diff options
| author | Yosry Ahmed <yosryahmed@google.com> | 2024-03-16 01:58:03 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-04-25 20:55:43 -0700 |
| commit | 91b71e78b8e478e1a9af36b15ff1d38810572866 (patch) | |
| tree | 961fbe5545a50cf8fc0af4909ed5ac83f1657945 | |
| parent | 5b0a67008b0d608bb7585fe4c3c0c09d5ceaf1c9 (diff) | |
mm: memcg: add NULL check to obj_cgroup_put()
9 out of 16 callers perform a NULL check before calling obj_cgroup_put().
Move the NULL check in the function, similar to mem_cgroup_put(). The
unlikely() NULL check in current_objcg_update() was left alone to avoid
dropping the unlikey() annotation as this a fast path.
Link: https://lkml.kernel.org/r/20240316015803.2777252-1-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | include/linux/memcontrol.h | 3 | ||||
| -rw-r--r-- | kernel/bpf/memalloc.c | 6 | ||||
| -rw-r--r-- | mm/memcontrol.c | 18 | ||||
| -rw-r--r-- | mm/zswap.c | 3 |
4 files changed, 11 insertions, 19 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 394fd0a887ae..b6264796815d 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -818,7 +818,8 @@ static inline void obj_cgroup_get_many(struct obj_cgroup *objcg, static inline void obj_cgroup_put(struct obj_cgroup *objcg) { - percpu_ref_put(&objcg->refcnt); + if (objcg) + percpu_ref_put(&objcg->refcnt); } static inline bool mem_cgroup_tryget(struct mem_cgroup *memcg) diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index 550f02e2cb13..a546aba46d5d 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -759,8 +759,7 @@ void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma) rcu_in_progress += atomic_read(&c->call_rcu_ttrace_in_progress); rcu_in_progress += atomic_read(&c->call_rcu_in_progress); } - if (ma->objcg) - obj_cgroup_put(ma->objcg); + obj_cgroup_put(ma->objcg); destroy_mem_alloc(ma, rcu_in_progress); } if (ma->caches) { @@ -776,8 +775,7 @@ void bpf_mem_alloc_destroy(struct bpf_mem_alloc *ma) rcu_in_progress += atomic_read(&c->call_rcu_in_progress); } } - if (ma->objcg) - obj_cgroup_put(ma->objcg); + obj_cgroup_put(ma->objcg); destroy_mem_alloc(ma, rcu_in_progress); } } diff --git a/mm/memcontrol.c b/mm/memcontrol.c index fabce2b50c69..786c0fae6e30 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2369,8 +2369,7 @@ static void drain_local_stock(struct work_struct *dummy) clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); local_unlock_irqrestore(&memcg_stock.stock_lock, flags); - if (old) - obj_cgroup_put(old); + obj_cgroup_put(old); } /* @@ -3145,8 +3144,7 @@ static struct obj_cgroup *current_objcg_update(void) if (old) { old = (struct obj_cgroup *) ((unsigned long)old & ~CURRENT_OBJCG_UPDATE_FLAG); - if (old) - obj_cgroup_put(old); + obj_cgroup_put(old); old = NULL; } @@ -3418,8 +3416,7 @@ void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat, mod_objcg_mlstate(objcg, pgdat, idx, nr); local_unlock_irqrestore(&memcg_stock.stock_lock, flags); - if (old) - obj_cgroup_put(old); + obj_cgroup_put(old); } static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes) @@ -3546,8 +3543,7 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes, } local_unlock_irqrestore(&memcg_stock.stock_lock, flags); - if (old) - obj_cgroup_put(old); + obj_cgroup_put(old); if (nr_pages) obj_cgroup_uncharge_pages(objcg, nr_pages); @@ -5468,8 +5464,7 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) { int node; - if (memcg->orig_objcg) - obj_cgroup_put(memcg->orig_objcg); + obj_cgroup_put(memcg->orig_objcg); for_each_node(node) free_mem_cgroup_per_node_info(memcg, node); @@ -6620,8 +6615,7 @@ static void mem_cgroup_exit(struct task_struct *task) objcg = (struct obj_cgroup *) ((unsigned long)objcg & ~CURRENT_OBJCG_UPDATE_FLAG); - if (objcg) - obj_cgroup_put(objcg); + obj_cgroup_put(objcg); /* * Some kernel allocations can happen after this point, diff --git a/mm/zswap.c b/mm/zswap.c index 6f8850c44b61..2817e2791c13 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1618,8 +1618,7 @@ put_pool: freepage: zswap_entry_cache_free(entry); reject: - if (objcg) - obj_cgroup_put(objcg); + obj_cgroup_put(objcg); check_old: /* * If the zswap store fails or zswap is disabled, we must invalidate the |