[Qemu-devel] [PATCH v2] job: drop job_drain

Vladimir Sementsov-Ogievskiy posted 1 patch 4 years, 7 months ago
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git fetch https://github.com/patchew-project/qemu tags/patchew/20190823143224.338486-1-vsementsov@virtuozzo.com
Maintainers: John Snow <jsnow@redhat.com>, Kevin Wolf <kwolf@redhat.com>, Max Reitz <mreitz@redhat.com>
There is a newer version of this series
include/block/blockjob_int.h | 19 -------------------
include/qemu/job.h           | 13 -------------
block/backup.c               | 19 +------------------
block/commit.c               |  1 -
block/mirror.c               | 28 +++-------------------------
block/stream.c               |  1 -
blockjob.c                   | 13 -------------
job.c                        | 12 +-----------
tests/test-bdrv-drain.c      |  2 --
tests/test-block-iothread.c  |  1 -
tests/test-blockjob-txn.c    |  1 -
tests/test-blockjob.c        |  2 --
12 files changed, 5 insertions(+), 107 deletions(-)
[Qemu-devel] [PATCH v2] job: drop job_drain
Posted by Vladimir Sementsov-Ogievskiy 4 years, 7 months ago
In job_finish_sync job_enter should be enough for a job to make some
progress and draining is a wrong tool for it. So use job_enter directly
here and drop job_drain with all related staff not used more.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---

v2: drop drain from tests/test-*, which I missed in v1

 include/block/blockjob_int.h | 19 -------------------
 include/qemu/job.h           | 13 -------------
 block/backup.c               | 19 +------------------
 block/commit.c               |  1 -
 block/mirror.c               | 28 +++-------------------------
 block/stream.c               |  1 -
 blockjob.c                   | 13 -------------
 job.c                        | 12 +-----------
 tests/test-bdrv-drain.c      |  2 --
 tests/test-block-iothread.c  |  1 -
 tests/test-blockjob-txn.c    |  1 -
 tests/test-blockjob.c        |  2 --
 12 files changed, 5 insertions(+), 107 deletions(-)

diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
index e4a318dd15..e2824a36a8 100644
--- a/include/block/blockjob_int.h
+++ b/include/block/blockjob_int.h
@@ -52,17 +52,6 @@ struct BlockJobDriver {
      * besides job->blk to the new AioContext.
      */
     void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
-
-    /*
-     * If the callback is not NULL, it will be invoked when the job has to be
-     * synchronously cancelled or completed; it should drain BlockDriverStates
-     * as required to ensure progress.
-     *
-     * Block jobs must use the default implementation for job_driver.drain,
-     * which will in turn call this callback after doing generic block job
-     * stuff.
-     */
-    void (*drain)(BlockJob *job);
 };
 
 /**
@@ -107,14 +96,6 @@ void block_job_free(Job *job);
  */
 void block_job_user_resume(Job *job);
 
-/**
- * block_job_drain:
- * Callback to be used for JobDriver.drain in all block jobs. Drains the main
- * block node associated with the block jobs and calls BlockJobDriver.drain for
- * job-specific actions.
- */
-void block_job_drain(Job *job);
-
 /**
  * block_job_ratelimit_get_delay:
  *
diff --git a/include/qemu/job.h b/include/qemu/job.h
index 9e7cd1e4a0..09739b8dd9 100644
--- a/include/qemu/job.h
+++ b/include/qemu/job.h
@@ -220,13 +220,6 @@ struct JobDriver {
      */
     void (*complete)(Job *job, Error **errp);
 
-    /*
-     * If the callback is not NULL, it will be invoked when the job has to be
-     * synchronously cancelled or completed; it should drain any activities
-     * as required to ensure progress.
-     */
-    void (*drain)(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
@@ -470,12 +463,6 @@ bool job_user_paused(Job *job);
  */
 void job_user_resume(Job *job, Error **errp);
 
-/*
- * Drain any activities as required to ensure progress. This can be called in a
- * loop to synchronously complete a job.
- */
-void job_drain(Job *job);
-
 /**
  * Get the next element from the list of block jobs after @job, or the
  * first one if @job is %NULL.
diff --git a/block/backup.c b/block/backup.c
index 715e1d3be8..d1ecdfa9aa 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -320,21 +320,6 @@ void backup_do_checkpoint(BlockJob *job, Error **errp)
     hbitmap_set(backup_job->copy_bitmap, 0, backup_job->len);
 }
 
