2 files changed, 6 insertions, 4 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 60bb049b6106..a6809645d212 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -956,16 +956,16 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
 static struct cgroup_subsys_state *
 blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
 {
-        struct blkio_cgroup *blkcg, *parent_blkcg;
+        struct blkio_cgroup *blkcg;
+        struct cgroup *parent = cgroup->parent;
 
-        if (!cgroup->parent) {
+        if (!parent) {
                 blkcg = &blkio_root_cgroup;
                 goto done;
         }
 
         /* Currently we do not support hierarchy deeper than two level (0,1) */
-        parent_blkcg = cgroup_to_blkio_cgroup(cgroup->parent);
-        if (css_depth(&parent_blkcg->css) > 0)
+        if (parent != cgroup->top_cgroup)
                 return ERR_PTR(-EINVAL);
 
         blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index b1472bc2d49c..ed897b5ef315 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -3741,8 +3741,10 @@ static void *cfq_init_queue(struct request_queue *q)
          * to make sure that cfq_put_cfqg() does not try to kfree root group
          */
         atomic_set(&cfqg->ref, 1);
+        rcu_read_lock();
         blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd,
                                         0);
+        rcu_read_unlock();
 #endif
         /*
          * Not strictly needed (since RB_ROOT just clears the node and we