block: fix leak of q->rq_wb

CONFIG_DEBUG_TEST_DRIVER_REMOVE found a possible leak of q->rq_wb when a request queue is reregistered. This has been a problem since wbt was introduced, but the WARN_ON(!list_empty(&stats->callbacks)) in the blk-stat rework exposed it. Fix it by cleaning up wbt when we unregister the queue. Fixes: 87760e5 ("block: hook up writeback throttling") Signed-off-by: Omar Sandoval <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
ambv · Mar 29, 2017 · 02ba889 · 02ba889
1 parent 0c9539a
commit 02ba889
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
@@ -795,7 +795,6 @@ static void blk_release_queue(struct kobject *kobj)
 	struct request_queue *q =
 		container_of(kobj, struct request_queue, kobj);
 
-	wbt_exit(q);
 	if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags))
 		blk_stat_remove_callback(q, q->poll_cb);
 	blk_stat_free_callback(q->poll_cb);
@@ -938,6 +937,9 @@ void blk_unregister_queue(struct gendisk *disk)
 
 	queue_flag_clear_unlocked(QUEUE_FLAG_REGISTERED, q);
 
+	wbt_exit(q);
+
+
 	if (q->mq_ops)
 		blk_mq_unregister_dev(disk_to_dev(disk), q);