL;
+        }
+    }
+    w = QSLIST_FIRST(&mutex->to_pop);
+    QSLIST_REMOVE_HEAD(&mutex->to_pop, next);
+    return w;
+}
+
+static bool has_waiters(CoMutex *mutex)
+{
+    return QSLIST_EMPTY(&mutex->to_pop) || QSLIST_EMPTY(&mutex->from_push);
+}
+
 void qemu_co_mutex_init(CoMutex *mutex)
 {
     memset(mutex, 0, sizeof(*mutex));
-    qemu_co_queue_init(&mutex->queue);
 }
 
-void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
+static void coroutine_fn qemu_co_mutex_lock_slowpath(CoMutex *mutex)
 {
     Coroutine *self = qemu_coroutine_self();
+    CoWaitRecord w;
+    unsigned old_handoff;
 
     trace_qemu_co_mutex_lock_entry(mutex, self);
+    w.co = self;
+    push_waiter(mutex, &w);
 
-    while (mutex->locked) {
-        qemu_co_queue_wait(&mutex->queue);
+    /* This is the "Responsibility Hand-Off" protocol; a lock() picks from
+     * a concurrent unlock() the responsibility of waking somebody up.
+     */
+    old_handoff = atomic_mb_read(&mutex->handoff);
+    if (old_handoff &&
+        has_waiters(mutex) &&
+        atomic_cmpxchg(&mutex->handoff, old_handoff, 0) == old_handoff) {
+        /* There can be no concurrent pops, because there can be only
+         * one active handoff at a time.
+         */
+        CoWaitRecord *to_wake = pop_waiter(mutex);
+        Coroutine *co = to_wake->co;
+        if (co == self) {
+            /* We got the lock ourselves!  */
+            assert(to_wake == &w);
+            return;
+        }
+
+        aio_co_wake(co);
     }
 
-    mutex->locked = true;
-    mutex->holder = self;
-    self->locks_held++;
-
+    qemu_coroutine_yield();
     trace_qemu_co_mutex_lock_return(mutex, self);
 }
 
+void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
+{
+    Coroutine *self = qemu_coroutine_self();
+
+    if (atomic_fetch_inc(&mutex->locked) == 0) {
+        /* Uncontended.  */
+        trace_qemu_co_mutex_lock_uncontended(mutex, self);
+    } else {
+        qemu_co_mutex_lock_slowpath(mutex);
+    }
+    mutex->holder = self;
+    self->locks_held++;
+}
+
 void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
 {
     Coroutine *self = qemu_coroutine_self();
 
     trace_qemu_co_mutex_unlock_entry(mutex, self);
 
-    assert(mutex->locked == true);
+    assert(mutex->locked);
     assert(mutex->holder == self);
     assert(qemu_in_coroutine());
 
-    mutex->locked = false;
     mutex->holder = NULL;
     self->locks_held--;
-    qemu_co_queue_next(&mutex->queue);
+    if (atomic_fetch_dec(&mutex->locked) == 1) {
+        /* No waiting qemu_co_mutex_lock().  Pfew, that was easy!  */
+        return;
+    }
+
+    for (;;) {
+        CoWaitRecord *to_wake = pop_waiter(mutex);
+        unsigned our_handoff;
+
+        if (to_wake) {
+            Coroutine *co = to_wake->co;
+            aio_co_wake(co);
+            break;
+        }
+
+        /* Some concurrent lock() is in progress (we know this because
+         * mutex->locked was >1) but it hasn't yet put itself on the wait
+         * queue.  Pick a sequence number for the handoff protocol (not 0).
+         */
+        if (++mutex->sequence == 0) {
+            mutex->sequence = 1;
+        }
+
+        our_handoff = mutex->sequence;
+        atomic_mb_set(&mutex->handoff, our_handoff);
+        if (!has_waiters(mutex)) {
+            /* The concurrent lock has not added itself yet, so it
+             * will be able to pick our handoff.
+             */
+            break;
+        }
+
+        /* Try to do the handoff protocol ourselves; if somebody else has
+         * already taken it, however, we're done and they're responsible.
+         */
+        if (atomic_cmpxchg(&mutex->handoff, our_handoff, 0) != our_handoff) {
+            break;
+        }
+    }
 
     trace_qemu_co_mutex_unlock_return(mutex, self);
 }
diff --git a/util/trace-events b/util/trace-events
index XXXXXXX..XXXXXXX 100644
--- a/util/trace-events
+++ b/util/trace-events
@@ -XXX,XX +XXX,XX @@ qemu_coroutine_terminate(void *co) "self %p"
 
 # util/qemu-coroutine-lock.c
 qemu_co_queue_run_restart(void *co) "co %p"
+qemu_co_mutex_lock_uncontended(void *mutex, void *self) "mutex %p self %p"
 qemu_co_mutex_lock_entry(void *mutex, void *self) "mutex %p self %p"
 qemu_co_mutex_lock_return(void *mutex, void *self) "mutex %p self %p"
 qemu_co_mutex_unlock_entry(void *mutex, void *self) "mutex %p self %p"
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

Running a very small critical section on pthread_mutex_t and CoMutex
shows that pthread_mutex_t is much faster because it doesn't actually
go to sleep.  What happens is that the critical section is shorter
than the latency of entering the kernel and thus FUTEX_WAIT always
fails.  With CoMutex there is no such latency but you still want to
avoid wait and wakeup.  So introduce it artificially.

This only works with one waiters; because CoMutex is fair, it will
always have more waits and wakeups than a pthread_mutex_t.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213181244.16297-3-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/qemu/coroutine.h   |  5 +++++
 util/qemu-coroutine-lock.c | 51 ++++++++++++++++++++++++++++++++++++++++------
 util/qemu-coroutine.c      |  2 +-
 3 files changed, 51 insertions(+), 7 deletions(-)

diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -XXX,XX +XXX,XX @@ typedef struct CoMutex {
      */
     unsigned locked;
 
+    /* Context that is holding the lock.  Useful to avoid spinning
+     * when two coroutines on the same AioContext try to get the lock. :)
+     */
+    AioContext *ctx;
+
     /* A queue of waiters.  Elements are added atomically in front of
      * from_push.  to_pop is only populated, and popped from, by whoever
      * is in charge of the next wakeup.  This can be an unlocker or,
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index XXXXXXX..XXXXXXX 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -XXX,XX +XXX,XX @@
 #include "qemu-common.h"
 #include "qemu/coroutine.h"
 #include "qemu/coroutine_int.h"
+#include "qemu/processor.h"
 #include "qemu/queue.h"
 #include "block/aio.h"
 #include "trace.h"
@@ -XXX,XX +XXX,XX @@ void qemu_co_mutex_init(CoMutex *mutex)
     memset(mutex, 0, sizeof(*mutex));
 }
 
-static void coroutine_fn qemu_co_mutex_lock_slowpath(CoMutex *mutex)
+static void coroutine_fn qemu_co_mutex_wake(CoMutex *mutex, Coroutine *co)
+{
+    /* Read co before co->ctx; pairs with smp_wmb() in
+     * qemu_coroutine_enter().
+     */
+    smp_read_barrier_depends();
+    mutex->ctx = co->ctx;
+    aio_co_wake(co);
+}
+
+static void coroutine_fn qemu_co_mutex_lock_slowpath(AioContext *ctx,
+                                                     CoMutex *mutex)
 {
     Coroutine *self = qemu_coroutine_self();
     CoWaitRecord w;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn qemu_co_mutex_lock_slowpath(CoMutex *mutex)
         if (co == self) {
             /* We got the lock ourselves!  */
             assert(to_wake == &w);
+            mutex->ctx = ctx;
             return;
         }
 
-        aio_co_wake(co);
+        qemu_co_mutex_wake(mutex, co);
     }
 
     qemu_coroutine_yield();
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn qemu_co_mutex_lock_slowpath(CoMutex *mutex)
 
 void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
 {
+    AioContext *ctx = qemu_get_current_aio_context();
     Coroutine *self = qemu_coroutine_self();
+    int waiters, i;
 
-    if (atomic_fetch_inc(&mutex->locked) == 0) {
+    /* Running a very small critical section on pthread_mutex_t and CoMutex
+     * shows that pthread_mutex_t is much faster because it doesn't actually
+     * go to sleep.  What happens is that the critical section is shorter
+     * than the latency of entering the kernel and thus FUTEX_WAIT always
+     * fails.  With CoMutex there is no such latency but you still want to
+     * avoid wait and wakeup.  So introduce it artificially.
+     */
+    i = 0;
+retry_fast_path:
+    waiters = atomic_cmpxchg(&mutex->locked, 0, 1);
+    if (waiters != 0) {
+        while (waiters == 1 && ++i < 1000) {
+            if (atomic_read(&mutex->ctx) == ctx) {
+                break;
+            }
+            if (atomic_read(&mutex->locked) == 0) {
+                goto retry_fast_path;
+            }
+            cpu_relax();
+        }
+        waiters = atomic_fetch_inc(&mutex->locked);
+    }
+
+    if (waiters == 0) {
         /* Uncontended.  */
         trace_qemu_co_mutex_lock_uncontended(mutex, self);
+        mutex->ctx = ctx;
     } else {
-        qemu_co_mutex_lock_slowpath(mutex);
+        qemu_co_mutex_lock_slowpath(ctx, mutex);
     }
     mutex->holder = self;
     self->locks_held++;
@@ -XXX,XX +XXX,XX @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
     assert(mutex->holder == self);
     assert(qemu_in_coroutine());
 
+    mutex->ctx = NULL;
     mutex->holder = NULL;
     self->locks_held--;
     if (atomic_fetch_dec(&mutex->locked) == 1) {
@@ -XXX,XX +XXX,XX @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
         unsigned our_handoff;
 
         if (to_wake) {
-            Coroutine *co = to_wake->co;
-            aio_co_wake(co);
+            qemu_co_mutex_wake(mutex, to_wake->co);
             break;
         }
 
diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
index XXXXXXX..XXXXXXX 100644
--- a/util/qemu-coroutine.c
+++ b/util/qemu-coroutine.c
@@ -XXX,XX +XXX,XX @@ void qemu_coroutine_enter(Coroutine *co)
     co->ctx = qemu_get_current_aio_context();
 
