From: Sagi Grimberg <sagi@grimberg.me>
Date: Tue, 4 Jul 2017 06:57:09 +0000 (+0300)
Subject: nbd: quiesce request queues to make sure no submissions are inflight
X-Git-Tag: v4.14-rc1~495^2~1^2~9
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b52c2e92546ee794a5bbab4d8ea435c1de85a8cb;p=platform%2Fkernel%2Flinux-rpi.git

nbd: quiesce request queues to make sure no submissions are 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>
---

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 977ec96..dea7d85 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");
 }