4.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mike Snitzer <snit...@redhat.com>
commit 9dbeaeabacb26260d1621fe58f0f6fdedc8860d4 upstream.
Every call of queue_flag_clear_unlocked() after block device
initialization has finished is wrong if blk_cleanup_queue() can be
called concurrently. Convert queue_flag_clear_unlocked() into
queue_flag_clear() and protect it by the block layer queue lock.
Also, factor out dm_mq_start_queue().
Reported-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 | 19 ++++++++++++++-----
1 file changed, 14 insertions(+), 5 deletions(-)
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -73,15 +73,24 @@ static void dm_old_start_queue(struct re
spin_unlock_irqrestore(q->queue_lock, flags);
}
+static void dm_mq_start_queue(struct request_queue *q)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ queue_flag_clear(QUEUE_FLAG_STOPPED, q);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ blk_mq_start_stopped_hw_queues(q, true);
+ blk_mq_kick_requeue_list(q);
+}
+
void dm_start_queue(struct request_queue *q)
{
if (!q->mq_ops)
dm_old_start_queue(q);
- else {
- queue_flag_clear_unlocked(QUEUE_FLAG_STOPPED, q);
- blk_mq_start_stopped_hw_queues(q, true);
- blk_mq_kick_requeue_list(q);
- }
+ else
+ dm_mq_start_queue(q);
}
static void dm_old_stop_queue(struct request_queue *q)
