memcg, slab: RCU protect memcg_params for root caches

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 80197e5..216659d 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3178,18 +3178,17 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
 
        if (num_groups > memcg_limited_groups_array_size) {
                int i;
+               struct memcg_cache_params *new_params;
                ssize_t size = memcg_caches_array_size(num_groups);
 
                size *= sizeof(void *);
                size += offsetof(struct memcg_cache_params, memcg_caches);
 
-               s->memcg_params = kzalloc(size, GFP_KERNEL);
-               if (!s->memcg_params) {
-                       s->memcg_params = cur_params;
+               new_params = kzalloc(size, GFP_KERNEL);
+               if (!new_params)
                        return -ENOMEM;
-               }
 
-               s->memcg_params->is_root_cache = true;
+               new_params->is_root_cache = true;
 
                /*
                 * There is the chance it will be bigger than
@@ -3203,7 +3202,7 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
                for (i = 0; i < memcg_limited_groups_array_size; i++) {
                        if (!cur_params->memcg_caches[i])
                                continue;
-                       s->memcg_params->memcg_caches[i] =
+                       new_params->memcg_caches[i] =
                                                cur_params->memcg_caches[i];
                }
 
@@ -3216,7 +3215,9 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
                 * bigger than the others. And all updates will reset this
                 * anyway.
                 */
-               kfree(cur_params);
+               rcu_assign_pointer(s->memcg_params, new_params);
+               if (cur_params)
+                       kfree_rcu(cur_params, rcu_head);
        }
        return 0;
 }