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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNWANTED_LANGUAGE_BODY autolearn=no 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 919DDC76186 for ; Tue, 30 Jul 2019 00:16:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6861A20679 for ; Tue, 30 Jul 2019 00:16:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729182AbfG3AQk (ORCPT ); Mon, 29 Jul 2019 20:16:40 -0400 Received: from smtprelay0237.hostedemail.com ([216.40.44.237]:51011 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728195AbfG3AQk (ORCPT ); Mon, 29 Jul 2019 20:16:40 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay01.hostedemail.com (Postfix) with ESMTP id 25656100E86C2; Tue, 30 Jul 2019 00:16:39 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: duck20_742442808ff0f X-Filterd-Recvd-Size: 2479 Received: from XPS-9350 (cpe-23-242-196-136.socal.res.rr.com [23.242.196.136]) (Authenticated sender: joe@perches.com) by omf06.hostedemail.com (Postfix) with ESMTPA; Tue, 30 Jul 2019 00:16:37 +0000 (UTC) Message-ID: <5dee05d6cb8498b3e636f5e8a62da673334cb5a9.camel@perches.com> Subject: Re: [PATCH 08/12] printk: Replace strncmp with str_has_prefix From: Joe Perches To: Chuhong Yuan Cc: Petr Mladek , Sergey Senozhatsky , Steven Rostedt , linux-kernel@vger.kernel.org Date: Mon, 29 Jul 2019 17:16:35 -0700 In-Reply-To: <20190729151505.9660-1-hslester96@gmail.com> References: <20190729151505.9660-1-hslester96@gmail.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.30.5-0ubuntu0.18.10.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2019-07-29 at 23:15 +0800, Chuhong Yuan wrote: > strncmp(str, const, len) is error-prone. > We had better use newly introduced > str_has_prefix() instead of it. [] > diff --git a/kernel/printk/braille.c b/kernel/printk/braille.c [] > @@ -11,10 +11,10 @@ > > int _braille_console_setup(char **str, char **brl_options) > { > - if (!strncmp(*str, "brl,", 4)) { > + if (str_has_prefix(*str, "brl,")) { > *brl_options = ""; > *str += 4; > - } else if (!strncmp(*str, "brl=", 4)) { > + } else if (str_has_prefix(*str, "brl=")) { > *brl_options = *str + 4; Better to get rid of the += 4 uses too by storing the result of str_has_prefix and using that as the addend. Perhaps size_t len; if ((len = str_has_prefix(*str, "brl,"))) { *brl_options = ""; *str += len; } else if ((len = str_has_prefix(*str, "brl="))) { etc... > *str = strchr(*brl_options, ','); > if (!*str) { > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c [] > @@ -121,13 +121,13 @@ static int __control_devkmsg(char *str) > if (!str) > return -EINVAL; > > - if (!strncmp(str, "on", 2)) { > + if (str_has_prefix(str, "on")) { > devkmsg_log = DEVKMSG_LOG_MASK_ON; > return 2; > - } else if (!strncmp(str, "off", 3)) { > + } else if (str_has_prefix(str, "off")) { > devkmsg_log = DEVKMSG_LOG_MASK_OFF; > return 3; > - } else if (!strncmp(str, "ratelimit", 9)) { > + } else if (str_has_prefix(str, "ratelimit")) { > devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT; > return 9; > } here too.