[2/2] blk-mq: start to freeze queue just after setting dying
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Message ID 1489064578-17305-4-git-send-email-tom.leiming@gmail.com
State New
Headers show

Commit Message

Ming Lei March 9, 2017, 1:02 p.m. UTC
Before commit 780db2071a(blk-mq: decouble blk-mq freezing
from generic bypassing), the dying flag is checked before
entering queue, and Tejun converts the checking into .mq_freeze_depth,
and assumes the counter is increased just after dying flag
is set. Unfortunately we doesn't do that in blk_set_queue_dying().

This patch calls blk_mq_freeze_queue_start() for blk-mq in
blk_set_queue_dying(), so that we can block new I/O coming
once the queue is set as dying.

Given blk_set_queue_dying() is always called in remove path
of block device, and queue will be cleaned up later, we don't
need to worry about undo of the counter.

Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
 block/blk-core.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

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diff --git a/block/blk-core.c b/block/blk-core.c
index 0eeb99ef654f..559487e58296 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -500,9 +500,12 @@  void blk_set_queue_dying(struct request_queue *q)
 	queue_flag_set(QUEUE_FLAG_DYING, q);
-	if (q->mq_ops)
+	if (q->mq_ops) {
-	else {
+		/* block new I/O coming */
+		blk_mq_freeze_queue_start(q);
+	} else {
 		struct request_list *rl;