     /* Store co->ctx before anything that stores co.  Matches
-     * barrier in aio_co_wake.
+     * barrier in aio_co_wake and qemu_co_mutex_wake.
      */
     smp_wmb();
 
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

Add two implementations of the same benchmark as the previous patch,
but using pthreads.  One uses a normal QemuMutex, the other is Linux
only and implements a fair mutex based on MCS locks and futexes.
This shows that the slower performance of the 5-thread case is due to
the fairness of CoMutex, rather than to coroutines.  If fairness does
not matter, as is the case with two threads, CoMutex can actually be
faster than pthreads.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213181244.16297-4-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 tests/test-aio-multithread.c | 164 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)

diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-aio-multithread.c
+++ b/tests/test-aio-multithread.c
@@ -XXX,XX +XXX,XX @@ static void test_multi_co_mutex_2_30(void)
     test_multi_co_mutex(2, 30);
 }
 
+/* Same test with fair mutexes, for performance comparison.  */
+
+#ifdef CONFIG_LINUX
+#include "qemu/futex.h"
+
+/* The nodes for the mutex reside in this structure (on which we try to avoid
+ * false sharing).  The head of the mutex is in the "mutex_head" variable.
+ */
+static struct {
+    int next, locked;
+    int padding[14];
+} nodes[NUM_CONTEXTS] __attribute__((__aligned__(64)));
+
+static int mutex_head = -1;
+
+static void mcs_mutex_lock(void)
+{
+    int prev;
+
+    nodes[id].next = -1;
+    nodes[id].locked = 1;
+    prev = atomic_xchg(&mutex_head, id);
+    if (prev != -1) {
+        atomic_set(&nodes[prev].next, id);
+        qemu_futex_wait(&nodes[id].locked, 1);
+    }
+}
+
+static void mcs_mutex_unlock(void)
+{
+    int next;
+    if (nodes[id].next == -1) {
+        if (atomic_read(&mutex_head) == id &&
+            atomic_cmpxchg(&mutex_head, id, -1) == id) {
+            /* Last item in the list, exit.  */
+            return;
+        }
+        while (atomic_read(&nodes[id].next) == -1) {
+            /* mcs_mutex_lock did the xchg, but has not updated
+             * nodes[prev].next yet.
+             */
+        }
+    }
+
+    /* Wake up the next in line.  */
+    next = nodes[id].next;
+    nodes[next].locked = 0;
+    qemu_futex_wake(&nodes[next].locked, 1);
+}
+
+static void test_multi_fair_mutex_entry(void *opaque)
+{
+    while (!atomic_mb_read(&now_stopping)) {
+        mcs_mutex_lock();
+        counter++;
+        mcs_mutex_unlock();
+        atomic_inc(&atomic_counter);
+    }
+    atomic_dec(&running);
+}
+
+static void test_multi_fair_mutex(int threads, int seconds)
+{
+    int i;
+
+    assert(mutex_head == -1);
+    counter = 0;
+    atomic_counter = 0;
+    now_stopping = false;
+
+    create_aio_contexts();
+    assert(threads <= NUM_CONTEXTS);
+    running = threads;
+    for (i = 0; i < threads; i++) {
+        Coroutine *co1 = qemu_coroutine_create(test_multi_fair_mutex_entry, NULL);
+        aio_co_schedule(ctx[i], co1);
+    }
+
+    g_usleep(seconds * 1000000);
+
+    atomic_mb_set(&now_stopping, true);
+    while (running > 0) {
+        g_usleep(100000);
+    }
+
+    join_aio_contexts();
+    g_test_message("%d iterations/second\n", counter / seconds);
+    g_assert_cmpint(counter, ==, atomic_counter);
+}
+
+static void test_multi_fair_mutex_1(void)
+{
+    test_multi_fair_mutex(NUM_CONTEXTS, 1);
+}
+
+static void test_multi_fair_mutex_10(void)
+{
+    test_multi_fair_mutex(NUM_CONTEXTS, 10);
+}
+#endif
+
+/* Same test with pthread mutexes, for performance comparison and
+ * portability.  */
+
+static QemuMutex mutex;
+
+static void test_multi_mutex_entry(void *opaque)
+{
+    while (!atomic_mb_read(&now_stopping)) {
+        qemu_mutex_lock(&mutex);
+        counter++;
+        qemu_mutex_unlock(&mutex);
+        atomic_inc(&atomic_counter);
+    }
+    atomic_dec(&running);
+}
+
+static void test_multi_mutex(int threads, int seconds)
+{
+    int i;
+
+    qemu_mutex_init(&mutex);
+    counter = 0;
+    atomic_counter = 0;
+    now_stopping = false;
+
+    create_aio_contexts();
+    assert(threads <= NUM_CONTEXTS);
+    running = threads;
+    for (i = 0; i < threads; i++) {
+        Coroutine *co1 = qemu_coroutine_create(test_multi_mutex_entry, NULL);
+        aio_co_schedule(ctx[i], co1);
+    }
+
+    g_usleep(seconds * 1000000);
+
+    atomic_mb_set(&now_stopping, true);
+    while (running > 0) {
+        g_usleep(100000);
+    }
+
+    join_aio_contexts();
+    g_test_message("%d iterations/second\n", counter / seconds);
+    g_assert_cmpint(counter, ==, atomic_counter);
+}
+
+static void test_multi_mutex_1(void)
+{
+    test_multi_mutex(NUM_CONTEXTS, 1);
+}
+
+static void test_multi_mutex_10(void)
+{
+    test_multi_mutex(NUM_CONTEXTS, 10);
+}
+
 /* End of tests.  */
 
 int main(int argc, char **argv)
@@ -XXX,XX +XXX,XX @@ int main(int argc, char **argv)
         g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_1);
         g_test_add_func("/aio/multi/mutex/contended", test_multi_co_mutex_1);
         g_test_add_func("/aio/multi/mutex/handoff", test_multi_co_mutex_2_3);
+#ifdef CONFIG_LINUX
+        g_test_add_func("/aio/multi/mutex/mcs", test_multi_fair_mutex_1);
+#endif
+        g_test_add_func("/aio/multi/mutex/pthread", test_multi_mutex_1);
     } else {
         g_test_add_func("/aio/multi/schedule", test_multi_co_schedule_10);
         g_test_add_func("/aio/multi/mutex/contended", test_multi_co_mutex_10);
         g_test_add_func("/aio/multi/mutex/handoff", test_multi_co_mutex_2_30);
+#ifdef CONFIG_LINUX
+        g_test_add_func("/aio/multi/mutex/mcs", test_multi_fair_mutex_10);
+#endif
+        g_test_add_func("/aio/multi/mutex/pthread", test_multi_mutex_10);
     }
     return g_test_run();
 }
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

This will avoid forward references in the next patch.  It is also
more logical because CoQueue is not anymore the basic primitive.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213181244.16297-5-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/qemu/coroutine.h | 89 ++++++++++++++++++++++++------------------------
 1 file changed, 44 insertions(+), 45 deletions(-)

diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -XXX,XX +XXX,XX @@ bool qemu_in_coroutine(void);
  */
 bool qemu_coroutine_entered(Coroutine *co);
 
-
-/**
- * CoQueues are a mechanism to queue coroutines in order to continue executing
- * them later. They provide the fundamental primitives on which coroutine locks
- * are built.
- */
-typedef struct CoQueue {
-    QSIMPLEQ_HEAD(, Coroutine) entries;
-} CoQueue;
-
-/**
- * Initialise a CoQueue. This must be called before any other operation is used
- * on the CoQueue.
- */
-void qemu_co_queue_init(CoQueue *queue);
-
-/**
- * Adds the current coroutine to the CoQueue and transfers control to the
- * caller of the coroutine.
- */
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue);
-
-/**
- * Restarts the next coroutine in the CoQueue and removes it from the queue.
- *
- * Returns true if a coroutine was restarted, false if the queue is empty.
- */
-bool coroutine_fn qemu_co_queue_next(CoQueue *queue);
-
-/**
- * Restarts all coroutines in the CoQueue and leaves the queue empty.
- */
-void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue);
-
-/**
- * Enter the next coroutine in the queue
- */
-bool qemu_co_enter_next(CoQueue *queue);
-
-/**
- * Checks if the CoQueue is empty.
- */
-bool qemu_co_queue_empty(CoQueue *queue);
-
-
 /**
  * Provides a mutex that can be used to synchronise coroutines
  */
@@ -XXX,XX +XXX,XX @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex);
  */
 void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
 
+
+/**
+ * CoQueues are a mechanism to queue coroutines in order to continue executing
+ * them later.
+ */
+typedef struct CoQueue {
+    QSIMPLEQ_HEAD(, Coroutine) entries;
+} CoQueue;
+
+/**
+ * Initialise a CoQueue. This must be called before any other operation is used
+ * on the CoQueue.
+ */
+void qemu_co_queue_init(CoQueue *queue);
+
+/**
+ * Adds the current coroutine to the CoQueue and transfers control to the
+ * caller of the coroutine.
+ */
+void coroutine_fn qemu_co_queue_wait(CoQueue *queue);
+
+/**
+ * Restarts the next coroutine in the CoQueue and removes it from the queue.
+ *
+ * Returns true if a coroutine was restarted, false if the queue is empty.
+ */
+bool coroutine_fn qemu_co_queue_next(CoQueue *queue);
+
+/**
+ * Restarts all coroutines in the CoQueue and leaves the queue empty.
+ */
+void coroutine_fn qemu_co_queue_restart_all(CoQueue *queue);
+
+/**
+ * Enter the next coroutine in the queue
+ */
+bool qemu_co_enter_next(CoQueue *queue);
+
+/**
+ * Checks if the CoQueue is empty.
+ */
+bool qemu_co_queue_empty(CoQueue *queue);
+
+
 typedef struct CoRwlock {
     bool writer;
     int reader;
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

