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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 E7D25ECE560 for ; Wed, 26 Sep 2018 13:58:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ACA9D214C5 for ; Wed, 26 Sep 2018 13:58:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ACA9D214C5 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr 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 S1728161AbeIZUL4 (ORCPT ); Wed, 26 Sep 2018 16:11:56 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:40472 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726937AbeIZUL4 (ORCPT ); Wed, 26 Sep 2018 16:11:56 -0400 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 42L00S6PV6z9ttfr; Wed, 26 Sep 2018 15:58:48 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id XzXnEebpN7Lz; Wed, 26 Sep 2018 15:58:48 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 42L00S5kY8z9ttfn; Wed, 26 Sep 2018 15:58:48 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 525B78B817; Wed, 26 Sep 2018 15:58:49 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id uIZE3cJYrG0Z; Wed, 26 Sep 2018 15:58:49 +0200 (CEST) Received: from PO15451 (unknown [172.25.231.3]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 2C3E98B803; Wed, 26 Sep 2018 15:58:49 +0200 (CEST) Subject: Re: [PATCH] powerpc: Move a dereference below a NULL test To: zhong jiang , paulus@samba.org, benh@kernel.crashing.org, mpe@ellerman.id.au Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <1537962368-14019-1-git-send-email-zhongjiang@huawei.com> From: Christophe LEROY Message-ID: Date: Wed, 26 Sep 2018 15:58:48 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1537962368-14019-1-git-send-email-zhongjiang@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 26/09/2018 à 13:46, zhong jiang a écrit : > It is safe to move dereference below a NULL test. > > Signed-off-by: zhong jiang > --- > arch/powerpc/kernel/cacheinfo.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/kernel/cacheinfo.c b/arch/powerpc/kernel/cacheinfo.c > index a8f20e5..7f19714 100644 > --- a/arch/powerpc/kernel/cacheinfo.c > +++ b/arch/powerpc/kernel/cacheinfo.c > @@ -401,14 +401,13 @@ static struct cache *cache_lookup_or_instantiate(struct device_node *node, > struct cache *cache; > > cache = cache_lookup_by_node(node); > + if (!cache) > + cache = cache_do_one_devnode(node, level); But by doing this, you change the meaning of the following warning. Is that what you want ? In that case the text of the WARN_ONCE() should be changed, because the mismatch is not only on lookup now. Christophe > > WARN_ONCE(cache && cache->level != level, > "cache level mismatch on lookup (got %d, expected %d)\n", > cache->level, level); > > - if (!cache) > - cache = cache_do_one_devnode(node, level); > - > return cache; > } > >