diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 739383c..322d18d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3274,12 +3274,14 @@
 	list_add(&s->memcg_params->list, &memcg->memcg_slab_caches);
 	mutex_unlock(&memcg->slab_caches_mutex);
 
-	root->memcg_params->memcg_caches[id] = s;
 	/*
-	 * the readers won't lock, make sure everybody sees the updated value,
-	 * so they won't put stuff in the queue again for no reason
+	 * Since readers won't lock (see cache_from_memcg_idx()), we need a
+	 * barrier here to ensure nobody will see the kmem_cache partially
+	 * initialized.
 	 */
-	wmb();
+	smp_wmb();
+
+	root->memcg_params->memcg_caches[id] = s;
 }
 
 void memcg_unregister_cache(struct kmem_cache *s)
@@ -3605,7 +3607,7 @@
 					  gfp_t gfp)
 {
 	struct mem_cgroup *memcg;
-	int idx;
+	struct kmem_cache *memcg_cachep;
 
 	VM_BUG_ON(!cachep->memcg_params);
 	VM_BUG_ON(!cachep->memcg_params->is_root_cache);
@@ -3619,15 +3621,9 @@
 	if (!memcg_can_account_kmem(memcg))
 		goto out;
 
-	idx = memcg_cache_id(memcg);
-
-	/*
-	 * barrier to mare sure we're always seeing the up to date value.  The
-	 * code updating memcg_caches will issue a write barrier to match this.
-	 */
-	read_barrier_depends();
-	if (likely(cache_from_memcg_idx(cachep, idx))) {
-		cachep = cache_from_memcg_idx(cachep, idx);
+	memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg));
+	if (likely(memcg_cachep)) {
+		cachep = memcg_cachep;
 		goto out;
 	}