diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 51fc803c999d..85bd46e0a745 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -876,6 +876,12 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 			goto fail;
 		}
 
+		if (radix_tree_preload(GFP_KERNEL)) {
+			blkg_free(new_blkg);
+			ret = -ENOMEM;
+			goto fail;
+		}
+
 		rcu_read_lock();
 		spin_lock_irq(q->queue_lock);
 
@@ -883,7 +889,7 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 		if (IS_ERR(blkg)) {
 			ret = PTR_ERR(blkg);
 			blkg_free(new_blkg);
-			goto fail_unlock;
+			goto fail_preloaded;
 		}
 
 		if (blkg) {
@@ -892,10 +898,12 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
 			blkg = blkg_create(pos, q, new_blkg);
 			if (unlikely(IS_ERR(blkg))) {
 				ret = PTR_ERR(blkg);
-				goto fail_unlock;
+				goto fail_preloaded;
 			}
 		}
 
+		radix_tree_preload_end();
+
 		if (pos == blkcg)
 			goto success;
 	}
@@ -905,6 +913,8 @@ success:
 	ctx->body = body;
 	return 0;
 
+fail_preloaded:
+	radix_tree_preload_end();
 fail_unlock:
 	spin_unlock_irq(q->queue_lock);
 	rcu_read_unlock();