2 files changed, 47 insertions, 38 deletions

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 28928ce9b07f..865e87c014d6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2984,43 +2984,6 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
 	return 0;
 }
 
-int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
-			     struct kmem_cache *root_cache)
-{
-	size_t size;
-
-	if (!memcg_kmem_enabled())
-		return 0;
-
-	if (!memcg) {
-		size = offsetof(struct memcg_cache_params, memcg_caches);
-		size += memcg_limited_groups_array_size * sizeof(void *);
-	} else
-		size = sizeof(struct memcg_cache_params);
-
-	s->memcg_params = kzalloc(size, GFP_KERNEL);
-	if (!s->memcg_params)
-		return -ENOMEM;
-
-	if (memcg) {
-		s->memcg_params->memcg = memcg;
-		s->memcg_params->root_cache = root_cache;
-		css_get(&memcg->css);
-	} else
-		s->memcg_params->is_root_cache = true;
-
-	return 0;
-}
-
-void memcg_free_cache_params(struct kmem_cache *s)
-{
-	if (!s->memcg_params)
-		return;
-	if (!s->memcg_params->is_root_cache)
-		css_put(&s->memcg_params->memcg->css);
-	kfree(s->memcg_params);
-}
-
 static void memcg_register_cache(struct mem_cgroup *memcg,
 				 struct kmem_cache *root_cache)
 {
@@ -3051,6 +3014,7 @@ static void memcg_register_cache(struct mem_cgroup *memcg,
 	if (!cachep)
 		return;
 
+	css_get(&memcg->css);
 	list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
 
 	/*
@@ -3084,6 +3048,9 @@ static void memcg_unregister_cache(struct kmem_cache *cachep)
 	list_del(&cachep->memcg_params->list);
 
 	kmem_cache_destroy(cachep);
+
+	/* drop the reference taken in memcg_register_cache */
+	css_put(&memcg->css);
 }
 
 /*
diff --git a/mm/slab_common.c b/mm/slab_common.c
index f206cb10a544..c2a8661f8b81 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -116,6 +116,38 @@ static inline int kmem_cache_sanity_check(const char *name, size_t size)
 #endif
 
 #ifdef CONFIG_MEMCG_KMEM
+static int memcg_alloc_cache_params(struct mem_cgroup *memcg,
+		struct kmem_cache *s, struct kmem_cache *root_cache)
+{
+	size_t size;
+
+	if (!memcg_kmem_enabled())
+		return 0;
+
+	if (!memcg) {
+		size = offsetof(struct memcg_cache_params, memcg_caches);
+		size += memcg_limited_groups_array_size * sizeof(void *);
+	} else
+		size = sizeof(struct memcg_cache_params);
+
+	s->memcg_params = kzalloc(size, GFP_KERNEL);
+	if (!s->memcg_params)
+		return -ENOMEM;
+
+	if (memcg) {
+		s->memcg_params->memcg = memcg;
+		s->memcg_params->root_cache = root_cache;
+	} else
+		s->memcg_params->is_root_cache = true;
+
+	return 0;
+}
+
+static void memcg_free_cache_params(struct kmem_cache *s)
+{
+	kfree(s->memcg_params);
+}
+
 int memcg_update_all_caches(int num_memcgs)
 {
 	struct kmem_cache *s;
@@ -141,7 +173,17 @@ out:
 	mutex_unlock(&slab_mutex);
 	return ret;
 }
-#endif
+#else
+static inline int memcg_alloc_cache_params(struct mem_cgroup *memcg,
+		struct kmem_cache *s, struct kmem_cache *root_cache)
+{
+	return 0;
+}
+
+static inline void memcg_free_cache_params(struct kmem_cache *s)
+{
+}
+#endif /* CONFIG_MEMCG_KMEM */
 
 /*
  * Find a mergeable slab cache