-static void backup_drain(BlockJob *job)
-{
-    BackupBlockJob *s = container_of(job, BackupBlockJob, common);
-
-    /* Need to keep a reference in case blk_drain triggers execution
-     * of backup_complete...
-     */
-    if (s->target) {
-        BlockBackend *target = s->target;
-        blk_ref(target);
-        blk_drain(target);
-        blk_unref(target);
-    }
-}
-
 static BlockErrorAction backup_error_action(BackupBlockJob *job,
                                             bool read, int error)
 {
@@ -488,13 +473,11 @@ static const BlockJobDriver backup_job_driver = {
         .job_type               = JOB_TYPE_BACKUP,
         .free                   = block_job_free,
         .user_resume            = block_job_user_resume,
-        .drain                  = block_job_drain,
         .run                    = backup_run,
         .commit                 = backup_commit,
         .abort                  = backup_abort,
         .clean                  = backup_clean,
-    },
-    .drain                  = backup_drain,
+    }
 };
 
 static int64_t backup_calculate_cluster_size(BlockDriverState *target,
diff --git a/block/commit.c b/block/commit.c
index 2c5a6d4ebc..697a779d8e 100644
--- a/block/commit.c
+++ b/block/commit.c
@@ -216,7 +216,6 @@ static const BlockJobDriver commit_job_driver = {
         .job_type      = JOB_TYPE_COMMIT,
         .free          = block_job_free,
         .user_resume   = block_job_user_resume,
-        .drain         = block_job_drain,
         .run           = commit_run,
         .prepare       = commit_prepare,
         .abort         = commit_abort,
diff --git a/block/mirror.c b/block/mirror.c
index 8cb75fb409..b91abe0288 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -644,14 +644,11 @@ static int mirror_exit_common(Job *job)
     bdrv_ref(mirror_top_bs);
     bdrv_ref(target_bs);
 
-    /* Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
+    /*
+     * Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
      * inserting target_bs at s->to_replace, where we might not be able to get
      * these permissions.
-     *
-     * Note that blk_unref() alone doesn't necessarily drop permissions because
-     * we might be running nested inside mirror_drain(), which takes an extra
-     * reference, so use an explicit blk_set_perm() first. */
-    blk_set_perm(s->target, 0, BLK_PERM_ALL, &error_abort);
+     */
     blk_unref(s->target);
     s->target = NULL;
 
@@ -1143,28 +1140,12 @@ static bool mirror_drained_poll(BlockJob *job)
     return !!s->in_flight;
 }
 
-static void mirror_drain(BlockJob *job)
-{
-    MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
-
-    /* Need to keep a reference in case blk_drain triggers execution
-     * of mirror_complete...
-     */
-    if (s->target) {
-        BlockBackend *target = s->target;
-        blk_ref(target);
-        blk_drain(target);
-        blk_unref(target);
-    }
-}
-
 static const BlockJobDriver mirror_job_driver = {
     .job_driver = {
         .instance_size          = sizeof(MirrorBlockJob),
         .job_type               = JOB_TYPE_MIRROR,
         .free                   = block_job_free,
         .user_resume            = block_job_user_resume,
-        .drain                  = block_job_drain,
         .run                    = mirror_run,
         .prepare                = mirror_prepare,
         .abort                  = mirror_abort,
@@ -1172,7 +1153,6 @@ static const BlockJobDriver mirror_job_driver = {
         .complete               = mirror_complete,
     },
     .drained_poll           = mirror_drained_poll,
-    .drain                  = mirror_drain,
 };
 
 static const BlockJobDriver commit_active_job_driver = {
@@ -1181,7 +1161,6 @@ static const BlockJobDriver commit_active_job_driver = {
         .job_type               = JOB_TYPE_COMMIT,
         .free                   = block_job_free,
         .user_resume            = block_job_user_resume,
-        .drain                  = block_job_drain,
         .run                    = mirror_run,
         .prepare                = mirror_prepare,
         .abort                  = mirror_abort,
@@ -1189,7 +1168,6 @@ static const BlockJobDriver commit_active_job_driver = {
         .complete               = mirror_complete,
     },
     .drained_poll           = mirror_drained_poll,
-    .drain                  = mirror_drain,
 };
 
 static void coroutine_fn
diff --git a/block/stream.c b/block/stream.c
index 6ac1e7bec4..07f9908e1a 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -218,7 +218,6 @@ static const BlockJobDriver stream_job_driver = {
         .abort         = stream_abort,
         .clean         = stream_clean,
         .user_resume   = block_job_user_resume,
-        .drain         = block_job_drain,
     },
 };
 
diff --git a/blockjob.c b/blockjob.c
index 20b7f557da..4b8d0869c6 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -89,18 +89,6 @@ void block_job_free(Job *job)
     error_free(bjob->blocker);
 }
 
