Each caller of memcg_cache_id ends up sanitizing its parameters in its own way.
Now that the memcg_cache_id itself is more robust, we can consolidate this.
There are callers that really cannot handle anything other than a valid memcg
being passed to the function, otherwise something is seriously wrong. In those
cases, we at least VM_BUG_ON explicitly before using the value any further
Signed-off-by: Glauber Costa <glommer@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
mm/memcontrol.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 359a53b..adbc09b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2975,10 +2975,14 @@ static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
{
struct kmem_cache *cachep;
+ int idx;
VM_BUG_ON(p->is_root_cache);
cachep = p->root_cache;
- return cachep->memcg_params->memcg_caches[memcg_cache_id(p->memcg)];
+
+ idx = memcg_cache_id(p->memcg);
+ VM_BUG_ON(idx < 0);
+ return cachep->memcg_params->memcg_caches[idx];
}
#ifdef CONFIG_SLABINFO
@@ -3246,6 +3250,7 @@ void memcg_release_cache(struct kmem_cache *s)
memcg = s->memcg_params->memcg;
id = memcg_cache_id(memcg);
+ VM_BUG_ON(id < 0);
root = s->memcg_params->root_cache;
root->memcg_params->memcg_caches[id] = NULL;
@@ -3408,9 +3413,8 @@ static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
struct kmem_cache *new_cachep;
int idx;
- BUG_ON(!memcg_can_account_kmem(memcg));
-
idx = memcg_cache_id(memcg);
+ BUG_ON(!idx < 0);
mutex_lock(&memcg_cache_mutex);
new_cachep = cachep->memcg_params->memcg_caches[idx];
@@ -3583,10 +3587,9 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
rcu_read_lock();
memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
- if (!memcg_can_account_kmem(memcg))
- goto out;
-
idx = memcg_cache_id(memcg);
+ if (idx < 0)
+ return cachep;
/*
* barrier to mare sure we're always seeing the up to date value. The
--
1.8.1.4
--
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