All that CoQueue needs in order to become thread-safe is help
from an external mutex.  Add this to the API.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213181244.16297-6-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/qemu/coroutine.h   |  8 +++++---
 block/backup.c             |  2 +-
 block/io.c                 |  4 ++--
 block/nbd-client.c         |  2 +-
 block/qcow2-cluster.c      |  4 +---
 block/sheepdog.c           |  2 +-
 block/throttle-groups.c    |  2 +-
 hw/9pfs/9p.c               |  2 +-
 util/qemu-coroutine-lock.c | 24 +++++++++++++++++++++---
 9 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -XXX,XX +XXX,XX @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex);
 
 /**
  * CoQueues are a mechanism to queue coroutines in order to continue executing
- * them later.
+ * them later.  They are similar to condition variables, but they need help
+ * from an external mutex in order to maintain thread-safety.
  */
 typedef struct CoQueue {
     QSIMPLEQ_HEAD(, Coroutine) entries;
@@ -XXX,XX +XXX,XX @@ void qemu_co_queue_init(CoQueue *queue);
 
 /**
  * Adds the current coroutine to the CoQueue and transfers control to the
- * caller of the coroutine.
+ * caller of the coroutine.  The mutex is unlocked during the wait and
+ * locked again afterwards.
  */
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue);
+void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex);
 
 /**
  * Restarts the next coroutine in the CoQueue and removes it from the queue.
diff --git a/block/backup.c b/block/backup.c
index XXXXXXX..XXXXXXX 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn wait_for_overlapping_requests(BackupBlockJob *job,
         retry = false;
         QLIST_FOREACH(req, &job->inflight_reqs, list) {
             if (end > req->start && start < req->end) {
-                qemu_co_queue_wait(&req->wait_queue);
+                qemu_co_queue_wait(&req->wait_queue, NULL);
                 retry = true;
                 break;
             }
diff --git a/block/io.c b/block/io.c
index XXXXXXX..XXXXXXX 100644
--- a/block/io.c
+++ b/block/io.c
@@ -XXX,XX +XXX,XX @@ static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self)
                  * (instead of producing a deadlock in the former case). */
                 if (!req->waiting_for) {
                     self->waiting_for = req;
-                    qemu_co_queue_wait(&req->wait_queue);
+                    qemu_co_queue_wait(&req->wait_queue, NULL);
                     self->waiting_for = NULL;
                     retry = true;
                     waited = true;
@@ -XXX,XX +XXX,XX @@ int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
 
     /* Wait until any previous flushes are completed */
     while (bs->active_flush_req) {
-        qemu_co_queue_wait(&bs->flush_queue);
+        qemu_co_queue_wait(&bs->flush_queue, NULL);
     }
 
     bs->active_flush_req = true;
diff --git a/block/nbd-client.c b/block/nbd-client.c
index XXXXXXX..XXXXXXX 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -XXX,XX +XXX,XX @@ static void nbd_coroutine_start(NBDClientSession *s,
     /* Poor man semaphore.  The free_sema is locked when no other request
      * can be accepted, and unlocked after receiving one reply.  */
     if (s->in_flight == MAX_NBD_REQUESTS) {
-        qemu_co_queue_wait(&s->free_sema);
+        qemu_co_queue_wait(&s->free_sema, NULL);
         assert(s->in_flight < MAX_NBD_REQUESTS);
     }
     s->in_flight++;
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index XXXXXXX..XXXXXXX 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -XXX,XX +XXX,XX @@ static int handle_dependencies(BlockDriverState *bs, uint64_t guest_offset,
             if (bytes == 0) {
                 /* Wait for the dependency to complete. We need to recheck
                  * the free/allocated clusters when we continue. */
-                qemu_co_mutex_unlock(&s->lock);
-                qemu_co_queue_wait(&old_alloc->dependent_requests);
-                qemu_co_mutex_lock(&s->lock);
+                qemu_co_queue_wait(&old_alloc->dependent_requests, &s->lock);
                 return -EAGAIN;
             }
         }
diff --git a/block/sheepdog.c b/block/sheepdog.c
index XXXXXXX..XXXXXXX 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -XXX,XX +XXX,XX @@ static void wait_for_overlapping_aiocb(BDRVSheepdogState *s, SheepdogAIOCB *acb)
 retry:
     QLIST_FOREACH(cb, &s->inflight_aiocb_head, aiocb_siblings) {
         if (AIOCBOverlapping(acb, cb)) {
-            qemu_co_queue_wait(&s->overlapping_queue);
+            qemu_co_queue_wait(&s->overlapping_queue, NULL);
             goto retry;
         }
     }
diff --git a/block/throttle-groups.c b/block/throttle-groups.c
index XXXXXXX..XXXXXXX 100644
--- a/block/throttle-groups.c
+++ b/block/throttle-groups.c
@@ -XXX,XX +XXX,XX @@ void coroutine_fn throttle_group_co_io_limits_intercept(BlockBackend *blk,
     if (must_wait || blkp->pending_reqs[is_write]) {
         blkp->pending_reqs[is_write]++;
         qemu_mutex_unlock(&tg->lock);
-        qemu_co_queue_wait(&blkp->throttled_reqs[is_write]);
+        qemu_co_queue_wait(&blkp->throttled_reqs[is_write], NULL);
         qemu_mutex_lock(&tg->lock);
         blkp->pending_reqs[is_write]--;
     }
diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index XXXXXXX..XXXXXXX 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn v9fs_flush(void *opaque)
         /*
          * Wait for pdu to complete.
          */
-        qemu_co_queue_wait(&cancel_pdu->complete);
+        qemu_co_queue_wait(&cancel_pdu->complete, NULL);
         cancel_pdu->cancelled = 0;
         pdu_free(cancel_pdu);
     }
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index XXXXXXX..XXXXXXX 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -XXX,XX +XXX,XX @@ void qemu_co_queue_init(CoQueue *queue)
     QSIMPLEQ_INIT(&queue->entries);
 }
 
-void coroutine_fn qemu_co_queue_wait(CoQueue *queue)
+void coroutine_fn qemu_co_queue_wait(CoQueue *queue, CoMutex *mutex)
 {
     Coroutine *self = qemu_coroutine_self();
     QSIMPLEQ_INSERT_TAIL(&queue->entries, self, co_queue_next);
+
+    if (mutex) {
+        qemu_co_mutex_unlock(mutex);
+    }
+
+    /* There is no race condition here.  Other threads will call
+     * aio_co_schedule on our AioContext, which can reenter this
+     * coroutine but only after this yield and after the main loop
+     * has gone through the next iteration.
+     */
     qemu_coroutine_yield();
     assert(qemu_in_coroutine());
+
+    /* TODO: OSv implements wait morphing here, where the wakeup
+     * primitive automatically places the woken coroutine on the
+     * mutex's queue.  This avoids the thundering herd effect.
+     */
+    if (mutex) {
+        qemu_co_mutex_lock(mutex);
+    }
 }
 
 /**
@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_rdlock(CoRwlock *lock)
     Coroutine *self = qemu_coroutine_self();
 
     while (lock->writer) {
-        qemu_co_queue_wait(&lock->queue);
+        qemu_co_queue_wait(&lock->queue, NULL);
     }
     lock->reader++;
     self->locks_held++;
@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_wrlock(CoRwlock *lock)
     Coroutine *self = qemu_coroutine_self();
 
     while (lock->writer || lock->reader) {
-        qemu_co_queue_wait(&lock->queue);
+        qemu_co_queue_wait(&lock->queue, NULL);
     }
     lock->writer = true;
     self->locks_held++;
-- 
2.9.3

From: Paolo Bonzini <pbonzini@redhat.com>

This adds a CoMutex around the existing CoQueue.  Because the write-side
can just take CoMutex, the old "writer" field is not necessary anymore.
Instead of removing it altogether, count the number of pending writers
during a read-side critical section and forbid further readers from
entering.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Message-id: 20170213181244.16297-7-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 include/qemu/coroutine.h   |  3 ++-
 util/qemu-coroutine-lock.c | 35 ++++++++++++++++++++++++-----------
 2 files changed, 26 insertions(+), 12 deletions(-)

diff --git a/include/qemu/coroutine.h b/include/qemu/coroutine.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/coroutine.h
+++ b/include/qemu/coroutine.h
@@ -XXX,XX +XXX,XX @@ bool qemu_co_queue_empty(CoQueue *queue);
 
 
 typedef struct CoRwlock {
-    bool writer;
+    int pending_writer;
     int reader;
+    CoMutex mutex;
     CoQueue queue;
 } CoRwlock;
 
diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index XXXXXXX..XXXXXXX 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_init(CoRwlock *lock)
 {
     memset(lock, 0, sizeof(*lock));
     qemu_co_queue_init(&lock->queue);
+    qemu_co_mutex_init(&lock->mutex);
 }
 
 void qemu_co_rwlock_rdlock(CoRwlock *lock)
 {
     Coroutine *self = qemu_coroutine_self();
 
-    while (lock->writer) {
-        qemu_co_queue_wait(&lock->queue, NULL);
+    qemu_co_mutex_lock(&lock->mutex);
+    /* For fairness, wait if a writer is in line.  */
+    while (lock->pending_writer) {
+        qemu_co_queue_wait(&lock->queue, &lock->mutex);
     }
     lock->reader++;
+    qemu_co_mutex_unlock(&lock->mutex);
+
+    /* The rest of the read-side critical section is run without the mutex.  */
     self->locks_held++;
 }
 
