From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932228Ab2HFPO7 (ORCPT ); Mon, 6 Aug 2012 11:14:59 -0400 Received: from g1t0026.austin.hp.com ([15.216.28.33]:20441 "EHLO g1t0026.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932081Ab2HFPO6 (ORCPT ); Mon, 6 Aug 2012 11:14:58 -0400 Message-ID: <1344266096.2486.17.camel@lorien2> Subject: [PATCH RESEND] mm: Restructure kmem_cache_create() to move debug cache integrity checks into a new function From: Shuah Khan Reply-To: shuah.khan@hp.com To: Pekka Enberg Cc: cl@linux.com, glommer@parallels.com, js1304@gmail.com, linux-mm@kvack.org, LKML , Andrew Morton , Linus Torvalds , David Rientjes , shuahkhan@gmail.com Date: Mon, 06 Aug 2012 09:14:56 -0600 In-Reply-To: <1344224494.3053.5.camel@lorien2> References: <1342221125.17464.8.camel@lorien2> <1344224494.3053.5.camel@lorien2> Organization: ISS-Linux Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Signed-off-by: Shuah Khan --- mm/slab_common.c | 74 ++++++++++++++++++++++++++++-------------------------- 1 file changed, 38 insertions(+), 36 deletions(-) diff --git a/mm/slab_common.c b/mm/slab_common.c index 12637ce..08bc2a4 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -23,6 +23,41 @@ enum slab_state slab_state; LIST_HEAD(slab_caches); DEFINE_MUTEX(slab_mutex); +static int kmem_cache_sanity_check(const char *name, size_t size) +{ +#ifdef CONFIG_DEBUG_VM + struct kmem_cache *s = NULL; + + 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 */ +#endif + return 0; +} + /* * kmem_cache_create - Create a cache. * @name: A string which is used in /proc/slabinfo to identify this cache. @@ -53,48 +88,17 @@ 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); + pr_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 + if (kmem_cache_sanity_check(name, size)) + goto oops; s = __kmem_cache_create(name, size, align, flags, ctor); @@ -102,9 +106,7 @@ oops: 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); -- 1.7.9.5