From: Daniel Wagner <dwagner@suse.de>
Date: Tue, 28 Jul 2020 15:29:51 +0200
Subject: block: Use non _rcu version of list functions for tag_set_list
Patch-mainline: v5.9-rc1
Git-commit: 08c875cbf481d74db82d6bba2fbcf580087dee24
References: git-fixes

tag_set_list is only accessed under the tag_set_lock lock. There is
no need for using the _rcu list functions.

The _rcu list function were introduced to allow read access to the
tag_set_list protected under RCU, see 705cda97ee3a ("blk-mq: Make it
safe to use RCU to iterate over blk_mq_tag_set.tag_list") and
05b79413946d ("Revert "blk-mq: don't handle TAG_SHARED in restart"").
Those changes got reverted later but the cleanup commit missed a
couple of places to undo the changes.

Fixes: 97889f9ac24f ("blk-mq: remove synchronize_rcu() from blk_mq_del_queue_tag_set()"
Signed-off-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 block/blk-mq.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2448,7 +2448,7 @@ static void blk_mq_del_queue_tag_set(str
 	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_SHARED;
@@ -2477,7 +2477,7 @@ static void blk_mq_add_queue_tag_set(str
 	}
 	if (set->flags & BLK_MQ_F_TAG_SHARED)
 		queue_set_hctx_shared(q, true);
-	list_add_tail_rcu(&q->tag_set_list, &set->tag_list);
+	list_add_tail(&q->tag_set_list, &set->tag_list);
 
 	mutex_unlock(&set->tag_list_lock);
 }