@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_unlock(CoRwlock *lock)
     Coroutine *self = qemu_coroutine_self();
 
     assert(qemu_in_coroutine());
-    if (lock->writer) {
-        lock->writer = false;
+    if (!lock->reader) {
+        /* The critical section started in qemu_co_rwlock_wrlock.  */
         qemu_co_queue_restart_all(&lock->queue);
     } else {
+        self->locks_held--;
+
+        qemu_co_mutex_lock(&lock->mutex);
         lock->reader--;
         assert(lock->reader >= 0);
         /* Wakeup only one waiting writer */
@@ -XXX,XX +XXX,XX @@ void qemu_co_rwlock_unlock(CoRwlock *lock)
             qemu_co_queue_next(&lock->queue);
         }
     }
-    self->locks_held--;
+    qemu_co_mutex_unlock(&lock->mutex);
 }
 
 void qemu_co_rwlock_wrlock(CoRwlock *lock)
 {
-    Coroutine *self = qemu_coroutine_self();
-
-    while (lock->writer || lock->reader) {
-        qemu_co_queue_wait(&lock->queue, NULL);
+    qemu_co_mutex_lock(&lock->mutex);
+    lock->pending_writer++;
+    while (lock->reader) {
+        qemu_co_queue_wait(&lock->queue, &lock->mutex);
     }
-    lock->writer = true;
-    self->locks_held++;
+    lock->pending_writer--;
+
+    /* The rest of the write-side critical section is run with
+     * the mutex taken, so that lock->reader remains zero.
+     * There is no need to update self->locks_held.
+     */
 }
-- 
2.9.3

The following changes since commit 19b599f7664b2ebfd0f405fb79c14dd241557452:

Merge remote-tracking branch 'remotes/armbru/tags/pull-error-2018-08-27-v2' into staging (2018-08-27 16:44:20 +0100)

are available in the Git repository at:

https://git.xanclic.moe/XanClic/qemu.git tags/pull-block-2018-08-31-v2

for you to fetch changes up to e21a1c9831fc80ae3f3c1affdfa43350035d8588:

jobs: remove job_defer_to_main_loop (2018-08-31 16:28:33 +0200)

----------------------------------------------------------------
Block patches:
- (Block) job exit refactoring, part 1
  (removing job_defer_to_main_loop())
- test-bdrv-drain leak fix

----------------------------------------------------------------
John Snow (9):
  jobs: change start callback to run callback
  jobs: canonize Error object
  jobs: add exit shim
  block/commit: utilize job_exit shim
  block/mirror: utilize job_exit shim
  jobs: utilize job_exit shim
  block/backup: make function variables consistently named
  jobs: remove ret argument to job_completed; privatize it
  jobs: remove job_defer_to_main_loop

Marc-André Lureau (1):
  tests: fix bdrv-drain leak

-- 
2.17.1

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Spotted by ASAN:

=================================================================
==5378==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 65536 byte(s) in 1 object(s) allocated from:
    #0 0x7f788f83bc48 in malloc (/lib64/libasan.so.5+0xeec48)
    #1 0x7f788c9923c5 in g_malloc (/lib64/libglib-2.0.so.0+0x523c5)
    #2 0x5622a1fe37bc in coroutine_trampoline /home/elmarco/src/qq/util/coroutine-ucontext.c:116
    #3 0x7f788a15d75f in __correctly_grouped_prefixwc (/lib64/libc.so.6+0x4c75f)

(Broken in commit 4c8158e359d.)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20180809114417.28718-3-marcandre.lureau@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 tests/test-bdrv-drain.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn test_co_delete_by_drain(void *opaque)
     }
 
     dbdd->done = true;
+    g_free(buffer);
 }
 
 /**
-- 
2.17.1

From: John Snow <jsnow@redhat.com>

Presently we codify the entry point for a job as the "start" callback,
but a more apt name would be "run" to clarify the idea that when this
function returns we consider the job to have "finished," except for
any cleanup which occurs in separate callbacks later.

As part of this clarification, change the signature to include an error
object and a return code. The error ptr is not yet used, and the return
code while captured, will be overwritten by actions in the job_completed
function.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180830015734.19765-2-jsnow@redhat.com
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/qemu/job.h        |  2 +-
 block/backup.c            |  7 ++++---
 block/commit.c            |  7 ++++---
 block/create.c            |  8 +++++---
 block/mirror.c            | 10 ++++++----
 block/stream.c            |  7 ++++---
 job.c                     |  6 +++---
 tests/test-bdrv-drain.c   |  7 ++++---
 tests/test-blockjob-txn.c | 16 ++++++++--------
 tests/test-blockjob.c     |  7 ++++---
 10 files changed, 43 insertions(+), 34 deletions(-)

diff --git a/include/qemu/job.h b/include/qemu/job.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -XXX,XX +XXX,XX @@ struct JobDriver {
     JobType job_type;
 
     /** Mandatory: Entrypoint for the Coroutine. */
-    CoroutineEntry *start;
+    int coroutine_fn (*run)(Job *job, Error **errp);
 
     /**
      * If the callback is not NULL, it will be invoked when the job transitions
diff --git a/block/backup.c b/block/backup.c
index XXXXXXX..XXXXXXX 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -XXX,XX +XXX,XX @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
     bdrv_dirty_iter_free(dbi);
 }
 
-static void coroutine_fn backup_run(void *opaque)
+static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
 {
-    BackupBlockJob *job = opaque;
+    BackupBlockJob *job = container_of(opaque_job, BackupBlockJob, common.job);
     BackupCompleteData *data;
     BlockDriverState *bs = blk_bs(job->common.blk);
     int64_t offset, nb_clusters;
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn backup_run(void *opaque)
     data = g_malloc(sizeof(*data));
     data->ret = ret;
     job_defer_to_main_loop(&job->common.job, backup_complete, data);
+    return ret;
 }
 
 static const BlockJobDriver backup_job_driver = {
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver backup_job_driver = {
         .free                   = block_job_free,
         .user_resume            = block_job_user_resume,
         .drain                  = block_job_drain,
-        .start                  = backup_run,
+        .run                    = backup_run,
         .commit                 = backup_commit,
         .abort                  = backup_abort,
         .clean                  = backup_clean,
diff --git a/block/commit.c b/block/commit.c
index XXXXXXX..XXXXXXX 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
     bdrv_unref(top);
 }
 
-static void coroutine_fn commit_run(void *opaque)
+static int coroutine_fn commit_run(Job *job, Error **errp)
 {
-    CommitBlockJob *s = opaque;
+    CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
     CommitCompleteData *data;
     int64_t offset;
     uint64_t delay_ns = 0;
@@ -XXX,XX +XXX,XX @@ out:
     data = g_malloc(sizeof(*data));
     data->ret = ret;
     job_defer_to_main_loop(&s->common.job, commit_complete, data);
+    return ret;
 }
 
 static const BlockJobDriver commit_job_driver = {
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_job_driver = {
         .free          = block_job_free,
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
-        .start         = commit_run,
+        .run           = commit_run,
     },
 };
 
diff --git a/block/create.c b/block/create.c
index XXXXXXX..XXXXXXX 100644
--- a/block/create.c
+++ b/block/create.c
@@ -XXX,XX +XXX,XX @@ static void blockdev_create_complete(Job *job, void *opaque)
     job_completed(job, s->ret, s->err);
 }
 
-static void coroutine_fn blockdev_create_run(void *opaque)
+static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
 {
-    BlockdevCreateJob *s = opaque;
+    BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
 
     job_progress_set_remaining(&s->common, 1);
     s->ret = s->drv->bdrv_co_create(s->opts, &s->err);
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn blockdev_create_run(void *opaque)
 
     qapi_free_BlockdevCreateOptions(s->opts);
     job_defer_to_main_loop(&s->common, blockdev_create_complete, NULL);
+
+    return s->ret;
 }
 
 static const JobDriver blockdev_create_job_driver = {
     .instance_size = sizeof(BlockdevCreateJob),
     .job_type      = JOB_TYPE_CREATE,
-    .start         = blockdev_create_run,
+    .run           = blockdev_create_run,
 };
 
 void qmp_blockdev_create(const char *job_id, BlockdevCreateOptions *options,
diff --git a/block/mirror.c b/block/mirror.c
index XXXXXXX..XXXXXXX 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -XXX,XX +XXX,XX @@ static int mirror_flush(MirrorBlockJob *s)
     return ret;
 }
 
-static void coroutine_fn mirror_run(void *opaque)
+static int coroutine_fn mirror_run(Job *job, Error **errp)
 {
-    MirrorBlockJob *s = opaque;
+    MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
     MirrorExitData *data;
     BlockDriverState *bs = s->mirror_top_bs->backing->bs;
     BlockDriverState *target_bs = blk_bs(s->target);
@@ -XXX,XX +XXX,XX @@ immediate_exit:
     if (need_drain) {
         bdrv_drained_begin(bs);
     }
+
     job_defer_to_main_loop(&s->common.job, mirror_exit, data);
+    return ret;
 }
 
 static void mirror_complete(Job *job, Error **errp)
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver mirror_job_driver = {
         .free                   = block_job_free,
         .user_resume            = block_job_user_resume,
         .drain                  = block_job_drain,
-        .start                  = mirror_run,
+        .run                    = mirror_run,
         .pause                  = mirror_pause,
         .complete               = mirror_complete,
     },
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_active_job_driver = {
         .free                   = block_job_free,
         .user_resume            = block_job_user_resume,
         .drain                  = block_job_drain,
-        .start                  = mirror_run,
+        .run                    = mirror_run,
         .pause                  = mirror_pause,
         .complete               = mirror_complete,
     },
diff --git a/block/stream.c b/block/stream.c
index XXXXXXX..XXXXXXX 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@ out:
     g_free(data);
 }
 
-static void coroutine_fn stream_run(void *opaque)
+static int coroutine_fn stream_run(Job *job, Error **errp)
 {
-    StreamBlockJob *s = opaque;
+    StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
     StreamCompleteData *data;
     BlockBackend *blk = s->common.blk;
     BlockDriverState *bs = blk_bs(blk);
@@ -XXX,XX +XXX,XX @@ out:
     data = g_malloc(sizeof(*data));
     data->ret = ret;
     job_defer_to_main_loop(&s->common.job, stream_complete, data);
+    return ret;
 }
 
 static const BlockJobDriver stream_job_driver = {
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver stream_job_driver = {
         .instance_size = sizeof(StreamBlockJob),
         .job_type      = JOB_TYPE_STREAM,
         .free          = block_job_free,
-        .start         = stream_run,
+        .run           = stream_run,
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
     },
diff --git a/job.c b/job.c
index XXXXXXX..XXXXXXX 100644
--- a/job.c
+++ b/job.c
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)
 {
     Job *job = opaque;
 
