diff options
| -rw-r--r-- | kernel/cgroup.c | 2 | ||||
| -rw-r--r-- | mm/memcontrol.c | 24 |
2 files changed, 9 insertions, 17 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index a220fdb66568..59aa339a245c 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -5451,7 +5451,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry, struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss) { WARN_ON_ONCE(!rcu_read_lock_held()); - return idr_find(&ss->css_idr, id); + return id > 0 ? idr_find(&ss->css_idr, id) : NULL; } #ifdef CONFIG_CGROUP_DEBUG diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c3f09b2dda5f..0a06628470cc 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -460,6 +460,12 @@ static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg) return memcg->css.id; } +/* + * A helper function to get mem_cgroup from ID. must be called under + * rcu_read_lock(). The caller is responsible for calling + * css_tryget_online() if the mem_cgroup is used for charging. (dropping + * refcnt from swap can be called against removed memcg.) + */ static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id) { struct cgroup_subsys_state *css; @@ -2349,20 +2355,6 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) } /* - * A helper function to get mem_cgroup from ID. must be called under - * rcu_read_lock(). The caller is responsible for calling - * css_tryget_online() if the mem_cgroup is used for charging. (dropping - * refcnt from swap can be called against removed memcg.) - */ -static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) -{ - /* ID 0 is unused ID */ - if (!id) - return NULL; - return mem_cgroup_from_id(id); -} - -/* * try_get_mem_cgroup_from_page - look up page's memcg association * @page: the page * @@ -2388,7 +2380,7 @@ struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) ent.val = page_private(page); id = lookup_swap_cgroup_id(ent); rcu_read_lock(); - memcg = mem_cgroup_lookup(id); + memcg = mem_cgroup_from_id(id); if (memcg && !css_tryget_online(&memcg->css)) memcg = NULL; rcu_read_unlock(); @@ -5869,7 +5861,7 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry) id = swap_cgroup_record(entry, 0); rcu_read_lock(); - memcg = mem_cgroup_lookup(id); + memcg = mem_cgroup_from_id(id); if (memcg) { if (!mem_cgroup_is_root(memcg)) page_counter_uncharge(&memcg->memsw, 1); |