On 2022/10/20 18:56, Christoph Hellwig wrote:
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.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
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 33292c01875d5..df967c8af9fee 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);
For the non-mq queues, maybe we should add a synchronize_rcu.
if (queue_is_mq(q))
blk_mq_wait_quiesce_done(q);
else
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