-    assert(job && job->driver && job->driver->start);
+    assert(job && job->driver && job->driver->run);
     job_pause_point(job);
-    job->driver->start(job);
+    job->ret = job->driver->run(job, NULL);
 }
 
 
 void job_start(Job *job)
 {
     assert(job && !job_started(job) && job->paused &&
-           job->driver && job->driver->start);
+           job->driver && job->driver->run);
     job->co = qemu_coroutine_create(job_co_entry, job);
     job->pause_count--;
     job->busy = true;
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -XXX,XX +XXX,XX @@ static void test_job_completed(Job *job, void *opaque)
     job_completed(job, 0, NULL);
 }
 
-static void coroutine_fn test_job_start(void *opaque)
+static int coroutine_fn test_job_run(Job *job, Error **errp)
 {
-    TestBlockJob *s = opaque;
+    TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 
     job_transition_to_ready(&s->common.job);
     while (!s->should_complete) {
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn test_job_start(void *opaque)
     }
 
     job_defer_to_main_loop(&s->common.job, test_job_completed, NULL);
+    return 0;
 }
 
 static void test_job_complete(Job *job, Error **errp)
@@ -XXX,XX +XXX,XX @@ BlockJobDriver test_job_driver = {
         .free           = block_job_free,
         .user_resume    = block_job_user_resume,
         .drain          = block_job_drain,
-        .start          = test_job_start,
+        .run            = test_job_run,
         .complete       = test_job_complete,
     },
 };
diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-blockjob-txn.c
+++ b/tests/test-blockjob-txn.c
@@ -XXX,XX +XXX,XX @@ static void test_block_job_complete(Job *job, void *opaque)
     bdrv_unref(bs);
 }
 
-static void coroutine_fn test_block_job_run(void *opaque)
+static int coroutine_fn test_block_job_run(Job *job, Error **errp)
 {
-    TestBlockJob *s = opaque;
-    BlockJob *job = &s->common;
+    TestBlockJob *s = container_of(job, TestBlockJob, common.job);
 
     while (s->iterations--) {
         if (s->use_timer) {
-            job_sleep_ns(&job->job, 0);
+            job_sleep_ns(job, 0);
         } else {
-            job_yield(&job->job);
+            job_yield(job);
         }
 
-        if (job_is_cancelled(&job->job)) {
+        if (job_is_cancelled(job)) {
             break;
         }
     }
 
-    job_defer_to_main_loop(&job->job, test_block_job_complete,
+    job_defer_to_main_loop(job, test_block_job_complete,
                            (void *)(intptr_t)s->rc);
+    return s->rc;
 }
 
 typedef struct {
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_block_job_driver = {
         .free          = block_job_free,
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
-        .start         = test_block_job_run,
+        .run           = test_block_job_run,
     },
 };
 
diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-blockjob.c
+++ b/tests/test-blockjob.c
@@ -XXX,XX +XXX,XX @@ static void cancel_job_complete(Job *job, Error **errp)
     s->should_complete = true;
 }
 
-static void coroutine_fn cancel_job_start(void *opaque)
+static int coroutine_fn cancel_job_run(Job *job, Error **errp)
 {
-    CancelJob *s = opaque;
+    CancelJob *s = container_of(job, CancelJob, common.job);
 
     while (!s->should_complete) {
         if (job_is_cancelled(&s->common.job)) {
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn cancel_job_start(void *opaque)
 
  defer:
     job_defer_to_main_loop(&s->common.job, cancel_job_completed, s);
+    return 0;
 }
 
 static const BlockJobDriver test_cancel_driver = {
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_cancel_driver = {
         .free          = block_job_free,
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
-        .start         = cancel_job_start,
+        .run           = cancel_job_run,
         .complete      = cancel_job_complete,
     },
 };
-- 
2.17.1

From: John Snow <jsnow@redhat.com>

Jobs presently use both an Error object in the case of the create job,
and char strings in the case of generic errors elsewhere.

Unify the two paths as just j->err, and remove the extra argument from
job_completed. The integer error code for job_completed is kept for now,
to be removed shortly in a separate patch.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20180830015734.19765-3-jsnow@redhat.com
[mreitz: Dropped a superfluous g_strdup()]
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/qemu/job.h        | 14 ++++++++------
 block/backup.c            |  2 +-
 block/commit.c            |  2 +-
 block/create.c            |  5 ++---
 block/mirror.c            |  2 +-
 block/stream.c            |  2 +-
 job-qmp.c                 |  5 +++--
 job.c                     | 18 ++++++------------
 tests/test-bdrv-drain.c   |  2 +-
 tests/test-blockjob-txn.c |  2 +-
 tests/test-blockjob.c     |  2 +-
 11 files changed, 26 insertions(+), 30 deletions(-)

diff --git a/include/qemu/job.h b/include/qemu/job.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -XXX,XX +XXX,XX @@ typedef struct Job {
     /** Estimated progress_current value at the completion of the job */
     int64_t progress_total;
 
-    /** Error string for a failed job (NULL if, and only if, job->ret == 0) */
-    char *error;
-
     /** ret code passed to job_completed. */
     int ret;
 
+    /**
+     * Error object for a failed job.
+     * If job->ret is nonzero and an error object was not set, it will be set
+     * to strerror(-job->ret) during job_completed.
+     */
+    Error *err;
+
     /** The completion function that will be called when the job completes.  */
     BlockCompletionFunc *cb;
 
@@ -XXX,XX +XXX,XX @@ void job_transition_to_ready(Job *job);
 /**
  * @job: The job being completed.
  * @ret: The status code.
- * @error: The error message for a failing job (only with @ret < 0). If @ret is
- *         negative, but NULL is given for @error, strerror() is used.
  *
  * Marks @job as completed. If @ret is non-zero, the job transaction it is part
  * of is aborted. If @ret is zero, the job moves into the WAITING state. If it
  * is the last job to complete in its transaction, all jobs in the transaction
  * move from WAITING to PENDING.
  */
-void job_completed(Job *job, int ret, Error *error);
+void job_completed(Job *job, int ret);
 
 /** Asynchronously complete the specified @job. */
 void job_complete(Job *job, Error **errp);
diff --git a/block/backup.c b/block/backup.c
index XXXXXXX..XXXXXXX 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -XXX,XX +XXX,XX @@ static void backup_complete(Job *job, void *opaque)
 {
     BackupCompleteData *data = opaque;
 
-    job_completed(job, data->ret, NULL);
+    job_completed(job, data->ret);
     g_free(data);
 }
 
diff --git a/block/commit.c b/block/commit.c
index XXXXXXX..XXXXXXX 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
      * bdrv_set_backing_hd() to fail. */
     block_job_remove_all_bdrv(bjob);
 
-    job_completed(job, ret, NULL);
+    job_completed(job, ret);
     g_free(data);
 
     /* If bdrv_drop_intermediate() didn't already do that, remove the commit
diff --git a/block/create.c b/block/create.c
index XXXXXXX..XXXXXXX 100644
--- a/block/create.c
+++ b/block/create.c
@@ -XXX,XX +XXX,XX @@ typedef struct BlockdevCreateJob {
     BlockDriver *drv;
     BlockdevCreateOptions *opts;
     int ret;
-    Error *err;
 } BlockdevCreateJob;
 
 static void blockdev_create_complete(Job *job, void *opaque)
 {
     BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
 
-    job_completed(job, s->ret, s->err);
+    job_completed(job, s->ret);
 }
 
 static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
     BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
 
     job_progress_set_remaining(&s->common, 1);
-    s->ret = s->drv->bdrv_co_create(s->opts, &s->err);
+    s->ret = s->drv->bdrv_co_create(s->opts, errp);
     job_progress_update(&s->common, 1);
 
     qapi_free_BlockdevCreateOptions(s->opts);
diff --git a/block/mirror.c b/block/mirror.c
index XXXXXXX..XXXXXXX 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
     blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort);
 
     bs_opaque->job = NULL;
-    job_completed(job, data->ret, NULL);
+    job_completed(job, data->ret);
 
     g_free(data);
     bdrv_drained_end(src);
diff --git a/block/stream.c b/block/stream.c
index XXXXXXX..XXXXXXX 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@ out:
     }
 
     g_free(s->backing_file_str);
-    job_completed(job, data->ret, NULL);
+    job_completed(job, data->ret);
     g_free(data);
 }
 
diff --git a/job-qmp.c b/job-qmp.c
index XXXXXXX..XXXXXXX 100644
--- a/job-qmp.c
+++ b/job-qmp.c
@@ -XXX,XX +XXX,XX @@ static JobInfo *job_query_single(Job *job, Error **errp)
         .status             = job->status,
         .current_progress   = job->progress_current,
         .total_progress     = job->progress_total,
-        .has_error          = !!job->error,
-        .error              = g_strdup(job->error),
+        .has_error          = !!job->err,
+        .error              = job->err ? \
+                              g_strdup(error_get_pretty(job->err)) : NULL,
     };
 
     return info;
diff --git a/job.c b/job.c
index XXXXXXX..XXXXXXX 100644
--- a/job.c
+++ b/job.c
@@ -XXX,XX +XXX,XX @@ void job_unref(Job *job)
 
         QLIST_REMOVE(job, job_list);
 
-        g_free(job->error);
+        error_free(job->err);
         g_free(job->id);
         g_free(job);
     }
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)
 
     assert(job && job->driver && job->driver->run);
     job_pause_point(job);
-    job->ret = job->driver->run(job, NULL);
+    job->ret = job->driver->run(job, &job->err);
 }
 
 
@@ -XXX,XX +XXX,XX @@ static void job_update_rc(Job *job)
         job->ret = -ECANCELED;
     }
     if (job->ret) {
-        if (!job->error) {
-            job->error = g_strdup(strerror(-job->ret));
+        if (!job->err) {
+            error_setg(&job->err, "%s", strerror(-job->ret));
         }
         job_state_transition(job, JOB_STATUS_ABORTING);
     }
@@ -XXX,XX +XXX,XX @@ static void job_completed_txn_success(Job *job)
     }
 }
 
