diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index c2c75477a6b2..1f63fc834dc3 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -452,13 +452,6 @@ static void throtl_pd_reset_stats(struct blkg_policy_data *pd)
 static struct throtl_grp *throtl_lookup_tg(struct throtl_data *td,
 					   struct blkcg *blkcg)
 {
-	/*
-	 * This is the common case when there are no blkcgs.  Avoid lookup
-	 * in this case
-	 */
-	if (blkcg == &blkcg_root)
-		return td_root_tg(td);
-
 	return blkg_to_tg(blkg_lookup(blkcg, td->queue));
 }
 
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index d5b54aa50582..0609bce69f68 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -249,6 +249,9 @@ static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
 {
 	struct blkcg_gq *blkg;
 
+	if (blkcg == &blkcg_root)
+		return q->root_blkg;
+
 	blkg = rcu_dereference(blkcg->blkg_hint);
 	if (blkg && blkg->q == q)
 		return blkg;