dm rq: take request_queue lock while clearing QUEUE_FLAG_STOPPED
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.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 2f605f6..bd3ba97 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -73,15 +73,24 @@
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)
