[PATCH 4.19 055/118] blk-mq: move cancel of requeue_work into blk_mq_release

[Greg Kroah-Hartman]

[ Upstream commit fbc2a15e3433058582e5635aabe48a3011a644a8 ]

With holding queue's kobject refcount, it is safe for driver
to schedule requeue. However, blk_mq_kick_requeue_list() may
be called after blk_sync_queue() is done because of concurrent
requeue activities, then requeue work may not be completed when
freeing queue, and kernel oops is triggered.

So moving the cancel of requeue_work into blk_mq_release() for
avoiding race between requeue and freeing queue.

Cc: Dongli Zhang <dongli.zhang@xxxxxxxxxx>
Cc: James Smart <james.smart@xxxxxxxxxxxx>
Cc: Bart Van Assche <bart.vanassche@xxxxxxx>
Cc: linux-scsi@xxxxxxxxxxxxxxx,
Cc: Martin K . Petersen <martin.petersen@xxxxxxxxxx>,
Cc: Christoph Hellwig <hch@xxxxxx>,
Cc: James E . J . Bottomley <jejb@xxxxxxxxxxxxxxxxxx>,
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Reviewed-by: Johannes Thumshirn <jthumshirn@xxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Tested-by: James Smart <james.smart@xxxxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 block/blk-core.c | 1 -
 block/blk-mq.c   | 2 ++
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 33488b1426b7..6eed5d84c2ef 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -411,7 +411,6 @@ void blk_sync_queue(struct request_queue *q)
 		struct blk_mq_hw_ctx *hctx;
 		int i;
 
-		cancel_delayed_work_sync(&q->requeue_work);
 		queue_for_each_hw_ctx(q, hctx, i)
 			cancel_delayed_work_sync(&hctx->run_work);
 	} else {
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 4e563ee462cb..70d839b9c3b0 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2465,6 +2465,8 @@ void blk_mq_release(struct request_queue *q)
 	struct blk_mq_hw_ctx *hctx;
 	unsigned int i;
 
+	cancel_delayed_work_sync(&q->requeue_work);
+
 	/* hctx kobj stays in hctx */
 	queue_for_each_hw_ctx(q, hctx, i) {
 		if (!hctx)
-- 
2.20.1