From: Sagi Grimberg <sagi@grimberg.me>
Date: Tue, 4 Jul 2017 09:57:09 +0300
Subject: [PATCH] nbd: quiesce request queues to make sure no submissions are
Git-commit: b52c2e92546ee794a5bbab4d8ea435c1de85a8cb
Patch-mainline: v4.13-rc1
References: bsc#1104967,FATE#325924
 inflight

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@redhat.com>
Acked-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Hannes Reinecke <hare@suse.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 977ec960dd2f..dea7d85134ee 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -661,9 +661,9 @@ 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");
 }
 
-- 
2.16.4