job: drop job_drain

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>
Tested-by: John Snow <jsnow@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

4 files changed, 4 insertions, 45 deletions

diff --git a/block/backup.c b/block/backup.c
index 03637aeb11..763f0d7ff6 100644
--- a/block/backup.c
+++ b/block/backup.c
@@ -425,21 +425,6 @@ void backup_do_checkpoint(BlockJob *job, Error **errp)
     bdrv_set_dirty_bitmap(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)
 {
@@ -588,13 +573,11 @@ 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 408ae15389..bc8454463d 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 853e2c7510..fe984efb90 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -646,14 +646,11 @@ 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;
 
@@ -1149,28 +1146,12 @@ 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,
@@ -1178,7 +1159,6 @@ static const BlockJobDriver mirror_job_driver = {
         .complete               = mirror_complete,
     },
     .drained_poll           = mirror_drained_poll,
-    .drain                  = mirror_drain,
 };
 
 static const BlockJobDriver commit_active_job_driver = {
@@ -1187,7 +1167,6 @@ 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,
@@ -1195,7 +1174,6 @@ 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 0d3a6ac7c3..5562ccbf57 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -212,7 +212,6 @@ static const BlockJobDriver stream_job_driver = {
         .abort         = stream_abort,
         .clean         = stream_clean,
         .user_resume   = block_job_user_resume,
-        .drain         = block_job_drain,
     },
 };