cgroups: Fix a lockdep warning at cgroup removal

Commit 2fd6b7f5 ("fs: dcache scale subdirs") forgot to annotate a dentry
lock, which caused a lockdep warning.

Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 51cddc11cd85..a7837e2d9d6b 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -912,7 +912,7 @@ static void cgroup_d_remove_dir(struct dentry *dentry)
 
         parent = dentry->d_parent;
         spin_lock(&parent->d_lock);
-        spin_lock(&dentry->d_lock);
+        spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
         list_del_init(&dentry->d_u.d_child);
         spin_unlock(&dentry->d_lock);
         spin_unlock(&parent->d_lock);