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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 80CD5C433FF for ; Wed, 31 Jul 2019 13:16:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E21E208C3 for ; Wed, 31 Jul 2019 13:16:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729346AbfGaNP7 (ORCPT ); Wed, 31 Jul 2019 09:15:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:49072 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729136AbfGaNP6 (ORCPT ); Wed, 31 Jul 2019 09:15:58 -0400 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 713AB20693; Wed, 31 Jul 2019 13:15:57 +0000 (UTC) Date: Wed, 31 Jul 2019 09:15:55 -0400 From: Steven Rostedt To: Geert Uytterhoeven Cc: Petr Mladek , Sergey Senozhatsky , linux-kernel@vger.kernel.org Subject: Re: [PATCH] printk: Use strlen/sizeof instead of hardcoded constants Message-ID: <20190731091555.1d764ba1@gandalf.local.home> In-Reply-To: <20190731123922.14056-1-geert+renesas@glider.be> References: <20190731123922.14056-1-geert+renesas@glider.be> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 31 Jul 2019 14:39:22 +0200 Geert Uytterhoeven wrote: > Replace hardcoded string length or size constants by proper strlen() or > sizeof() constructs. As the strings are constant, gcc will reduce the > lengths or sizes to constants again. > > Signed-off-by: Geert Uytterhoeven > --- > Assembler output before/after compared: no change in generated code. > --- > include/linux/printk.h | 3 +-- > kernel/printk/printk.c | 12 ++++++------ > 2 files changed, 7 insertions(+), 8 deletions(-) > > diff --git a/include/linux/printk.h b/include/linux/printk.h > index cefd374c47b1f88e..9a85d2eb6ff63460 100644 > --- a/include/linux/printk.h > +++ b/include/linux/printk.h > @@ -77,8 +77,7 @@ static inline void console_verbose(void) > console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH; > } > > -/* strlen("ratelimit") + 1 */ > -#define DEVKMSG_STR_MAX_SIZE 10 > +#define DEVKMSG_STR_MAX_SIZE sizeof("ratelimit") > extern char devkmsg_log_str[]; > struct ctl_table; > > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c > index 1888f6a3b694cb88..e8f332f0ae3595e8 100644 > --- a/kernel/printk/printk.c > +++ b/kernel/printk/printk.c > @@ -121,15 +121,15 @@ static int __control_devkmsg(char *str) > if (!str) > return -EINVAL; > > - if (!strncmp(str, "on", 2)) { > + if (!strncmp(str, "on", strlen("on"))) { > devkmsg_log = DEVKMSG_LOG_MASK_ON; > - return 2; > - } else if (!strncmp(str, "off", 3)) { > + return strlen("on"); > + } else if (!strncmp(str, "off", strlen("off"))) { > devkmsg_log = DEVKMSG_LOG_MASK_OFF; > - return 3; > - } else if (!strncmp(str, "ratelimit", 9)) { > + return strlen("off"); > + } else if (!strncmp(str, "ratelimit", strlen("ratelimit"))) { Perhaps replacing all these with str_has_prefix() may be a better idea. -- Steve > devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT; > - return 9; > + return strlen("ratelimit"); > } > return -EINVAL; > }