4.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Bart Van Assche <bart.vanass...@sandisk.com>
commit d15bb3a6467e102e60d954aadda5fb19ce6fd8ec upstream.
It is required to hold the queue lock when calling blk_run_queue_async()
to avoid that a race between blk_run_queue_async() and
blk_cleanup_queue() is triggered.
Signed-off-by: Bart Van Assche <bart.vanass...@sandisk.com>
Signed-off-by: Mike Snitzer <snit...@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/md/dm-rq.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -218,6 +218,9 @@ static void rq_end_stats(struct mapped_d
*/
static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
{
+ struct request_queue *q = md->queue;
+ unsigned long flags;
+
atomic_dec(&md->pending[rw]);
/* nudge anyone waiting on suspend queue */
@@ -230,8 +233,11 @@ static void rq_completed(struct mapped_d
* back into ->request_fn() could deadlock attempting to grab the
* queue lock again.
*/
- if (!md->queue->mq_ops && run_queue)
- blk_run_queue_async(md->queue);
+ if (!q->mq_ops && run_queue) {
+ spin_lock_irqsave(q->queue_lock, flags);
+ blk_run_queue_async(q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ }
/*
* dm_put() must be at the end of this function. See the comment above
