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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51BC3CD13CF for ; Sun, 17 Sep 2023 09:49:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236042AbjIQJtX (ORCPT ); Sun, 17 Sep 2023 05:49:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236387AbjIQJtA (ORCPT ); Sun, 17 Sep 2023 05:49:00 -0400 Received: from 1wt.eu (ded1.1wt.eu [163.172.96.212]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7E6E7193; Sun, 17 Sep 2023 02:48:49 -0700 (PDT) Received: (from willy@localhost) by pcw.home.local (8.15.2/8.15.2/Submit) id 38H9mRSk011095; Sun, 17 Sep 2023 11:48:27 +0200 Date: Sun, 17 Sep 2023 11:48:27 +0200 From: Willy Tarreau To: Thomas =?iso-8859-1?Q?Wei=DFschuh?= Cc: Paul Walmsley , Palmer Dabbelt , Albert Ou , Shuah Khan , linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH 2/4] tools/nolibc: avoid unused parameter warnings for ENOSYS fallbacks Message-ID: <20230917094827.GA11081@1wt.eu> References: <20230914-nolibc-syscall-nr-v1-0-e50df410da11@weissschuh.net> <20230914-nolibc-syscall-nr-v1-2-e50df410da11@weissschuh.net> <20230917025851.GE9646@1wt.eu> <2bd688b7-5f1b-44ca-a41b-6e90dc3e8557@t-8ch.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2bd688b7-5f1b-44ca-a41b-6e90dc3e8557@t-8ch.de> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Sep 17, 2023 at 07:49:57AM +0200, Thomas Weißschuh wrote: > On 2023-09-17 04:58:51+0200, Willy Tarreau wrote: > > On Thu, Sep 14, 2023 at 06:01:18PM +0200, Thomas Weißschuh wrote: > > > The ENOSYS fallback code does not use its functions parameters. > > > This can lead to compiler warnings about unused parameters. > > > > > > Explicitly avoid these warnings. > > > > Just out of curiosity, did you find a valid case for enabling this > > warning or were you trying various combinations ? I'm asking because > > I've never seen it enabled anywhere given that it's probably the most > > useless and unusable warning: as soon as you're dealing with function > > pointers, you start to have multiple functions with a similar > > prototype, some of which just don't need certain arguments, and the > > only way to shut the warning is to significantly uglify the code. > > nolibc-test uses it currently and I also used it in some projects. OK then let's handle it. > > @@ -934,6 +960,11 @@ int sys_select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds, struct timeva > > #endif > > return my_syscall5(__NR__newselect, nfds, rfds, wfds, efds, timeout); > > #else > > + return no_syscall5(nfds, rfds, wfds, efds, timeout); > > - return -ENOSYS; > > #endif > > > > What do you think ? > > The idea sounds good. But "no_syscall5" sounds a bit non-obvious to me. Of course, I was just trying to illustrate. I'm never good at giving names. > Maybe the macro-equivalent of this? > > static inline int __nolibc_enosys(...) > { > return -ENOSYS; > } > > The only-vararg function unfortunately needs C23 so we can't use it. > > It's clear to the users that this is about ENOSYS and we don't need a > bunch of new macros similar. I like it, I didn't think about varargs, it's an excellent idea! Let's just do simpler, start with a first arg "syscall_num" that we may later reuse for debugging, and just mark this one unused: static inline int __nolibc_enosys(int syscall_num, ...) { (void)syscall_num; return -ENOSYS; } Willy