-void block_job_drain(Job *job)
-{
-    BlockJob *bjob = container_of(job, BlockJob, job);
-    const JobDriver *drv = job->driver;
-    BlockJobDriver *bjdrv = container_of(drv, BlockJobDriver, job_driver);
-
-    blk_drain(bjob->blk);
-    if (bjdrv->drain) {
-        bjdrv->drain(bjob);
-    }
-}
-
 static char *child_job_get_parent_desc(BdrvChild *c)
 {
     BlockJob *job = c->opaque;
@@ -421,7 +409,6 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
     assert(is_block_job(&job->job));
     assert(job->job.driver->free == &block_job_free);
     assert(job->job.driver->user_resume == &block_job_user_resume);
-    assert(job->job.driver->drain == &block_job_drain);
 
     job->blk = blk;
 
diff --git a/job.c b/job.c
index 28dd48f8a5..04409b40aa 100644
--- a/job.c
+++ b/job.c
@@ -523,16 +523,6 @@ void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
     job_pause_point(job);
 }
 
-void job_drain(Job *job)
-{
-    /* If job is !busy this kicks it into the next pause point. */
-    job_enter(job);
-
-    if (job->driver->drain) {
-        job->driver->drain(job);
-    }
-}
-
 /* Assumes the block_job_mutex is held */
 static bool job_timer_not_pending(Job *job)
 {
@@ -991,7 +981,7 @@ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
     }
 
     AIO_WAIT_WHILE(job->aio_context,
-                   (job_drain(job), !job_is_completed(job)));
+                   (job_enter(job), !job_is_completed(job)));
 
     ret = (job_is_cancelled(job) && job->ret == 0) ? -ECANCELED : job->ret;
     job_unref(job);
diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
index 03fa1142a1..efbce9f8b4 100644
--- a/tests/test-bdrv-drain.c
+++ b/tests/test-bdrv-drain.c
@@ -837,7 +837,6 @@ BlockJobDriver test_job_driver = {
         .instance_size  = sizeof(TestBlockJob),
         .free           = block_job_free,
         .user_resume    = block_job_user_resume,
-        .drain          = block_job_drain,
         .run            = test_job_run,
         .complete       = test_job_complete,
         .prepare        = test_job_prepare,
@@ -1563,7 +1562,6 @@ static const BlockJobDriver test_drop_backing_job_driver = {
         .instance_size  = sizeof(TestDropBackingBlockJob),
         .free           = block_job_free,
         .user_resume    = block_job_user_resume,
-        .drain          = block_job_drain,
         .run            = test_drop_backing_job_run,
         .commit         = test_drop_backing_job_commit,
     }
diff --git a/tests/test-block-iothread.c b/tests/test-block-iothread.c
index 1949d5e61a..cbd1bbdde4 100644
--- a/tests/test-block-iothread.c
+++ b/tests/test-block-iothread.c
@@ -400,7 +400,6 @@ BlockJobDriver test_job_driver = {
         .instance_size  = sizeof(TestBlockJob),
         .free           = block_job_free,
         .user_resume    = block_job_user_resume,
-        .drain          = block_job_drain,
         .run            = test_job_run,
         .complete       = test_job_complete,
         .prepare        = test_job_prepare,
diff --git a/tests/test-blockjob-txn.c b/tests/test-blockjob-txn.c
index 86606f92b3..1023d68812 100644
--- a/tests/test-blockjob-txn.c
+++ b/tests/test-blockjob-txn.c
@@ -71,7 +71,6 @@ static const BlockJobDriver test_block_job_driver = {
         .instance_size = sizeof(TestBlockJob),
         .free          = block_job_free,
         .user_resume   = block_job_user_resume,
-        .drain         = block_job_drain,
         .run           = test_block_job_run,
         .clean         = test_block_job_clean,
     },
diff --git a/tests/test-blockjob.c b/tests/test-blockjob.c
index b33f899873..01841b16de 100644
--- a/tests/test-blockjob.c
+++ b/tests/test-blockjob.c
@@ -21,7 +21,6 @@ static const BlockJobDriver test_block_job_driver = {
         .instance_size = sizeof(BlockJob),
         .free          = block_job_free,
         .user_resume   = block_job_user_resume,
-        .drain         = block_job_drain,
     },
 };
 
