Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 22 Nov 2022 14:53:32 +0800
From:   Feng Tang <feng.tang@intel.com>
To:     Andrey Konovalov <andreyknvl@gmail.com>
CC:     Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        <linux-mm@kvack.org>, <kasan-dev@googlegroups.com>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -next 2/2] mm/kasan: simplify is_kmalloc check
Message-ID: <Y3xx7JUaRfRXRriw@feng-clx>
References: <20221121135024.1655240-1-feng.tang@intel.com>
 <20221121135024.1655240-2-feng.tang@intel.com>
 <CA+fCnZenKqb9_a2e5b25-DQ3uAKPgm=+tTDOP+D9c6wbDSjMNA@mail.gmail.com>
Content-Type: text/plain; charset="us-ascii"
Content-Disposition: inline
In-Reply-To: <CA+fCnZenKqb9_a2e5b25-DQ3uAKPgm=+tTDOP+D9c6wbDSjMNA@mail.gmail.com>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?hIxeKnFY2gxgO+p0c9raeW++/0CpT/W3JZRelGlJIO8BdiCIFRwic5bBlqLv?=
 =?us-ascii?Q?DcLR384e/bvaWNhh8IHx2wNY4Dao4dtGGQ1yB0ia15vZKeKTGku+Cbwf/uzq?=
 =?us-ascii?Q?s2gTSmKan1HIy4S8o+nEkmXTp69uKSgIa55Kb1tuim9jc/ZuPDG6Zuex4bW6?=
 =?us-ascii?Q?+J5Lm5F8Vip/nbmoFkDu0izm6gwa2NvV66y/akLbLpHW3jarafVmzyCrG0a8?=
 =?us-ascii?Q?Hi90QaaVSM+tQhWBD3vOCteyihvEtEPyWSWRU10cn7sIzZKLFDLx9elycE5a?=
 =?us-ascii?Q?Ry7xSd2l5VrUdRBMjxm+KlJVen0Bck+zdJ72CunewcwDfuYpS6SwBRk9zpwx?=
 =?us-ascii?Q?jYZ2Dk1Thei8TaGK8TDab6ur0mlLasBCKSLHaOByDHi1Z2VkWxFsPBymTxKT?=
 =?us-ascii?Q?mlAmeEx2WnwvRFNOdig34IIq/GN9H1WVJyazVg2snn2PQ6ZKmsgv4asEB/fH?=
 =?us-ascii?Q?362FxKWYBpkkgnz3K7cg/AjKbccoRk5trUVszhvxE/tOw9+8i9jB8NaZq/Kj?=
 =?us-ascii?Q?qouORsCXVktwTG3EMkYVsOgYPSxhhoeBHC/yY1ZaMGnrafS2KqreawvIfMy1?=
 =?us-ascii?Q?Jcw6z59BNcGquLGXh7Pc8nqWhLbt8HiHI41sLJpNbrDqQHqiwxQU7Wy0AoE2?=
 =?us-ascii?Q?xcO7C3YQWL6+kN1ZeamC6GpC+XQlWoR8jwStQMRXflHeM+k6EkcS1z8E9vCH?=
 =?us-ascii?Q?VyFADB0eJwCfI4mWMmu/UILzMSqWIOcp71M8BWfft+2MjKwVlAaQ6aiHpZW+?=
 =?us-ascii?Q?Tj72Hglhr0kSQe7hUl1Wx32smAFvxRsVQNHgrAc9oRKD8qliqUfnoVUOi5rv?=
 =?us-ascii?Q?2LuCr7Pzn4zC13NbeilpaKtdAaiUmMQdqewxRotSAE77vEpxClbO1+pe3ldl?=
 =?us-ascii?Q?fYjAY6fTRwNL2gGuIp9qstZnt01iKQ/QoUSYy6KQ8uqdiElWCKeZ5mcnIHI0?=
 =?us-ascii?Q?l53Ieq9U3jMGqaA6QhpG4DsR00NFMzZsod3r0ODTsRQWKqwScP+aTSjilYpm?=
 =?us-ascii?Q?Fq1NnR4Qa+KoU9qIQVQdqaQlUOLkfxlEe1qLRKNzNfKbJ3z0olrVEOKR2t9L?=
 =?us-ascii?Q?l8X9IMgHWWIIVA4uQ6VtlyT6Lte699uI19rzzyqyipC9Ahw6o56FeuNIQZgU?=
 =?us-ascii?Q?YhwAitKRNy6iqq5n/bLR6vFpyLWwu9NFlFbF5bGa6RAHc092EYlvf4j0OK4p?=
 =?us-ascii?Q?vEm62Hzbnu16eYnyvR8/Bb+L0sk7G9Lw+s4Ma+oPassSVjG+l6u50gDxdrlL?=
 =?us-ascii?Q?WyPPdn+CwcrlTQ82ShpaPVssofNxqS+DsQ0cafZT2FMNZINmJyh4PTrPmRpF?=
 =?us-ascii?Q?0+uthgP0WQp8NXWGMNnjF7wM4zZimoPwn6WZSDmG5irfcOQsaI1a+7pSWnOJ?=
 =?us-ascii?Q?TAQsnN10JW3LB/1ZJcANKIQz75DrCUi7vC42scdyYOSToDeRjX+aw22uwLdO?=
 =?us-ascii?Q?pRaGcedFwBVzgGRVaOjXs4pWTS9Gu2iLBLwAKVJaKi47vruF4SKn5RsFkHE2?=
 =?us-ascii?Q?RZc8OoPEqL6lHq+VPcAxF4UMtfYru610+Gg6r31EJtOtV06gfEDkrbkrIqEZ?=
 =?us-ascii?Q?W8+n+gokq9ZJm/+SDC6eMikU33EvhrowZSBiEAOP?=
X-MS-Exchange-CrossTenant-Network-Message-Id: 531281ac-428b-4016-f828-08dacc56b8a7
X-MS-Exchange-CrossTenant-AuthSource: MN0PR11MB6304.namprd11.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 22 Nov 2022 06:56:46.5178
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: MSavPj78hBtjSMiaE9iALkULkMUoDIxSKAbb2qa4GXNz+nb64rkFQ+deYLITeb9deh/LkUorNqZ3gmS544SMjQ==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA1PR11MB7366
X-OriginatorOrg: intel.com
X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,
        DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,
        SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Mon, Nov 21, 2022 at 04:15:32PM +0100, Andrey Konovalov wrote:
> On Mon, Nov 21, 2022 at 2:53 PM Feng Tang <feng.tang@intel.com> wrote:
> >
> > Use new is_kmalloc_cache() to simplify the code of checking whether
> > a kmem_cache is a kmalloc cache.
> >
> > Signed-off-by: Feng Tang <feng.tang@intel.com>
> 
> Hi Feng,
> 
> Nice simplification!
> 
> > ---
> >  include/linux/kasan.h | 9 ---------
> >  mm/kasan/common.c     | 9 ++-------
> >  mm/slab_common.c      | 1 -
> >  3 files changed, 2 insertions(+), 17 deletions(-)
> >
> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> > index dff604912687..fc46f5d6f404 100644
> > --- a/include/linux/kasan.h
> > +++ b/include/linux/kasan.h
> > @@ -102,7 +102,6 @@ struct kasan_cache {
> >         int alloc_meta_offset;
> >         int free_meta_offset;
> >  #endif
> > -       bool is_kmalloc;
> >  };
> 
> We can go even further here, and only define the kasan_cache struct
> and add the kasan_info field to kmem_cache when CONFIG_KASAN_GENERIC
> is enabled.

