From 3965fc3652244651006ebb31c8c45318ce84818f Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Thu, 23 Jan 2014 15:52:55 -0800 Subject: [PATCH] slab: clean up kmem_cache_create_memcg() error handling Currently kmem_cache_create_memcg() backoffs on failure inside conditionals, without using gotos. This results in the rollback code duplication, which makes the function look cumbersome even though on error we should only free the allocated cache. Since in the next patch I am going to add yet another rollback function call on error path there, let's employ labels instead of conditionals for undoing any changes on failure to keep things clean. Signed-off-by: Vladimir Davydov Reviewed-by: Pekka Enberg Cc: Michal Hocko Cc: Glauber Costa Cc: Johannes Weiner Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab_common.c | 65 +++++++++++++++++++++++------------------------- 1 file changed, 31 insertions(+), 34 deletions(-) diff --git a/mm/slab_common.c b/mm/slab_common.c index 0b7bb399b0e4..f70df3ef6f1a 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -171,13 +171,14 @@ kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size, struct kmem_cache *parent_cache) { struct kmem_cache *s = NULL; - int err = 0; + int err; get_online_cpus(); mutex_lock(&slab_mutex); - if (!kmem_cache_sanity_check(memcg, name, size) == 0) - goto out_locked; + err = kmem_cache_sanity_check(memcg, name, size); + if (err) + goto out_unlock; /* * Some allocators will constraint the set of valid flags to a subset @@ -189,45 +190,38 @@ kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size, s = __kmem_cache_alias(memcg, name, size, align, flags, ctor); if (s) - goto out_locked; + goto out_unlock; + err = -ENOMEM; s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); - if (s) { - s->object_size = s->size = size; - s->align = calculate_alignment(flags, align, size); - s->ctor = ctor; + if (!s) + goto out_unlock; - if (memcg_register_cache(memcg, s, parent_cache)) { - kmem_cache_free(kmem_cache, s); - err = -ENOMEM; - goto out_locked; - } + s->object_size = s->size = size; + s->align = calculate_alignment(flags, align, size); + s->ctor = ctor; - s->name = kstrdup(name, GFP_KERNEL); - if (!s->name) { - kmem_cache_free(kmem_cache, s); - err = -ENOMEM; - goto out_locked; - } + s->name = kstrdup(name, GFP_KERNEL); + if (!s->name) + goto out_free_cache; - err = __kmem_cache_create(s, flags); - if (!err) { - s->refcount = 1; - list_add(&s->list, &slab_caches); - memcg_cache_list_add(memcg, s); - } else { - kfree(s->name); - kmem_cache_free(kmem_cache, s); - } - } else - err = -ENOMEM; + err = memcg_register_cache(memcg, s, parent_cache); + if (err) + goto out_free_cache; + + err = __kmem_cache_create(s, flags); + if (err) + goto out_free_cache; + + s->refcount = 1; + list_add(&s->list, &slab_caches); + memcg_cache_list_add(memcg, s); -out_locked: +out_unlock: mutex_unlock(&slab_mutex); put_online_cpus(); if (err) { - if (flags & SLAB_PANIC) panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n", name, err); @@ -236,11 +230,14 @@ kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size, name, err); dump_stack(); } - return NULL; } - return s; + +out_free_cache: + kfree(s->name); + kmem_cache_free(kmem_cache, s); + goto out_unlock; } struct kmem_cache * -- GitLab