@@ -193,7 +192,6 @@ static const BlockJobDriver test_cancel_driver = {
         .instance_size = sizeof(CancelJob),
         .free          = block_job_free,
         .user_resume   = block_job_user_resume,
-        .drain         = block_job_drain,
         .run           = cancel_job_run,
         .complete      = cancel_job_complete,
     },
-- 
2.18.0


Re: [Qemu-devel] [PATCH v2] job: drop job_drain
Posted by John Snow 4 years, 7 months ago

On 8/23/19 10:32 AM, Vladimir Sementsov-Ogievskiy wrote:
> In job_finish_sync job_enter should be enough for a job to make some
> progress and draining is a wrong tool for it. So use job_enter directly
> here and drop job_drain with all related staff not used more.
> 
> Suggested-by: Kevin Wolf <kwolf@redhat.com>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
> 
> v2: drop drain from tests/test-*, which I missed in v1

This patch has rotted a little, but not badly enough that --3way can't
handle it.

> 
>  include/block/blockjob_int.h | 19 -------------------
>  include/qemu/job.h           | 13 -------------
>  block/backup.c               | 19 +------------------
>  block/commit.c               |  1 -
>  block/mirror.c               | 28 +++-------------------------
>  block/stream.c               |  1 -
>  blockjob.c                   | 13 -------------
>  job.c                        | 12 +-----------
>  tests/test-bdrv-drain.c      |  2 --
>  tests/test-block-iothread.c  |  1 -
>  tests/test-blockjob-txn.c    |  1 -
>  tests/test-blockjob.c        |  2 --
>  12 files changed, 5 insertions(+), 107 deletions(-)
> 
> diff --git a/include/block/blockjob_int.h b/include/block/blockjob_int.h
> index e4a318dd15..e2824a36a8 100644
> --- a/include/block/blockjob_int.h
> +++ b/include/block/blockjob_int.h
> @@ -52,17 +52,6 @@ struct BlockJobDriver {
>       * besides job->blk to the new AioContext.
>       */
>      void (*attached_aio_context)(BlockJob *job, AioContext *new_context);
> -
> -    /*
> -     * If the callback is not NULL, it will be invoked when the job has to be
> -     * synchronously cancelled or completed; it should drain BlockDriverStates
> -     * as required to ensure progress.
> -     *
> -     * Block jobs must use the default implementation for job_driver.drain,
> -     * which will in turn call this callback after doing generic block job
> -     * stuff.
> -     */
> -    void (*drain)(BlockJob *job);
>  };
>  
>  /**
> @@ -107,14 +96,6 @@ void block_job_free(Job *job);
>   */
>  void block_job_user_resume(Job *job);
>  
> -/**
> - * block_job_drain:
> - * Callback to be used for JobDriver.drain in all block jobs. Drains the main
> - * block node associated with the block jobs and calls BlockJobDriver.drain for
> - * job-specific actions.
> - */
> -void block_job_drain(Job *job);
> -
>  /**
>   * block_job_ratelimit_get_delay:
>   *
> diff --git a/include/qemu/job.h b/include/qemu/job.h
> index 9e7cd1e4a0..09739b8dd9 100644
> --- a/include/qemu/job.h
> +++ b/include/qemu/job.h
> @@ -220,13 +220,6 @@ struct JobDriver {
>       */
>      void (*complete)(Job *job, Error **errp);
>  
> -    /*
> -     * If the callback is not NULL, it will be invoked when the job has to be
> -     * synchronously cancelled or completed; it should drain any activities
> -     * as required to ensure progress.
> -     */
> -    void (*drain)(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
> @@ -470,12 +463,6 @@ bool job_user_paused(Job *job);
>   */
>  void job_user_resume(Job *job, Error **errp);
>  
> -/*
> - * Drain any activities as required to ensure progress. This can be called in a
> - * loop to synchronously complete a job.
> - */
> -void job_drain(Job *job);
> -
>  /**
>   * Get the next element from the list of block jobs after @job, or the
>   * first one if @job is %NULL.
> diff --git a/block/backup.c b/block/backup.c
> index 715e1d3be8..d1ecdfa9aa 100644
> --- a/block/backup.c
> +++ b/block/backup.c
> @@ -320,21 +320,6 @@ void backup_do_checkpoint(BlockJob *job, Error **errp)
>      hbitmap_set(backup_job->copy_bitmap, 0, backup_job->len);
>  }
>  
