diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 6f1bfdf..8c520fa 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -97,7 +97,6 @@
 	/* service tree for active throtl groups */
 	struct throtl_rb_root tg_service_tree;
 
-	struct throtl_grp *root_tg;
 	struct request_queue *queue;
 
 	/* Total Number of queued bios on READ and WRITE lists */
@@ -131,6 +130,11 @@
 	return pdata_to_blkg(tg);
 }
 
+static inline struct throtl_grp *td_root_tg(struct throtl_data *td)
+{
+	return blkg_to_tg(td->queue->root_blkg);
+}
+
 enum tg_state_flags {
 	THROTL_TG_FLAG_on_rr = 0,	/* on round-robin busy list */
 };
@@ -261,7 +265,7 @@
 	 * Avoid lookup in this case
 	 */
 	if (blkcg == &blkio_root_cgroup)
-		return td->root_tg;
+		return td_root_tg(td);
 
 	return blkg_to_tg(blkg_lookup(blkcg, td->queue));
 }
@@ -277,7 +281,7 @@
 	 * Avoid lookup in this case
 	 */
 	if (blkcg == &blkio_root_cgroup) {
-		tg = td->root_tg;
+		tg = td_root_tg(td);
 	} else {
 		struct blkio_group *blkg;
 
@@ -287,7 +291,7 @@
 		if (!IS_ERR(blkg))
 			tg = blkg_to_tg(blkg);
 		else if (!blk_queue_dead(q))
-			tg = td->root_tg;
+			tg = td_root_tg(td);
 	}
 
 	return tg;
@@ -1245,12 +1249,12 @@
 
 	blkg = blkg_lookup_create(&blkio_root_cgroup, q, true);
 	if (!IS_ERR(blkg))
-		td->root_tg = blkg_to_tg(blkg);
+		q->root_blkg = blkg;
 
 	spin_unlock_irq(q->queue_lock);
 	rcu_read_unlock();
 
-	if (!td->root_tg) {
+	if (!q->root_blkg) {
 		kfree(td);
 		return -ENOMEM;
 	}
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index de95f9a..86440e0 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3964,8 +3964,10 @@
 	spin_lock_irq(q->queue_lock);
 
 	blkg = blkg_lookup_create(&blkio_root_cgroup, q, true);
-	if (!IS_ERR(blkg))
+	if (!IS_ERR(blkg)) {
+		q->root_blkg = blkg;
 		cfqd->root_group = blkg_to_cfqg(blkg);
+	}
 
 	spin_unlock_irq(q->queue_lock);
 	rcu_read_unlock();
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index d2c69f8..b01c377 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -31,6 +31,7 @@
 struct request;
 struct sg_io_hdr;
 struct bsg_job;
+struct blkio_group;
 
 #define BLKDEV_MIN_RQ	4
 #define BLKDEV_MAX_RQ	128	/* Default maximum */
@@ -369,6 +370,7 @@
 
 	struct list_head	icq_list;
 #ifdef CONFIG_BLK_CGROUP
+	struct blkio_group	*root_blkg;
 	struct list_head	blkg_list;
 #endif