-void job_completed(Job *job, int ret, Error *error)
+void job_completed(Job *job, int ret)
 {
     assert(job && job->txn && !job_is_completed(job));
 
     job->ret = ret;
-    if (error) {
-        assert(job->ret < 0);
-        job->error = g_strdup(error_get_pretty(error));
-        error_free(error);
-    }
-
     job_update_rc(job);
     trace_job_completed(job, ret, job->ret);
     if (job->ret) {
@@ -XXX,XX +XXX,XX @@ void job_cancel(Job *job, bool force)
     }
     job_cancel_async(job, force);
     if (!job_started(job)) {
-        job_completed(job, -ECANCELED, NULL);
+        job_completed(job, -ECANCELED);
     } else if (job->deferred_to_main_loop) {
         job_completed_txn_abort(job);
     } else {
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -XXX,XX +XXX,XX @@ typedef struct TestBlockJob {
 
 static void test_job_completed(Job *job, void *opaque)
 {
-    job_completed(job, 0, NULL);
+    job_completed(job, 0);
 }
 
 static int coroutine_fn test_job_run(Job *job, Error **errp)
diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-blockjob-txn.c
+++ b/tests/test-blockjob-txn.c
@@ -XXX,XX +XXX,XX @@ static void test_block_job_complete(Job *job, void *opaque)
         rc = -ECANCELED;
     }
 
-    job_completed(job, rc, NULL);
+    job_completed(job, rc);
     bdrv_unref(bs);
 }
 
diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-blockjob.c
+++ b/tests/test-blockjob.c
@@ -XXX,XX +XXX,XX @@ static void cancel_job_completed(Job *job, void *opaque)
 {
     CancelJob *s = opaque;
     s->completed = true;
-    job_completed(job, 0, NULL);
+    job_completed(job, 0);
 }
 
 static void cancel_job_complete(Job *job, Error **errp)
-- 
2.17.1

From: John Snow <jsnow@redhat.com>

All jobs do the same thing when they leave their running loop:
- Store the return code in a structure
- wait to receive this structure in the main thread
- signal job completion via job_completed

Few jobs do anything beyond exactly this. Consolidate this exit
logic for a net reduction in SLOC.

More seriously, when we utilize job_defer_to_main_loop_bh to call
a function that calls job_completed, job_finalize_single will run
in a context where it has recursively taken the aio_context lock,
which can cause hangs if it puts down a reference that causes a flush.

You can observe this in practice by looking at mirror_exit's careful
placement of job_completed and bdrv_unref calls.

If we centralize job exiting, we can signal job completion from outside
of the aio_context, which should allow for job cleanup code to run with
only one lock, which makes cleanup callbacks less tricky to write.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180830015734.19765-4-jsnow@redhat.com
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/qemu/job.h | 11 +++++++++++
 job.c              | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/include/qemu/job.h b/include/qemu/job.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -XXX,XX +XXX,XX @@ struct JobDriver {
      */
     void (*drain)(Job *job);
 
+    /**
+     * If the callback is not NULL, exit will be invoked from the main thread
+     * when the job's coroutine has finished, but before transactional
+     * convergence; before @prepare or @abort.
+     *
+     * FIXME TODO: This callback is only temporary to transition remaining jobs
+     * to prepare/commit/abort/clean callbacks and will be removed before 3.1.
+     * is released.
+     */
+    void (*exit)(Job *job);
+
     /**
      * If the callback is not NULL, prepare will be invoked when all the jobs
      * belonging to the same transaction complete; or upon this job's completion
diff --git a/job.c b/job.c
index XXXXXXX..XXXXXXX 100644
--- a/job.c
+++ b/job.c
@@ -XXX,XX +XXX,XX @@ void job_drain(Job *job)
     }
 }
 
+static void job_exit(void *opaque)
+{
+    Job *job = (Job *)opaque;
+    AioContext *aio_context = job->aio_context;
+
+    if (job->driver->exit) {
+        aio_context_acquire(aio_context);
+        job->driver->exit(job);
+        aio_context_release(aio_context);
+    }
+    job_completed(job, job->ret);
+}
 
 /**
  * All jobs must allow a pause point before entering their job proper. This
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)
     assert(job && job->driver && job->driver->run);
     job_pause_point(job);
     job->ret = job->driver->run(job, &job->err);
+    if (!job->deferred_to_main_loop) {
+        job->deferred_to_main_loop = true;
+        aio_bh_schedule_oneshot(qemu_get_aio_context(),
+                                job_exit,
+                                job);
+    }
 }
 
 
-- 
2.17.1

From: John Snow <jsnow@redhat.com>

Change the manual deferment to commit_complete into the implicit
callback to job_exit, renaming commit_complete to commit_exit.

This conversion does change the timing of when job_completed is
called to after the bdrv_replace_node and bdrv_unref calls, which
could have implications for bjob->blk which will now be put down
after this cleanup.

Kevin highlights that we did not take any permissions for that backend
at job creation time, so it is safe to reorder these operations.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180830015734.19765-5-jsnow@redhat.com
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/commit.c | 22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/block/commit.c b/block/commit.c
index XXXXXXX..XXXXXXX 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn commit_populate(BlockBackend *bs, BlockBackend *base,
     return 0;
 }
 
-typedef struct {
-    int ret;
-} CommitCompleteData;
-
-static void commit_complete(Job *job, void *opaque)
+static void commit_exit(Job *job)
 {
     CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
     BlockJob *bjob = &s->common;
-    CommitCompleteData *data = opaque;
     BlockDriverState *top = blk_bs(s->top);
     BlockDriverState *base = blk_bs(s->base);
     BlockDriverState *commit_top_bs = s->commit_top_bs;
-    int ret = data->ret;
     bool remove_commit_top_bs = false;
 
     /* Make sure commit_top_bs and top stay around until bdrv_replace_node() */
@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
      * the normal backing chain can be restored. */
     blk_unref(s->base);
 
-    if (!job_is_cancelled(job) && ret == 0) {
+    if (!job_is_cancelled(job) && job->ret == 0) {
         /* success */
-        ret = bdrv_drop_intermediate(s->commit_top_bs, base,
-                                     s->backing_file_str);
+        job->ret = bdrv_drop_intermediate(s->commit_top_bs, base,
+                                          s->backing_file_str);
     } else {
         /* XXX Can (or should) we somehow keep 'consistent read' blocked even
          * after the failed/cancelled commit job is gone? If we already wrote
@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
      * bdrv_set_backing_hd() to fail. */
     block_job_remove_all_bdrv(bjob);
 
-    job_completed(job, ret);
-    g_free(data);
-
     /* If bdrv_drop_intermediate() didn't already do that, remove the commit
      * filter driver from the backing chain. Do this as the final step so that
      * the 'consistent read' permission can be granted.  */
@@ -XXX,XX +XXX,XX @@ static void commit_complete(Job *job, void *opaque)
 static int coroutine_fn commit_run(Job *job, Error **errp)
 {
     CommitBlockJob *s = container_of(job, CommitBlockJob, common.job);
-    CommitCompleteData *data;
     int64_t offset;
     uint64_t delay_ns = 0;
     int ret = 0;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn commit_run(Job *job, Error **errp)
 out:
     qemu_vfree(buf);
 
-    data = g_malloc(sizeof(*data));
-    data->ret = ret;
-    job_defer_to_main_loop(&s->common.job, commit_complete, data);
     return ret;
 }
 
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_job_driver = {
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
         .run           = commit_run,
+        .exit          = commit_exit,
     },
 };
 
-- 
2.17.1

From: John Snow <jsnow@redhat.com>

Change the manual deferment to mirror_exit into the implicit
callback to job_exit and the mirror_exit callback.

This does change the order of some bdrv_unref calls and job_completed,
but thanks to the new context in which we call .exit, this is safe to
defer the possible flushing of any nodes to the job_finalize_single
cleanup stage.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20180830015734.19765-6-jsnow@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/mirror.c | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/block/mirror.c b/block/mirror.c
index XXXXXXX..XXXXXXX 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -XXX,XX +XXX,XX @@ static void mirror_wait_for_all_io(MirrorBlockJob *s)
     }
 }
 
-typedef struct {
-    int ret;
-} MirrorExitData;
-
-static void mirror_exit(Job *job, void *opaque)
+static void mirror_exit(Job *job)
 {
     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
     BlockJob *bjob = &s->common;
-    MirrorExitData *data = opaque;
     MirrorBDSOpaque *bs_opaque = s->mirror_top_bs->opaque;
     AioContext *replace_aio_context = NULL;
     BlockDriverState *src = s->mirror_top_bs->backing->bs;
     BlockDriverState *target_bs = blk_bs(s->target);
     BlockDriverState *mirror_top_bs = s->mirror_top_bs;
     Error *local_err = NULL;
+    int ret = job->ret;
 
     bdrv_release_dirty_bitmap(src, s->dirty_bitmap);
 
-    /* Make sure that the source BDS doesn't go away before we called
-     * job_completed(). */
+    /* Make sure that the source BDS doesn't go away during bdrv_replace_node,
+     * before we can call bdrv_drained_end */
     bdrv_ref(src);
     bdrv_ref(mirror_top_bs);
     bdrv_ref(target_bs);
@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
             bdrv_set_backing_hd(target_bs, backing, &local_err);
             if (local_err) {
                 error_report_err(local_err);
-                data->ret = -EPERM;
+                ret = -EPERM;
             }
         }
     }
@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
         aio_context_acquire(replace_aio_context);
     }
 
-    if (s->should_complete && data->ret == 0) {
+    if (s->should_complete && ret == 0) {
         BlockDriverState *to_replace = src;
         if (s->to_replace) {
             to_replace = s->to_replace;
@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
         bdrv_drained_end(target_bs);
         if (local_err) {
             error_report_err(local_err);
-            data->ret = -EPERM;
+            ret = -EPERM;
         }
     }
     if (s->to_replace) {
@@ -XXX,XX +XXX,XX @@ static void mirror_exit(Job *job, void *opaque)
     blk_insert_bs(bjob->blk, mirror_top_bs, &error_abort);
 
     bs_opaque->job = NULL;
-    job_completed(job, data->ret);
 
