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=-15.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,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 D0888C433DB for ; Fri, 5 Feb 2021 07:22:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7CD0364F70 for ; Fri, 5 Feb 2021 07:22:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231445AbhBEHV6 (ORCPT ); Fri, 5 Feb 2021 02:21:58 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:43408 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230489AbhBEHVv (ORCPT ); Fri, 5 Feb 2021 02:21:51 -0500 Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4DX6KF4L2tz9tyrq; Fri, 5 Feb 2021 08:21:05 +0100 (CET) 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 nOfXsRkH2akN; Fri, 5 Feb 2021 08:21:05 +0100 (CET) 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 4DX6KF3V8tz9tyrZ; Fri, 5 Feb 2021 08:21:05 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 637988B75F; Fri, 5 Feb 2021 08:21:06 +0100 (CET) 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 7RRufg4Z5zAI; Fri, 5 Feb 2021 08:21:06 +0100 (CET) Received: from [192.168.4.90] (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id D41418B81B; Fri, 5 Feb 2021 08:21:05 +0100 (CET) Subject: Re: [PATCH] arch:powerpc simple_write_to_buffer return check To: Mayank Suman , ruscur@russell.cc, oohall@gmail.com, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org References: From: Christophe Leroy Message-ID: <8be2b91b-cef1-ea68-836a-94c8a574d760@csgroup.eu> Date: Fri, 5 Feb 2021 08:21:04 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Please provide some description of the change. And please clarify the patch subject, because as far as I can see, the return is already checked allthough the check seams wrong. Le 04/02/2021 à 19:16, Mayank Suman a écrit : > Signed-off-by: Mayank Suman > --- > arch/powerpc/kernel/eeh.c | 8 ++++---- > arch/powerpc/platforms/powernv/eeh-powernv.c | 4 ++-- > 2 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/eeh.c b/arch/powerpc/kernel/eeh.c > index 813713c9120c..2dbe1558a71f 100644 > --- a/arch/powerpc/kernel/eeh.c > +++ b/arch/powerpc/kernel/eeh.c > @@ -1628,8 +1628,8 @@ static ssize_t eeh_force_recover_write(struct file *filp, > char buf[20]; > int ret; > > - ret = simple_write_to_buffer(buf, sizeof(buf), ppos, user_buf, count); > - if (!ret) > + ret = simple_write_to_buffer(buf, sizeof(buf)-1, ppos, user_buf, count); > + if (ret <= 0) > return -EFAULT; Why return -EFAULT when the function has returned -EINVAL ? And why is it -EFAULT when ret is 0 ? EFAULT means error accessing memory. > > /* > @@ -1696,7 +1696,7 @@ static ssize_t eeh_dev_check_write(struct file *filp, > > memset(buf, 0, sizeof(buf)); > ret = simple_write_to_buffer(buf, sizeof(buf)-1, ppos, user_buf, count); > - if (!ret) > + if (ret <= 0) > return -EFAULT; > > ret = sscanf(buf, "%x:%x:%x.%x", &domain, &bus, &dev, &fn); > @@ -1836,7 +1836,7 @@ static ssize_t eeh_dev_break_write(struct file *filp, > > memset(buf, 0, sizeof(buf)); > ret = simple_write_to_buffer(buf, sizeof(buf)-1, ppos, user_buf, count); > - if (!ret) > + if (ret <= 0) > return -EFAULT; > > ret = sscanf(buf, "%x:%x:%x.%x", &domain, &bus, &dev, &fn); > diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c > index 89e22c460ebf..36ed2b8f7375 100644 > --- a/arch/powerpc/platforms/powernv/eeh-powernv.c > +++ b/arch/powerpc/platforms/powernv/eeh-powernv.c > @@ -76,8 +76,8 @@ static ssize_t pnv_eeh_ei_write(struct file *filp, > return -ENXIO; > > /* Copy over argument buffer */ > - ret = simple_write_to_buffer(buf, sizeof(buf), ppos, user_buf, count); > - if (!ret) > + ret = simple_write_to_buffer(buf, sizeof(buf)-1, ppos, user_buf, count); > + if (ret <= 0) > return -EFAULT; > > /* Retrieve parameters */ >