[Devel] [PATCH rh7 2/2] nbd: quiesce request queues to make sure no submissions are inflight

[Andrey Ryabinin]

From: Sagi Grimberg <sagi at grimberg.me>

Unlike blk_mq_stop_hw_queues, blk_mq_quiesce_queue respects the
submission path rcu grace. quiesce the queue before iterating
on live tags.

Reviewed-by: Ming Lei <ming.lei at redhat.com>
Acked-by: Josef Bacik <jbacik at fb.com>
Signed-off-by: Sagi Grimberg <sagi at grimberg.me>

https://jira.sw.ru/browse/PSBM-99114
(cherry picked from commit b52c2e92546ee794a5bbab4d8ea435c1de85a8cb)
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
---
 drivers/block/nbd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 8e43eac169f4..4a17d320d7fa 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -642,9 +642,9 @@ static void nbd_clear_req(struct request *req, void *data, bool reserved)
 
 static void nbd_clear_que(struct nbd_device *nbd)
 {
-	blk_mq_stop_hw_queues(nbd->disk->queue);
+	blk_mq_quiesce_queue(nbd->disk->queue);
 	blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
-	blk_mq_start_hw_queues(nbd->disk->queue);
+	blk_mq_unquiesce_queue(nbd->disk->queue);
 	dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
 }
 
-- 
2.23.0