4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Bart Van Assche <bart.vanass...@sandisk.com>
commit 1b856086813be9371929b6cc62045f9fd470f5a0 upstream.
blk_set_queue_dying() can be called while another thread is
submitting I/O or changing queue flags, e.g. through dm_stop_queue().
Hence protect the QUEUE_FLAG_DYING flag change with locking.
Signed-off-by: Bart Van Assche <bart.vanass...@sandisk.com>
Cc: Christoph Hellwig <h...@lst.de>
Cc: Mike Snitzer <snit...@redhat.com>
Signed-off-by: Jens Axboe <ax...@fb.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
block/blk-core.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -515,7 +515,9 @@ EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
void blk_set_queue_dying(struct request_queue *q)
{
- queue_flag_set_unlocked(QUEUE_FLAG_DYING, q);
+ spin_lock_irq(q->queue_lock);
+ queue_flag_set(QUEUE_FLAG_DYING, q);
+ spin_unlock_irq(q->queue_lock);
if (q->mq_ops)
blk_mq_wake_waiters(q);