-    g_free(data);
     bdrv_drained_end(src);
     bdrv_unref(mirror_top_bs);
     bdrv_unref(src);
+
+    job->ret = ret;
 }
 
 static void mirror_throttle(MirrorBlockJob *s)
@@ -XXX,XX +XXX,XX @@ static int mirror_flush(MirrorBlockJob *s)
 static int coroutine_fn mirror_run(Job *job, Error **errp)
 {
     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
-    MirrorExitData *data;
     BlockDriverState *bs = s->mirror_top_bs->backing->bs;
     BlockDriverState *target_bs = blk_bs(s->target);
     bool need_drain = true;
@@ -XXX,XX +XXX,XX @@ immediate_exit:
     g_free(s->in_flight_bitmap);
     bdrv_dirty_iter_free(s->dbi);
 
-    data = g_malloc(sizeof(*data));
-    data->ret = ret;
-
     if (need_drain) {
         bdrv_drained_begin(bs);
     }
 
-    job_defer_to_main_loop(&s->common.job, mirror_exit, data);
     return ret;
 }
 
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver mirror_job_driver = {
         .user_resume            = block_job_user_resume,
         .drain                  = block_job_drain,
         .run                    = mirror_run,
+        .exit                   = mirror_exit,
         .pause                  = mirror_pause,
         .complete               = mirror_complete,
     },
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver commit_active_job_driver = {
         .user_resume            = block_job_user_resume,
         .drain                  = block_job_drain,
         .run                    = mirror_run,
+        .exit                   = mirror_exit,
         .pause                  = mirror_pause,
         .complete               = mirror_complete,
     },
-- 
2.17.1

From: John Snow <jsnow@redhat.com>

Utilize the job_exit shim by not calling job_defer_to_main_loop, and
where applicable, converting the deferred callback into the job_exit
callback.

This converts backup, stream, create, and the unit tests all at once.
Most of these jobs do not see any changes to the order in which they
clean up their resources, except the test-blockjob-txn test, which
now puts down its bs before job_completed is called.

This is safe for the same reason the reordering in the mirror job is
safe, because job_completed no longer runs under two locks, making
the unref safe even if it causes a flush.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180830015734.19765-7-jsnow@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/backup.c            | 16 ----------------
 block/create.c            | 14 +++-----------
 block/stream.c            | 22 +++++++---------------
 tests/test-bdrv-drain.c   |  6 ------
 tests/test-blockjob-txn.c | 11 ++---------
 tests/test-blockjob.c     | 10 ++++------
 6 files changed, 16 insertions(+), 63 deletions(-)

diff --git a/block/backup.c b/block/backup.c
index XXXXXXX..XXXXXXX 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -XXX,XX +XXX,XX @@ static BlockErrorAction backup_error_action(BackupBlockJob *job,
     }
 }
 
-typedef struct {
-    int ret;
-} BackupCompleteData;
-
-static void backup_complete(Job *job, void *opaque)
-{
-    BackupCompleteData *data = opaque;
-
-    job_completed(job, data->ret);
-    g_free(data);
-}
-
 static bool coroutine_fn yield_and_check(BackupBlockJob *job)
 {
     uint64_t delay_ns;
@@ -XXX,XX +XXX,XX @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
 static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
 {
     BackupBlockJob *job = container_of(opaque_job, BackupBlockJob, common.job);
-    BackupCompleteData *data;
     BlockDriverState *bs = blk_bs(job->common.blk);
     int64_t offset, nb_clusters;
     int ret = 0;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
     qemu_co_rwlock_unlock(&job->flush_rwlock);
     hbitmap_free(job->copy_bitmap);
 
-    data = g_malloc(sizeof(*data));
-    data->ret = ret;
-    job_defer_to_main_loop(&job->common.job, backup_complete, data);
     return ret;
 }
 
diff --git a/block/create.c b/block/create.c
index XXXXXXX..XXXXXXX 100644
--- a/block/create.c
+++ b/block/create.c
@@ -XXX,XX +XXX,XX @@ typedef struct BlockdevCreateJob {
     Job common;
     BlockDriver *drv;
     BlockdevCreateOptions *opts;
-    int ret;
 } BlockdevCreateJob;
 
-static void blockdev_create_complete(Job *job, void *opaque)
-{
-    BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
-
-    job_completed(job, s->ret);
-}
-
 static int coroutine_fn blockdev_create_run(Job *job, Error **errp)
 {
     BlockdevCreateJob *s = container_of(job, BlockdevCreateJob, common);
+    int ret;
 
     job_progress_set_remaining(&s->common, 1);
-    s->ret = s->drv->bdrv_co_create(s->opts, errp);
+    ret = s->drv->bdrv_co_create(s->opts, errp);
     job_progress_update(&s->common, 1);
 
     qapi_free_BlockdevCreateOptions(s->opts);
-    job_defer_to_main_loop(&s->common, blockdev_create_complete, NULL);
 
-    return s->ret;
+    return ret;
 }
 
 static const JobDriver blockdev_create_job_driver = {
diff --git a/block/stream.c b/block/stream.c
index XXXXXXX..XXXXXXX 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_populate(BlockBackend *blk,
     return blk_co_preadv(blk, offset, qiov.size, &qiov, BDRV_REQ_COPY_ON_READ);
 }
 
-typedef struct {
-    int ret;
-} StreamCompleteData;
-
-static void stream_complete(Job *job, void *opaque)
+static void stream_exit(Job *job)
 {
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
     BlockJob *bjob = &s->common;
-    StreamCompleteData *data = opaque;
     BlockDriverState *bs = blk_bs(bjob->blk);
     BlockDriverState *base = s->base;
     Error *local_err = NULL;
+    int ret = job->ret;
 
-    if (!job_is_cancelled(job) && bs->backing && data->ret == 0) {
+    if (!job_is_cancelled(job) && bs->backing && ret == 0) {
         const char *base_id = NULL, *base_fmt = NULL;
         if (base) {
             base_id = s->backing_file_str;
@@ -XXX,XX +XXX,XX @@ static void stream_complete(Job *job, void *opaque)
                 base_fmt = base->drv->format_name;
             }
         }
-        data->ret = bdrv_change_backing_file(bs, base_id, base_fmt);
+        ret = bdrv_change_backing_file(bs, base_id, base_fmt);
         bdrv_set_backing_hd(bs, base, &local_err);
         if (local_err) {
             error_report_err(local_err);
-            data->ret = -EPERM;
+            ret = -EPERM;
             goto out;
         }
     }
@@ -XXX,XX +XXX,XX @@ out:
     }
 
     g_free(s->backing_file_str);
-    job_completed(job, data->ret);
-    g_free(data);
+    job->ret = ret;
 }
 
 static int coroutine_fn stream_run(Job *job, Error **errp)
 {
     StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
-    StreamCompleteData *data;
     BlockBackend *blk = s->common.blk;
     BlockDriverState *bs = blk_bs(blk);
     BlockDriverState *base = s->base;
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn stream_run(Job *job, Error **errp)
 
 out:
     /* Modify backing chain and close BDSes in main loop */
-    data = g_malloc(sizeof(*data));
-    data->ret = ret;
-    job_defer_to_main_loop(&s->common.job, stream_complete, data);
     return ret;
 }
 
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver stream_job_driver = {
         .job_type      = JOB_TYPE_STREAM,
         .free          = block_job_free,
         .run           = stream_run,
+        .exit          = stream_exit,
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
     },
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -XXX,XX +XXX,XX @@ typedef struct TestBlockJob {
     bool should_complete;
 } TestBlockJob;
 
-static void test_job_completed(Job *job, void *opaque)
-{
-    job_completed(job, 0);
-}
-
 static int coroutine_fn test_job_run(Job *job, Error **errp)
 {
     TestBlockJob *s = container_of(job, TestBlockJob, common.job);
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn test_job_run(Job *job, Error **errp)
         job_pause_point(&s->common.job);
     }
 
-    job_defer_to_main_loop(&s->common.job, test_job_completed, NULL);
     return 0;
 }
 
diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-blockjob-txn.c
+++ b/tests/test-blockjob-txn.c
@@ -XXX,XX +XXX,XX @@ typedef struct {
     int *result;
 } TestBlockJob;
 
-static void test_block_job_complete(Job *job, void *opaque)
+static void test_block_job_exit(Job *job)
 {
     BlockJob *bjob = container_of(job, BlockJob, job);
     BlockDriverState *bs = blk_bs(bjob->blk);
-    int rc = (intptr_t)opaque;
 
-    if (job_is_cancelled(job)) {
-        rc = -ECANCELED;
-    }
-
-    job_completed(job, rc);
     bdrv_unref(bs);
 }
 
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn test_block_job_run(Job *job, Error **errp)
         }
     }
 
-    job_defer_to_main_loop(job, test_block_job_complete,
-                           (void *)(intptr_t)s->rc);
     return s->rc;
 }
 
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_block_job_driver = {
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
         .run           = test_block_job_run,
+        .exit          = test_block_job_exit,
     },
 };
 
diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
index XXXXXXX..XXXXXXX 100644
--- a/tests/test-blockjob.c
+++ b/tests/test-blockjob.c
@@ -XXX,XX +XXX,XX @@ typedef struct CancelJob {
     bool completed;
 } CancelJob;
 
-static void cancel_job_completed(Job *job, void *opaque)
+static void cancel_job_exit(Job *job)
 {
-    CancelJob *s = opaque;
+    CancelJob *s = container_of(job, CancelJob, common.job);
     s->completed = true;
-    job_completed(job, 0);
 }
 
 static void cancel_job_complete(Job *job, Error **errp)
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn cancel_job_run(Job *job, Error **errp)
 
     while (!s->should_complete) {
         if (job_is_cancelled(&s->common.job)) {
-            goto defer;
+            return 0;
         }
 
         if (!job_is_ready(&s->common.job) && s->should_converge) {
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn cancel_job_run(Job *job, Error **errp)
         job_sleep_ns(&s->common.job, 100000);
     }
 
- defer:
-    job_defer_to_main_loop(&s->common.job, cancel_job_completed, s);
     return 0;
 }
 
@@ -XXX,XX +XXX,XX @@ static const BlockJobDriver test_cancel_driver = {
         .user_resume   = block_job_user_resume,
         .drain         = block_job_drain,
         .run           = cancel_job_run,
+        .exit          = cancel_job_exit,
         .complete      = cancel_job_complete,
     },
 };
-- 
2.17.1

From: John Snow <jsnow@redhat.com>

Rename opaque_job to job to be consistent with other job implementations.
Rename 'job', the BackupBlockJob object, to 's' to also be consistent.

