From: Alejandro Zeise <alejandro.zeise@seagate.com>
In order to support a new update function, a flag needs to be passed
to the kernel via the socket send call (MSG_MORE) to notify it that
more data is to be expected to calculate the hash correctly.
Add a new iov helper for this purpose.
Signed-off-by: Alejandro Zeise <alejandro.zeise@seagate.com>
[ clg: - Split iov changes from original patch
- Checkpatch fixes ]
Signed-off-by: Cédric Le Goater <clg@redhat.com>
---
include/qemu/iov.h | 27 +++++++++++++++++++++++++++
util/iov.c | 25 ++++++++++++++++++-------
2 files changed, 45 insertions(+), 7 deletions(-)
diff --git a/include/qemu/iov.h b/include/qemu/iov.h
index 63a1c01965d1..44f9db5cee97 100644
--- a/include/qemu/iov.h
+++ b/include/qemu/iov.h
@@ -1,6 +1,7 @@
/*
* Helpers for using (partial) iovecs.
*
+ * Copyright (c) 2024 Seagate Technology LLC and/or its Affiliates
* Copyright (C) 2010 Red Hat, Inc.
*
* Author(s):
@@ -75,6 +76,32 @@ iov_to_buf(const struct iovec *iov, const unsigned int iov_cnt,
size_t iov_memset(const struct iovec *iov, const unsigned int iov_cnt,
size_t offset, int fillc, size_t bytes);
+/*
+ * Send/recv data from/to iovec buffers directly, with the provided
+ * socket flags.
+ *
+ * `offset' bytes in the beginning of iovec buffer are skipped and
+ * next `bytes' bytes are used, which must be within data of iovec.
+ *
+ * r = iov_send_recv_with_flags(sockfd, sockflags, iov, iovcnt,
+ * offset, bytes, true);
+ *
+ * is logically equivalent to
+ *
+ * char *buf = malloc(bytes);
+ * iov_to_buf(iov, iovcnt, offset, buf, bytes);
+ * r = send(sockfd, buf, bytes, sockflags);
+ * free(buf);
+ *
+ * For iov_send_recv_with_flags() _whole_ area being sent or received
+ * should be within the iovec, not only beginning of it.
+ */
+ssize_t iov_send_recv_with_flags(int sockfd, int sockflags,
+ const struct iovec *iov,
+ unsigned iov_cnt, size_t offset,
+ size_t bytes,
+ bool do_send);
+
/*
* Send/recv data from/to iovec buffers directly
*
diff --git a/util/iov.c b/util/iov.c
index 7e73948f5e3d..7777116123d0 100644
--- a/util/iov.c
+++ b/util/iov.c
@@ -3,6 +3,7 @@
*
* Copyright IBM, Corp. 2007, 2008
* Copyright (C) 2010 Red Hat, Inc.
+ * Copyright (c) 2024 Seagate Technology LLC and/or its Affiliates
*
* Author(s):
* Anthony Liguori <aliguori@us.ibm.com>
@@ -92,7 +93,8 @@ size_t iov_size(const struct iovec *iov, const unsigned int iov_cnt)
/* helper function for iov_send_recv() */
static ssize_t
-do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send)
+do_send_recv(int sockfd, int flags, struct iovec *iov, unsigned iov_cnt,
+ bool do_send)
{
#ifdef CONFIG_POSIX
ssize_t ret;
@@ -102,8 +104,8 @@ do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send)
msg.msg_iovlen = iov_cnt;
do {
ret = do_send
- ? sendmsg(sockfd, &msg, 0)
- : recvmsg(sockfd, &msg, 0);
+ ? sendmsg(sockfd, &msg, flags)
+ : recvmsg(sockfd, &msg, flags);
} while (ret < 0 && errno == EINTR);
return ret;
#else
@@ -114,8 +116,8 @@ do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send)
ssize_t off = 0;
while (i < iov_cnt) {
ssize_t r = do_send
- ? send(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, 0)
- : recv(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, 0);
+ ? send(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, flags)
+ : recv(sockfd, iov[i].iov_base + off, iov[i].iov_len - off, flags);
if (r > 0) {
ret += r;
off += r;
@@ -144,6 +146,15 @@ do_send_recv(int sockfd, struct iovec *iov, unsigned iov_cnt, bool do_send)
ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt,
size_t offset, size_t bytes,
bool do_send)
+{
+ return iov_send_recv_with_flags(sockfd, 0, _iov, iov_cnt, offset, bytes,
+ do_send);
+}
+
+ssize_t iov_send_recv_with_flags(int sockfd, int sockflags,
+ const struct iovec *_iov,
+ unsigned iov_cnt, size_t offset,
+ size_t bytes, bool do_send)
{
ssize_t total = 0;
ssize_t ret;
@@ -192,11 +203,11 @@ ssize_t iov_send_recv(int sockfd, const struct iovec *_iov, unsigned iov_cnt,
assert(iov[niov].iov_len > tail);
orig_len = iov[niov].iov_len;
iov[niov++].iov_len = tail;
- ret = do_send_recv(sockfd, iov, niov, do_send);
+ ret = do_send_recv(sockfd, sockflags, iov, niov, do_send);
/* Undo the changes above before checking for errors */
iov[niov-1].iov_len = orig_len;
} else {
- ret = do_send_recv(sockfd, iov, niov, do_send);
+ ret = do_send_recv(sockfd, sockflags, iov, niov, do_send);
}
if (offset) {
iov[0].iov_base -= offset;
--
2.46.2