From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37F0EC352A3 for ; Thu, 13 Feb 2020 04:51:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0DB412082F for ; Thu, 13 Feb 2020 04:51:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729475AbgBMEva (ORCPT ); Wed, 12 Feb 2020 23:51:30 -0500 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:45761 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727076AbgBMEv3 (ORCPT ); Wed, 12 Feb 2020 23:51:29 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R671e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04455;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0TpsO4JW_1581569484; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TpsO4JW_1581569484) by smtp.aliyun-inc.com(127.0.0.1); Thu, 13 Feb 2020 12:51:25 +0800 Subject: Re: [PATCH 1/2] mm: vmpressure: don't need call kfree if kstrndup fails To: Andrew Morton Cc: David Hildenbrand , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1581398649-125989-1-git-send-email-yang.shi@linux.alibaba.com> <48d53caf-4b89-69c3-cf9b-47b8627db0bd@linux.alibaba.com> <20200212204827.df1de9015a3c03c79a8d7155@linux-foundation.org> From: Yang Shi Message-ID: Date: Wed, 12 Feb 2020 20:51:22 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <20200212204827.df1de9015a3c03c79a8d7155@linux-foundation.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/12/20 8:48 PM, Andrew Morton wrote: > On Wed, 12 Feb 2020 19:14:27 -0800 Yang Shi wrote: > >> On 2/12/20 3:21 AM, David Hildenbrand wrote: >>> On 11.02.20 06:24, Yang Shi wrote: >>>> When kstrndup fails (returns NULL) there is no memory is allocated by >>>> kmalloc, so no need to call kfree(). >>> "When kstrndup fails, no memory was allocated and we can exit directly." >> Thanks for correcting the commit log. >> >> Andrew, do you prefer I send an updated version or you would just update >> the patch in -mm tree? > I have already done this. Thanks! > > From: Yang Shi > Subject: mm: vmpressure: don't need call kfree if kstrndup fails > > When kstrndup fails, no memory was allocated and we can exit directly. > > [david@redhat.com: reword changelog] > Link: http://lkml.kernel.org/r/1581398649-125989-1-git-send-email-yang.shi@linux.alibaba.com > Signed-off-by: Yang Shi > Reviewed-by: Andrew Morton > Reviewed-by: David Hildenbrand > Acked-by: David Rientjes > Signed-off-by: Andrew Morton > --- > > mm/vmpressure.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > --- a/mm/vmpressure.c~mm-vmpressure-dont-need-call-kfree-if-kstrndup-fails > +++ a/mm/vmpressure.c > @@ -371,10 +371,8 @@ int vmpressure_register_event(struct mem > int ret = 0; > > spec_orig = spec = kstrndup(args, MAX_VMPRESSURE_ARGS_LEN, GFP_KERNEL); > - if (!spec) { > - ret = -ENOMEM; > - goto out; > - } > + if (!spec) > + return -ENOMEM; > > /* Find required level */ > token = strsep(&spec, ","); > _