[PATCH 2/8] Revert "blk-mq: Make it safe to use RCU to iterate over blk_mq_tag_set.tag_list"

[Ming Lei]

This reverts commit a8a6ac7ad3fb6b84b933ca1ea5110998bdaeee17.

Signed-off-by: Ming Lei <ming.lei at redhat.com>
---
 block/blk-mq.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 7d2ea6357c7d..8b59f6b4ec8e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2947,7 +2947,7 @@ static void blk_mq_del_queue_tag_set(struct request_queue *q)
 	struct blk_mq_tag_set *set = q->tag_set;
 
 	mutex_lock(&set->tag_list_lock);
-	list_del_rcu(&q->tag_set_list);
+	list_del(&q->tag_set_list);
 	if (list_is_singular(&set->tag_list)) {
 		/* just transitioned to unshared */
 		set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
@@ -2955,11 +2955,7 @@ static void blk_mq_del_queue_tag_set(struct request_queue *q)
 		blk_mq_update_tag_set_shared(set, false);
 	}
 	mutex_unlock(&set->tag_list_lock);
-	/*
-	 * Calling synchronize_rcu() and INIT_LIST_HEAD(&q->tag_set_list) is
-	 * not necessary since blk_mq_del_queue_tag_set() is only called from
-	 * blk_cleanup_queue().
-	 */
+	INIT_LIST_HEAD(&q->tag_set_list);
 }
 
 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
-- 
2.29.2