[PATCH 10/14] blk-mq: skip non-mq queues in blk_mq_quiesce_queue

Christoph Hellwig
2022-11-01T15:01:58Z

For submit_bio based queues there is no (S)RCU critical section during
I/O submission and thus nothing to wait for in blk_mq_wait_quiesce_done,
so skip doing any synchronization. No non-mq driver should be calling
this, but for now we have core callers that unconditionally call into it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
---
block/blk-mq.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 623e8a506539c..b8f37cfd3ae22 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -280,7 +280,9 @@ EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done);
void blk_mq_quiesce_queue(struct request_queue *q)
{
blk_mq_quiesce_queue_nowait(q);
- blk_mq_wait_quiesce_done(q);
+ /* nothing to wait for non-mq queues */
+ if (queue_is_mq(q))
+ blk_mq_wait_quiesce_done(q);
}
EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);

--
2.30.2