From 77be4b1366c97b95bb197e18187ff45b0e4f6bd3 Mon Sep 17 00:00:00 2001 From: Shuah Khan Date: Thu, 16 Aug 2012 00:09:46 -0700 Subject: [PATCH] mm/slab: restructure kmem_cache_create() debug checks kmem_cache_create() does cache integrity checks when CONFIG_DEBUG_VM is defined. These checks interspersed with the regular code path has lead to compile time warnings when compiled without CONFIG_DEBUG_VM defined. Restructuring the code to move the integrity checks in to a new function would eliminate the current compile warning problem and also will allow for future changes to the debug only code to evolve without introducing new warnings in the regular path. This restructuring work is based on the discussion in the following thread: https://lkml.org/lkml/2012/7/13/424 [akpm@linux-foundation.org: fix build, cleanup] Signed-off-by: Shuah Khan Acked-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Pekka Enberg --- mm/slab_common.c | 97 ++++++++++++++++++++++++------------------------ 1 file changed, 48 insertions(+), 49 deletions(-) diff --git a/mm/slab_common.c b/mm/slab_common.c index aa3ca5bb01b5..8cf8b4962d6c 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -23,6 +23,52 @@ enum slab_state slab_state; LIST_HEAD(slab_caches); DEFINE_MUTEX(slab_mutex); +#ifdef CONFIG_DEBUG_VM +static int kmem_cache_sanity_check(const char *name, size_t size) +{ + struct kmem_cache *s = NULL; + + if (!name || in_interrupt() || size < sizeof(void *) || + size > KMALLOC_MAX_SIZE) { + pr_err("kmem_cache_create(%s) integrity check failed\n", name); + return -EINVAL; + } + + list_for_each_entry(s, &slab_caches, list) { + char tmp; + int res; + + /* + * This happens when the module gets unloaded and doesn't + * destroy its slab cache and no-one else reuses the vmalloc + * area of the module. Print a warning. + */ + res = probe_kernel_address(s->name, tmp); + if (res) { + pr_err("Slab cache with size %d has lost its name\n", + s->object_size); + continue; + } + + if (!strcmp(s->name, name)) { + pr_err("%s (%s): Cache name already exists.\n", + __func__, name); + dump_stack(); + s = NULL; + return -EINVAL; + } + } + + WARN_ON(strchr(name, ' ')); /* It confuses parsers */ + return 0; +} +#else +static inline int kmem_cache_sanity_check(const char *name, size_t size) +{ + return 0; +} +#endif + /* * kmem_cache_create - Create a cache. * @name: A string which is used in /proc/slabinfo to identify this cache. @@ -53,60 +99,13 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align { struct kmem_cache *s = NULL; -#ifdef CONFIG_DEBUG_VM - if (!name || in_interrupt() || size < sizeof(void *) || - size > KMALLOC_MAX_SIZE) { - printk(KERN_ERR "kmem_cache_create(%s) integrity check" - " failed\n", name); - goto out; - } -#endif - get_online_cpus(); mutex_lock(&slab_mutex); - -#ifdef CONFIG_DEBUG_VM - list_for_each_entry(s, &slab_caches, list) { - char tmp; - int res; - - /* - * This happens when the module gets unloaded and doesn't - * destroy its slab cache and no-one else reuses the vmalloc - * area of the module. Print a warning. - */ - res = probe_kernel_address(s->name, tmp); - if (res) { - printk(KERN_ERR - "Slab cache with size %d has lost its name\n", - s->object_size); - continue; - } - - if (!strcmp(s->name, name)) { - printk(KERN_ERR "kmem_cache_create(%s): Cache name" - " already exists.\n", - name); - dump_stack(); - s = NULL; - goto oops; - } - } - - WARN_ON(strchr(name, ' ')); /* It confuses parsers */ -#endif - - s = __kmem_cache_create(name, size, align, flags, ctor); - -#ifdef CONFIG_DEBUG_VM -oops: -#endif + if (kmem_cache_sanity_check(name, size) == 0) + s = __kmem_cache_create(name, size, align, flags, ctor); mutex_unlock(&slab_mutex); put_online_cpus(); -#ifdef CONFIG_DEBUG_VM -out: -#endif if (!s && (flags & SLAB_PANIC)) panic("kmem_cache_create: Failed to create slab '%s'\n", name);