> -static void backup_drain(BlockJob *job)
> -{
> -    BackupBlockJob *s = container_of(job, BackupBlockJob, common);
> -
> -    /* Need to keep a reference in case blk_drain triggers execution
> -     * of backup_complete...
> -     */
> -    if (s->target) {
> -        BlockBackend *target = s->target;
> -        blk_ref(target);
> -        blk_drain(target);
> -        blk_unref(target);
> -    }
> -}
> -
>  static BlockErrorAction backup_error_action(BackupBlockJob *job,
>                                              bool read, int error)
>  {
> @@ -488,13 +473,11 @@ static const BlockJobDriver backup_job_driver = {
>          .job_type               = JOB_TYPE_BACKUP,
>          .free                   = block_job_free,
>          .user_resume            = block_job_user_resume,
> -        .drain                  = block_job_drain,
>          .run                    = backup_run,
>          .commit                 = backup_commit,
>          .abort                  = backup_abort,
>          .clean                  = backup_clean,
> -    },
> -    .drain                  = backup_drain,
> +    }
>  };
>  
>  static int64_t backup_calculate_cluster_size(BlockDriverState *target,
> diff --git a/block/commit.c b/block/commit.c
> index 2c5a6d4ebc..697a779d8e 100644
> --- a/block/commit.c
> +++ b/block/commit.c
> @@ -216,7 +216,6 @@ static const BlockJobDriver commit_job_driver = {
>          .job_type      = JOB_TYPE_COMMIT,
>          .free          = block_job_free,
>          .user_resume   = block_job_user_resume,
> -        .drain         = block_job_drain,
>          .run           = commit_run,
>          .prepare       = commit_prepare,
>          .abort         = commit_abort,
> diff --git a/block/mirror.c b/block/mirror.c
> index 8cb75fb409..b91abe0288 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -644,14 +644,11 @@ static int mirror_exit_common(Job *job)
>      bdrv_ref(mirror_top_bs);
>      bdrv_ref(target_bs);
>  
> -    /* Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
> +    /*
> +     * Remove target parent that still uses BLK_PERM_WRITE/RESIZE before
>       * inserting target_bs at s->to_replace, where we might not be able to get
>       * these permissions.
> -     *
> -     * Note that blk_unref() alone doesn't necessarily drop permissions because
> -     * we might be running nested inside mirror_drain(), which takes an extra
> -     * reference, so use an explicit blk_set_perm() first. */
> -    blk_set_perm(s->target, 0, BLK_PERM_ALL, &error_abort);
> +     */
>      blk_unref(s->target);
>      s->target = NULL;
>  
> @@ -1143,28 +1140,12 @@ static bool mirror_drained_poll(BlockJob *job)
>      return !!s->in_flight;
>  }
>  
> -static void mirror_drain(BlockJob *job)
> -{
> -    MirrorBlockJob *s = container_of(job, MirrorBlockJob, common);
> -
> -    /* Need to keep a reference in case blk_drain triggers execution
> -     * of mirror_complete...
> -     */
> -    if (s->target) {
> -        BlockBackend *target = s->target;
> -        blk_ref(target);
> -        blk_drain(target);
> -        blk_unref(target);
> -    }
> -}
> -
>  static const BlockJobDriver mirror_job_driver = {
>      .job_driver = {
>          .instance_size          = sizeof(MirrorBlockJob),
>          .job_type               = JOB_TYPE_MIRROR,
>          .free                   = block_job_free,
>          .user_resume            = block_job_user_resume,
> -        .drain                  = block_job_drain,
>          .run                    = mirror_run,
>          .prepare                = mirror_prepare,
>          .abort                  = mirror_abort,
> @@ -1172,7 +1153,6 @@ static const BlockJobDriver mirror_job_driver = {
>          .complete               = mirror_complete,
>      },
>      .drained_poll           = mirror_drained_poll,
> -    .drain                  = mirror_drain,
>  };
>  
>  static const BlockJobDriver commit_active_job_driver = {
> @@ -1181,7 +1161,6 @@ static const BlockJobDriver commit_active_job_driver = {
>          .job_type               = JOB_TYPE_COMMIT,