Good idea. thanks!

I mainly checked the kasan_cache related code, and make an add-on
patch below, please let me know if my understanding is wrong or I
missed anything.

Thanks,
Feng

---
diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index 0ac6505367ee..f2e41290094e 100644
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -96,14 +96,6 @@ static inline bool kasan_has_integrated_init(void)
 }
 
 #ifdef CONFIG_KASAN
-
-struct kasan_cache {
-#ifdef CONFIG_KASAN_GENERIC
-	int alloc_meta_offset;
-	int free_meta_offset;
-#endif
-};
-
 void __kasan_unpoison_range(const void *addr, size_t size);
 static __always_inline void kasan_unpoison_range(const void *addr, size_t size)
 {
@@ -293,6 +285,11 @@ static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
 
 #ifdef CONFIG_KASAN_GENERIC
 
+struct kasan_cache {
+	int alloc_meta_offset;
+	int free_meta_offset;
+};
+
 size_t kasan_metadata_size(struct kmem_cache *cache, bool in_object);
 slab_flags_t kasan_never_merge(void);
 void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index f0ffad6a3365..39f7f1f95de2 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -72,7 +72,7 @@ struct kmem_cache {
 	int obj_offset;
 #endif /* CONFIG_DEBUG_SLAB */
 
-#ifdef CONFIG_KASAN
+#ifdef CONFIG_KASAN_GENERIC
 	struct kasan_cache kasan_info;
 #endif
 
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index f9c68a9dac04..4e7cdada4bbb 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -132,7 +132,7 @@ struct kmem_cache {
 	unsigned int *random_seq;
 #endif
 
-#ifdef CONFIG_KASAN
+#ifdef CONFIG_KASAN_GENERIC
 	struct kasan_cache kasan_info;
 #endif