block: remove unused BLOCK_OP_TYPE_DATAPLANE

BLOCK_OP_TYPE_DATAPLANE prevents BlockDriverState from being used by
virtio-blk/virtio-scsi with IOThread. Commit b112a65c52aa ("block:
declare blockjobs and dataplane friends!") eliminated the main reason
for this blocker in 2014.

Nowadays the block layer supports I/O from multiple AioContexts, so
there is even less reason to block IOThread users. Any legitimate
reasons related to interference would probably also apply to
non-IOThread users.

The only remaining users are bdrv_op_unblock(BLOCK_OP_TYPE_DATAPLANE)
calls after bdrv_op_block_all(). If we remove BLOCK_OP_TYPE_DATAPLANE
their behavior doesn't change.

Existing bdrv_op_block_all() callers that don't explicitly unblock
BLOCK_OP_TYPE_DATAPLANE seem to do so simply because no one bothered to
rather than because it is necessary to keep BLOCK_OP_TYPE_DATAPLANE
blocked.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-ID: <20250203182529.269066-1-stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 0 insertions, 2 deletions

diff --git a/blockjob.c b/blockjob.c
index e94a840d7f..32007f31a9 100644
--- a/blockjob.c
+++ b/blockjob.c
@@ -539,8 +539,6 @@ void *block_job_create(const char *job_id, const BlockJobDriver *driver,
         goto fail;
     }
 
-    bdrv_op_unblock(bs, BLOCK_OP_TYPE_DATAPLANE, job->blocker);
-
     if (!block_job_set_speed(job, speed, errp)) {
         goto fail;
     }