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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 48CA3C47404 for ; Wed, 9 Oct 2019 14:30:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1C236206BB for ; Wed, 9 Oct 2019 14:30:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="OOvnWUKC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731514AbfJIOay (ORCPT ); Wed, 9 Oct 2019 10:30:54 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:34858 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729865AbfJIOax (ORCPT ); Wed, 9 Oct 2019 10:30:53 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x99ET5EP091425; Wed, 9 Oct 2019 14:30:16 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2019-08-05; bh=xieOlnCZNdH9rUJsmmz2r6xC3pikyG8vEfffwj7nqrw=; b=OOvnWUKCQhvigjaczx/qR1uBte5t61Z/QDolYiL05qZxUCsWNHdRQKhJWREdJEd50eVy S5jenrGsYWmitNcsX/IDCRwufe6OiXJ5UQ5M2ppSpZWaa+AcSSoJTDT7DWzaNvZ92hVO uMGSXQCEW/N2FRRMCg0SbTziGa6IWx3O+KfE46GFbifC9CUGDfZt+0c7VUvcHx2pt6Gs NE04+Y6luipnF1BAt8CfIXyGgYtIyvqAw9xs4V9B/QLW/mdy86Nk8Lju35NBFPsrTu+E kiSOurdkp2EDfP9qCSs9784af8DYrJeekHVKz5Tay4qF9HKcwM/8yngIl6RdKmbPI7a4 Nw== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2120.oracle.com with ESMTP id 2vektrmsct-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 09 Oct 2019 14:30:15 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x99ENELC032173; Wed, 9 Oct 2019 14:30:15 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userp3030.oracle.com with ESMTP id 2vgev1gx1s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 09 Oct 2019 14:30:15 +0000 Received: from abhmp0003.oracle.com (abhmp0003.oracle.com [141.146.116.9]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x99EUAlf020123; Wed, 9 Oct 2019 14:30:12 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 09 Oct 2019 07:30:10 -0700 Date: Wed, 9 Oct 2019 17:30:01 +0300 From: Dan Carpenter To: Rasmus Villemoes Cc: Markus Elfring , kernel-janitors@vger.kernel.org, Alexander Shishkin , Andrew Morton , Andy Shevchenko , Joe Perches , Kees Cook , Nick Desaulniers , Steven Rostedt , LKML Subject: Re: [PATCH] string.h: Mark 34 functions with __must_check Message-ID: <20191009143000.GD13286@kadam> References: <75f70e5e-9ece-d6d1-a2c5-2f3ad79b9ccb@web.de> <954c5d70-742f-7b0e-57ad-ea967e93be89@rasmusvillemoes.dk> <20191009135522.GA20194@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9404 signatures=668684 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=814 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910090139 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9404 signatures=668684 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=894 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1910090140 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 09, 2019 at 04:21:20PM +0200, Rasmus Villemoes wrote: > On 09/10/2019 15.56, Dan Carpenter wrote: > > That's because glibc strlen is annotated with __attribute_pure__ which > > means it has no side effects. > > I know, except it has nothing to do with glibc headers. Just try the > same thing in the kernel. gcc itself knows this about __builtin_strlen() > etc. If anything, we could annotate some of our non-standard functions > (say, memchr_inv) with __pure - then we'd both get the Wunused-value in > the nonsense cases, and allow gcc to optimize or reorder the calls. Huh. You're right. GCC already knows. So this patch is pointless like you say. regards, dan carpenter