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 @@ -23,49 +23,17 @@ enum slab_state slab_state; LIST_HEAD(slab_caches); DEFINE_MUTEX(slab_mutex); -/* - * kmem_cache_create - Create a cache. - * @name: A string which is used in /proc/slabinfo to identify this cache. - * @size: The size of objects to be created in this cache. - * @align: The required alignment for the objects. - * @flags: SLAB flags - * @ctor: A constructor for the objects. - * - * Returns a ptr to the cache on success, NULL on failure. - * Cannot be called within a interrupt, but can be interrupted. - * The @ctor is run when new pages are allocated by the cache. - * - * The flags are - * - * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) - * to catch references to uninitialised memory. - * - * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check - * for buffer overruns. - * - * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware - * cacheline. This can be beneficial if you're counting cycles as closely - * as davem. - */ - -struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align, - unsigned long flags, void (*ctor)(void *)) +#ifdef CONFIG_DEBUG_VM +static int kmem_cache_sanity_check(const char *name, size_t size) { 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; + pr_err("kmem_cache_create(%s) integrity check failed\n", name); + return -EINVAL; } -#endif - get_online_cpus(); - mutex_lock(&slab_mutex); - -#ifdef CONFIG_DEBUG_VM list_for_each_entry(s, &slab_caches, list) { char tmp; int res; @@ -77,36 +45,67 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align */ res = probe_kernel_address(s->name, tmp); if (res) { - printk(KERN_ERR - "Slab cache with size %d has lost its name\n", + pr_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); + pr_err("%s (%s): Cache name already exists.\n", + __func__, name); dump_stack(); s = NULL; - goto oops; + 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 - s = __kmem_cache_create(name, size, align, flags, ctor); +/* + * kmem_cache_create - Create a cache. + * @name: A string which is used in /proc/slabinfo to identify this cache. + * @size: The size of objects to be created in this cache. + * @align: The required alignment for the objects. + * @flags: SLAB flags + * @ctor: A constructor for the objects. + * + * Returns a ptr to the cache on success, NULL on failure. + * Cannot be called within a interrupt, but can be interrupted. + * The @ctor is run when new pages are allocated by the cache. + * + * The flags are + * + * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) + * to catch references to uninitialised memory. + * + * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check + * for buffer overruns. + * + * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware + * cacheline. This can be beneficial if you're counting cycles as closely + * as davem. + */ + +struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align, + unsigned long flags, void (*ctor)(void *)) +{ + struct kmem_cache *s = NULL; -#ifdef CONFIG_DEBUG_VM -oops: -#endif + get_online_cpus(); + mutex_lock(&slab_mutex); + 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); -- 2.34.1