Suggested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180830015734.19765-8-jsnow@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/backup.c | 62 +++++++++++++++++++++++++-------------------------
 1 file changed, 31 insertions(+), 31 deletions(-)

diff --git a/block/backup.c b/block/backup.c
index XXXXXXX..XXXXXXX 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -XXX,XX +XXX,XX @@ static void backup_incremental_init_copy_bitmap(BackupBlockJob *job)
     bdrv_dirty_iter_free(dbi);
 }
 
-static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
+static int coroutine_fn backup_run(Job *job, Error **errp)
 {
-    BackupBlockJob *job = container_of(opaque_job, BackupBlockJob, common.job);
-    BlockDriverState *bs = blk_bs(job->common.blk);
+    BackupBlockJob *s = container_of(job, BackupBlockJob, common.job);
+    BlockDriverState *bs = blk_bs(s->common.blk);
     int64_t offset, nb_clusters;
     int ret = 0;
 
-    QLIST_INIT(&job->inflight_reqs);
-    qemu_co_rwlock_init(&job->flush_rwlock);
+    QLIST_INIT(&s->inflight_reqs);
+    qemu_co_rwlock_init(&s->flush_rwlock);
 
-    nb_clusters = DIV_ROUND_UP(job->len, job->cluster_size);
-    job_progress_set_remaining(&job->common.job, job->len);
+    nb_clusters = DIV_ROUND_UP(s->len, s->cluster_size);
+    job_progress_set_remaining(job, s->len);
 
-    job->copy_bitmap = hbitmap_alloc(nb_clusters, 0);
-    if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
-        backup_incremental_init_copy_bitmap(job);
+    s->copy_bitmap = hbitmap_alloc(nb_clusters, 0);
+    if (s->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
+        backup_incremental_init_copy_bitmap(s);
     } else {
-        hbitmap_set(job->copy_bitmap, 0, nb_clusters);
+        hbitmap_set(s->copy_bitmap, 0, nb_clusters);
     }
 
 
-    job->before_write.notify = backup_before_write_notify;
-    bdrv_add_before_write_notifier(bs, &job->before_write);
+    s->before_write.notify = backup_before_write_notify;
+    bdrv_add_before_write_notifier(bs, &s->before_write);
 
-    if (job->sync_mode == MIRROR_SYNC_MODE_NONE) {
+    if (s->sync_mode == MIRROR_SYNC_MODE_NONE) {
         /* All bits are set in copy_bitmap to allow any cluster to be copied.
          * This does not actually require them to be copied. */
-        while (!job_is_cancelled(&job->common.job)) {
+        while (!job_is_cancelled(job)) {
             /* Yield until the job is cancelled.  We just let our before_write
              * notify callback service CoW requests. */
-            job_yield(&job->common.job);
+            job_yield(job);
         }
-    } else if (job->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
-        ret = backup_run_incremental(job);
+    } else if (s->sync_mode == MIRROR_SYNC_MODE_INCREMENTAL) {
+        ret = backup_run_incremental(s);
     } else {
         /* Both FULL and TOP SYNC_MODE's require copying.. */
-        for (offset = 0; offset < job->len;
-             offset += job->cluster_size) {
+        for (offset = 0; offset < s->len;
+             offset += s->cluster_size) {
             bool error_is_read;
             int alloced = 0;
 
-            if (yield_and_check(job)) {
+            if (yield_and_check(s)) {
                 break;
             }
 
-            if (job->sync_mode == MIRROR_SYNC_MODE_TOP) {
+            if (s->sync_mode == MIRROR_SYNC_MODE_TOP) {
                 int i;
                 int64_t n;
 
                 /* Check to see if these blocks are already in the
                  * backing file. */
 
-                for (i = 0; i < job->cluster_size;) {
+                for (i = 0; i < s->cluster_size;) {
                     /* bdrv_is_allocated() only returns true/false based
                      * on the first set of sectors it comes across that
                      * are are all in the same state.
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
                      * needed but at some point that is always the case. */
                     alloced =
                         bdrv_is_allocated(bs, offset + i,
-                                          job->cluster_size - i, &n);
+                                          s->cluster_size - i, &n);
                     i += n;
 
                     if (alloced || n == 0) {
@@ -XXX,XX +XXX,XX @@ static int coroutine_fn backup_run(Job *opaque_job, Error **errp)
             if (alloced < 0) {
                 ret = alloced;
             } else {
-                ret = backup_do_cow(job, offset, job->cluster_size,
+                ret = backup_do_cow(s, offset, s->cluster_size,
                                     &error_is_read, false);
             }
             if (ret < 0) {
                 /* Depending on error action, fail now or retry cluster */
                 BlockErrorAction action =
-                    backup_error_action(job, error_is_read, -ret);
+                    backup_error_action(s, error_is_read, -ret);
                 if (action == BLOCK_ERROR_ACTION_REPORT) {
                     break;
                 } else {
-                    offset -= job->cluster_size;
+                    offset -= s->cluster_size;
                     continue;
                 }
             }
         }
     }
 
-    notifier_with_return_remove(&job->before_write);
+    notifier_with_return_remove(&s->before_write);
 
     /* wait until pending backup_do_cow() calls have completed */
-    qemu_co_rwlock_wrlock(&job->flush_rwlock);
-    qemu_co_rwlock_unlock(&job->flush_rwlock);
-    hbitmap_free(job->copy_bitmap);
+    qemu_co_rwlock_wrlock(&s->flush_rwlock);
+    qemu_co_rwlock_unlock(&s->flush_rwlock);
+    hbitmap_free(s->copy_bitmap);
 
     return ret;
 }
-- 
2.17.1

From: John Snow <jsnow@redhat.com>

Jobs are now expected to return their retcode on the stack, from the
.run callback, so we can remove that argument.

job_cancel does not need to set -ECANCELED because job_completed will
update the return code itself if the job was canceled.

While we're here, make job_completed static to job.c and remove it from
job.h; move the documentation of return code to the .run() callback and
to the job->ret property, accordingly.

Signed-off-by: John Snow <jsnow@redhat.com>
Message-id: 20180830015734.19765-9-jsnow@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/qemu/job.h | 28 +++++++++++++++-------------
 job.c              | 11 ++++++-----
 trace-events       |  2 +-
 3 files changed, 22 insertions(+), 19 deletions(-)

From: John Snow <jsnow@redhat.com>

Now that the job infrastructure is handling the job_completed call for
all implemented jobs, we can remove the interface that allowed jobs to
schedule their own completion.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-id: 20180830015734.19765-10-jsnow@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 include/qemu/job.h | 17 -----------------
 job.c              | 40 ++--------------------------------------
 2 files changed, 2 insertions(+), 55 deletions(-)

diff --git a/include/qemu/job.h b/include/qemu/job.h
index XXXXXXX..XXXXXXX 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -XXX,XX +XXX,XX @@ void job_finalize(Job *job, Error **errp);
  */
 void job_dismiss(Job **job, Error **errp);
 
-typedef void JobDeferToMainLoopFn(Job *job, void *opaque);
-
-/**
- * @job: The job
- * @fn: The function to run in the main loop
- * @opaque: The opaque value that is passed to @fn
- *
- * This function must be called by the main job coroutine just before it
- * returns.  @fn is executed in the main loop with the job AioContext acquired.
- *
- * Block jobs must call bdrv_unref(), bdrv_close(), and anything that uses
- * bdrv_drain_all() in the main loop.
- *
- * The @job AioContext is held while @fn executes.
- */
-void job_defer_to_main_loop(Job *job, JobDeferToMainLoopFn *fn, void *opaque);
-
 /**
  * Synchronously finishes the given @job. If @finish is given, it is called to
  * trigger completion or cancellation of the job.
diff --git a/job.c b/job.c
index XXXXXXX..XXXXXXX 100644
--- a/job.c
+++ b/job.c
@@ -XXX,XX +XXX,XX @@ static void coroutine_fn job_co_entry(void *opaque)
     assert(job && job->driver && job->driver->run);
     job_pause_point(job);
     job->ret = job->driver->run(job, &job->err);
-    if (!job->deferred_to_main_loop) {
-        job->deferred_to_main_loop = true;
-        aio_bh_schedule_oneshot(qemu_get_aio_context(),
-                                job_exit,
-                                job);
-    }
+    job->deferred_to_main_loop = true;
+    aio_bh_schedule_oneshot(qemu_get_aio_context(), job_exit, job);
 }
 
 
@@ -XXX,XX +XXX,XX @@ void job_complete(Job *job, Error **errp)
     job->driver->complete(job, errp);
 }
 
-
-typedef struct {
-    Job *job;
-    JobDeferToMainLoopFn *fn;
-    void *opaque;
-} JobDeferToMainLoopData;
-
-static void job_defer_to_main_loop_bh(void *opaque)
-{
-    JobDeferToMainLoopData *data = opaque;
-    Job *job = data->job;
-    AioContext *aio_context = job->aio_context;
-
-    aio_context_acquire(aio_context);
-    data->fn(data->job, data->opaque);
-    aio_context_release(aio_context);
-
-    g_free(data);
-}
-
-void job_defer_to_main_loop(Job *job, JobDeferToMainLoopFn *fn, void *opaque)
-{
-    JobDeferToMainLoopData *data = g_malloc(sizeof(*data));
-    data->job = job;
-    data->fn = fn;
-    data->opaque = opaque;
-    job->deferred_to_main_loop = true;
-
-    aio_bh_schedule_oneshot(qemu_get_aio_context(),
-                            job_defer_to_main_loop_bh, data);
-}
-
 int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
 {
     Error *local_err = NULL;
-- 
2.17.1