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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id E73C1C433EF for ; Tue, 12 Jun 2018 12:18:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A66BA2086D for ; Tue, 12 Jun 2018 12:18:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A66BA2086D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933659AbeFLMSu convert rfc822-to-8bit (ORCPT ); Tue, 12 Jun 2018 08:18:50 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:38380 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932412AbeFLMSt (ORCPT ); Tue, 12 Jun 2018 08:18:49 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2C4B54021CC2; Tue, 12 Jun 2018 12:18:49 +0000 (UTC) Received: from 117.195.187.81.in-addr.arpa (unknown [10.33.36.20]) by smtp.corp.redhat.com (Postfix) with ESMTP id D1FEC178BC; Tue, 12 Jun 2018 12:18:45 +0000 (UTC) Subject: Re: [Cluster-devel] [PATCH] gfs2: add error handling for kmem_cache_zalloc To: "cgxu519@gmx.com" , Zhouyang Jia Cc: cluster-devel@redhat.com, linux-kernel@vger.kernel.org References: <1528774692-38990-1-git-send-email-jiazhouyang09@gmail.com> From: Steven Whitehouse Message-ID: Date: Tue, 12 Jun 2018 13:18:44 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 8BIT Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Tue, 12 Jun 2018 12:18:49 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Tue, 12 Jun 2018 12:18:49 +0000 (UTC) for IP:'10.11.54.5' DOMAIN:'int-mx05.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'swhiteho@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 12/06/18 08:24, cgxu519@gmx.com wrote: >> 在 2018年6月12日，上午11:38，Zhouyang Jia 写道： >> >> When kmem_cache_zalloc fails, the lack of error-handling code may >> cause unexpected results. >> >> This patch adds error-handling code after calling kmem_cache_zalloc. > Should not fail on this case. > > Thanks, > Chengguang. Indeed. It is one of the few GFP_NOFAIL allocations left in GFS2. It would be good to figure out how to remove the last few of these allocations, but simply adding a check for a NULL return is not the right solution here anyway. I would also add that if this problem was easier then I'm sure we'd have solved it before - the right answer is not very obvious in this case, Steve. > >> Signed-off-by: Zhouyang Jia >> --- >> fs/gfs2/trans.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c >> index 064c9a0..da81eb4 100644 >> --- a/fs/gfs2/trans.c >> +++ b/fs/gfs2/trans.c >> @@ -130,6 +130,9 @@ static struct gfs2_bufdata *gfs2_alloc_bufdata(struct gfs2_glock *gl, >> struct gfs2_bufdata *bd; >> >> bd = kmem_cache_zalloc(gfs2_bufdata_cachep, GFP_NOFS | __GFP_NOFAIL); >> + if (!bd) >> + return NULL; >> + >> bd->bd_bh = bh; >> bd->bd_gl = gl; >> bd->bd_ops = lops; >> -- >> 2.7.4 >> >