diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 2a4f77f..54ec172 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -30,6 +30,8 @@
 			    .cfq_leaf_weight = 2 * CFQ_WEIGHT_DEFAULT, };
 EXPORT_SYMBOL_GPL(blkcg_root);
 
+struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css;
+
 static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
 
 static bool blkcg_policy_enabled(struct request_queue *q,