diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3108150e47b1..fa943843a32f 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -6166,7 +6166,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
 struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
 {
 	WARN_ON_ONCE(!rcu_read_lock_held());
-	return id > 0 ? idr_find(&ss->css_idr, id) : NULL;
+	return idr_find(&ss->css_idr, id);
 }
 
 /**