>          .free                   = block_job_free,
>          .user_resume            = block_job_user_resume,
> -        .drain                  = block_job_drain,
>          .run                    = mirror_run,
>          .prepare                = mirror_prepare,
>          .abort                  = mirror_abort,
> @@ -1189,7 +1168,6 @@ static const BlockJobDriver commit_active_job_driver = {
>          .complete               = mirror_complete,
>      },
>      .drained_poll           = mirror_drained_poll,
> -    .drain                  = mirror_drain,
>  };
>  
>  static void coroutine_fn
> diff --git a/block/stream.c b/block/stream.c
> index 6ac1e7bec4..07f9908e1a 100644
> --- a/block/stream.c
> +++ b/block/stream.c
> @@ -218,7 +218,6 @@ static const BlockJobDriver stream_job_driver = {
>          .abort         = stream_abort,
>          .clean         = stream_clean,
>          .user_resume   = block_job_user_resume,
> -        .drain         = block_job_drain,
>      },
>  };
>  
> diff --git a/blockjob.c b/blockjob.c
> index 20b7f557da..4b8d0869c6 100644
> --- a/blockjob.c
> +++ b/blockjob.c
> @@ -89,18 +89,6 @@ void block_job_free(Job *job)
>      error_free(bjob->blocker);
>  }
>  
> -void block_job_drain(Job *job)
> -{
> -    BlockJob *bjob = container_of(job, BlockJob, job);
> -    const JobDriver *drv = job->driver;
> -    BlockJobDriver *bjdrv = container_of(drv, BlockJobDriver, job_driver);
> -
> -    blk_drain(bjob->blk);
> -    if (bjdrv->drain) {
> -        bjdrv->drain(bjob);
> -    }
> -}
> -
>  static char *child_job_get_parent_desc(BdrvChild *c)
>  {
>      BlockJob *job = c->opaque;
> @@ -421,7 +409,6 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
>      assert(is_block_job(&job->job));
>      assert(job->job.driver->free == &block_job_free);
>      assert(job->job.driver->user_resume == &block_job_user_resume);
> -    assert(job->job.driver->drain == &block_job_drain);
>  
>      job->blk = blk;
>  
> diff --git a/job.c b/job.c
> index 28dd48f8a5..04409b40aa 100644
> --- a/job.c
> +++ b/job.c
> @@ -523,16 +523,6 @@ void coroutine_fn job_sleep_ns(Job *job, int64_t ns)
>      job_pause_point(job);
>  }
>  
> -void job_drain(Job *job)
> -{
> -    /* If job is !busy this kicks it into the next pause point. */
> -    job_enter(job);
> -
> -    if (job->driver->drain) {
> -        job->driver->drain(job);
> -    }
> -}
> -
>  /* Assumes the block_job_mutex is held */
>  static bool job_timer_not_pending(Job *job)
>  {
> @@ -991,7 +981,7 @@ int job_finish_sync(Job *job, void (*finish)(Job *, Error **errp), Error **errp)
>      }
>  
>      AIO_WAIT_WHILE(job->aio_context,
> -                   (job_drain(job), !job_is_completed(job)));
> +                   (job_enter(job), !job_is_completed(job)));
>  
>      ret = (job_is_cancelled(job) && job->ret == 0) ? -ECANCELED : job->ret;
>      job_unref(job);
> diff --git a/tests/test-bdrv-drain.c b/tests/test-bdrv-drain.c
> index 03fa1142a1..efbce9f8b4 100644
> --- a/tests/test-bdrv-drain.c
> +++ b/tests/test-bdrv-drain.c
> @@ -837,7 +837,6 @@ BlockJobDriver test_job_driver = {
>          .instance_size  = sizeof(TestBlockJob),
>          .free           = block_job_free,
>          .user_resume    = block_job_user_resume,
> -        .drain          = block_job_drain,
>          .run            = test_job_run,
>          .complete       = test_job_complete,
>          .prepare        = test_job_prepare,
> @@ -1563,7 +1562,6 @@ static const BlockJobDriver test_drop_backing_job_driver = {
>          .instance_size  = sizeof(TestDropBackingBlockJob),
>          .free           = block_job_free,
>          .user_resume    = block_job_user_resume,
> -        .drain          = block_job_drain,
>          .run            = test_drop_backing_job_run,
>          .commit         = test_drop_backing_job_commit,
>      }

I think this misses test_simple_job_driver; which must be newly
committed. If I fix it, everything seems like it works out OK.

So with that fixed, I would feel comfortable saying:

Tested-by: John Snow <jsnow@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>