From: Ming Lei ming.lei@redhat.com
[ Upstream commit e766668c6cd49d741cfb49eaeb38998ba34d27bc ]
dm_stop_queue() only uses blk_mq_quiesce_queue() so it doesn't formally stop the blk-mq queue; therefore there is no point making the blk_mq_queue_stopped() check -- it will never be stopped.
In addition, even though dm_stop_queue() actually tries to quiesce hw queues via blk_mq_quiesce_queue(), checking with blk_queue_quiesced() to avoid unnecessary queue quiesce isn't reliable because: the QUEUE_FLAG_QUIESCED flag is set before synchronize_rcu() and dm_stop_queue() may be called when synchronize_rcu() from another blk_mq_quiesce_queue() is in-progress.
Fixes: 7b17c2f7292ba ("dm: Fix a race condition related to stopping and starting queues") Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/dm-rq.c | 3 --- 1 file changed, 3 deletions(-)
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c index eadfcfd106fff..cac8ec16e6031 100644 --- a/drivers/md/dm-rq.c +++ b/drivers/md/dm-rq.c @@ -95,9 +95,6 @@ static void dm_old_stop_queue(struct request_queue *q)
static void dm_mq_stop_queue(struct request_queue *q) { - if (blk_mq_queue_stopped(q)) - return; - blk_mq_quiesce_queue(q); }