blkio: Initialize blkg->stats_lock for the root cfqg too

This fixes the lockdep warning reported by Gui Jianfeng.

Signed-off-by: Divyesh Shah <dpshah@google.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 1 insertions, 6 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 80c1261a7d38..83930f65016a 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -86,12 +86,6 @@ struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
 }
 EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
 
-void blkio_group_init(struct blkio_group *blkg)
-{
-        spin_lock_init(&blkg->stats_lock);
-}
-EXPORT_SYMBOL_GPL(blkio_group_init);
-
 /*
  * Add to the appropriate stat variable depending on the request type.
  * This should be called with the blkg->stats_lock held.
@@ -349,6 +343,7 @@ void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
         unsigned long flags;
 
         spin_lock_irqsave(&blkcg->lock, flags);
+        spin_lock_init(&blkg->stats_lock);
         rcu_assign_pointer(blkg->key, key);
         blkg->blkcg_id = css_id(&blkcg->css);
         hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);