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Tue, 8 Oct 2024 11:29:31 +0800 Subject: Re: [PATCH 1/1] mm/slab: remove duplicate check in create_cache() To: Vlastimil Babka , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, , References: <20240821032637.1930-1-thunder.leizhen@huawei.com> <4dadf9be-a349-4a19-ae9c-652ade9e2198@suse.cz> From: "Leizhen (ThunderTown)" Message-ID: Date: Tue, 8 Oct 2024 11:29:31 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <4dadf9be-a349-4a19-ae9c-652ade9e2198@suse.cz> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemf100006.china.huawei.com (7.185.36.228) X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: E8A7C120005 X-Stat-Signature: g6jkt3d3ey8cksit7oogf737bjxecxte X-HE-Tag: 1728358177-337383 X-HE-Meta: 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 RFrrHrbm /AFXsbiSOo4KzUm1oYq0BkHGat0V6OMwb9rImN4Bx6rCbx7A+vRu6c4WkPa10b7GQlTIZ/B8XgVr7THVxrzsfSwTSSje4HtoBBsC54T0M9EsrWvSK0OEvCzxwbjTrLtaWw+Yc3G0m0fMt5LjVSfR9oGX1uPCffzndISN3/EgeHUbZwepOwT6HL06a+EXZT+1PpR5gPG0h8LVUlG/rJ9p5WhhRFjpkIQFS1GFUHk4591edX99KBX1vFN4gAHNZdCJaWOtBnIHyV0sHRQO/cGUkQJm0ig== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2024/10/2 20:09, Vlastimil Babka wrote: > On 8/21/24 05:26, Zhen Lei wrote: >> The WARN_ON() check in static function create_cache() is done by its only >> parent kmem_cache_create_usercopy() before calling it. >> if (... >> WARN_ON(size < usersize || size - usersize < useroffset)) >> usersize = useroffset = 0; >> ... >> s = create_cache(..., size, ..., useroffset, usersize, ...); >> >> Therefore, the WARN_ON() check in create_cache() can be safely removed. >> >> Signed-off-by: Zhen Lei > > Hi, sorry for the late reply. It doesn't matter, because the compiler will optimize it. It just saves the reader a little time. > This code was heavily refactored as of 6.12-rc1. Can you check if it's still > the case and send updated patch? It is still there. I'll post v2 later. > Thanks, > Vlastimil > >> --- >> mm/slab_common.c | 3 --- >> 1 file changed, 3 deletions(-) >> >> diff --git a/mm/slab_common.c b/mm/slab_common.c >> index 40b582a014b8f2f..3069c9095523484 100644 >> --- a/mm/slab_common.c >> +++ b/mm/slab_common.c >> @@ -210,9 +210,6 @@ static struct kmem_cache *create_cache(const char *name, >> struct kmem_cache *s; >> int err; >> >> - if (WARN_ON(useroffset + usersize > object_size)) >> - useroffset = usersize = 0; >> - >> err = -ENOMEM; >> s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); >> if (!s) > > . > -- Regards, Zhen Lei