block: wake up all tasks blocked in get_request()

Once blk_set_queue_dying() is done in blk_cleanup_queue(), we call
blk_freeze_queue() and wait for q->q_usage_counter becoming zero. But
if there are tasks blocked in get_request(), q->q_usage_counter can
never become zero. So we have to wake up all these tasks in
blk_set_queue_dying() first.

Fixes: 3ef28e83 ("block: generic request_queue reference counting")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-core.c

@@ -637,8 +637,8 @@ void blk_set_queue_dying(struct request_queue *q)
 		spin_lock_irq(q->queue_lock);
 		blk_queue_for_each_rl(rl, q) {
 			if (rl->rq_pool) {
-				wake_up(&rl->wait[BLK_RW_SYNC]);
-				wake_up(&rl->wait[BLK_RW_ASYNC]);
+				wake_up_all(&rl->wait[BLK_RW_SYNC]);
+				wake_up_all(&rl->wait[BLK_RW_ASYNC]);
 			}
 		}
 		spin_unlock_irq(q->queue_lock);