Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752326Ab2HLRqP (ORCPT ); Sun, 12 Aug 2012 13:46:15 -0400 Received: from a194-183.smtp-out.amazonses.com ([199.255.194.183]:57632 "EHLO a194-183.smtp-out.amazonses.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750852Ab2HLRpz convert rfc822-to-8bit (ORCPT ); Sun, 12 Aug 2012 13:45:55 -0400 X-Greylist: delayed 562 seconds by postgrey-1.27 at vger.kernel.org; Sun, 12 Aug 2012 13:45:55 EDT Subject: Re: [PATCH v3] mm: Restructure kmem_cache_create() to move debug cache integrity checks into a new function References: <1342221125.17464.8.camel@lorien2> <1344224494.3053.5.camel@lorien2> <1344266096.2486.17.camel@lorien2> <1344272614.2486.40.camel@lorien2> <1344287631.2486.57.camel@lorien2> <1344531695.2393.27.camel@lorien2> <1344540801.2393.42.camel@lorien2> <1344789618.5128.5.camel@lorien2> From: Christoph Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset=us-ascii In-Reply-To: <1344789618.5128.5.camel@lorien2> Message-Id: <000001391be89602-3ef322de-204d-4d93-9f13-38065ce8f757-000000@email.amazonses.com> Date: Sun, 12 Aug 2012 17:36:31 +0000 Cc: "penberg@kernel.org" , "glommer@parallels.com" , "js1304@gmail.com" , DavidRientjes , "linux-mm@kvack.org" , LKML , Andrew Morton , Linus Torvalds , "shuahkhan@gmail.com" To: "shuah.khan@hp.com" Mime-Version: 1.0 (1.0) X-Mailer: iPad Mail (9B206) X-SES-Outgoing: 199.255.194.183 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4711 Lines: 149 Acked-by: Christoph Lameter On Aug 12, 2012, at 11:40, Shuah Khan wrote: > 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 | 90 +++++++++++++++++++++++++++++------------------------- > 1 file changed, 48 insertions(+), 42 deletions(-) > > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 12637ce..44facdf 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. > @@ -53,48 +99,11 @@ 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 > + if (kmem_cache_sanity_check(name, size)) > + goto oops; > > s = __kmem_cache_create(name, size, align, flags, ctor); > > @@ -102,9 +111,6 @@ 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 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/