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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E7B67C433E0 for ; Fri, 22 May 2020 17:22:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BF4C3206C3 for ; Fri, 22 May 2020 17:22:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730720AbgEVRWJ (ORCPT ); Fri, 22 May 2020 13:22:09 -0400 Received: from smtprelay0183.hostedemail.com ([216.40.44.183]:59076 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730471AbgEVRWI (ORCPT ); Fri, 22 May 2020 13:22:08 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay04.hostedemail.com (Postfix) with ESMTP id 452C2180A8153; Fri, 22 May 2020 17:22:07 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: wall47_0510ab926d28 X-Filterd-Recvd-Size: 3359 Received: from XPS-9350.home (unknown [47.151.136.130]) (Authenticated sender: joe@perches.com) by omf12.hostedemail.com (Postfix) with ESMTPA; Fri, 22 May 2020 17:22:05 +0000 (UTC) Message-ID: <162676bb69044efadd31daa9ea49fc6fb9664297.camel@perches.com> Subject: Re: [PATCH] taging: speakup: remove volatile From: Joe Perches To: Samuel Thibault Cc: Dan Carpenter , MugilRaj , devel@driverdev.osuosl.org, Kirk Reiser , Greg Kroah-Hartman , speakup@linux-speakup.org, linux-kernel@vger.kernel.org, Chris Brannon Date: Fri, 22 May 2020 10:22:03 -0700 In-Reply-To: <20200522171312.s2ciifuxozwav2ym@function> References: <1590138989-6091-1-git-send-email-dmugil2000@gmail.com> <20200522103406.GK30374@kadam> <6ab4139ec78928961a19e5fdbda139bb8cff9cb5.camel@perches.com> <20200522171312.s2ciifuxozwav2ym@function> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.36.2-0ubuntu1 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 Fri, 2020-05-22 at 19:13 +0200, Samuel Thibault wrote: > Joe Perches, le ven. 22 mai 2020 09:36:05 -0700, a ecrit: > > On Fri, 2020-05-22 at 13:34 +0300, Dan Carpenter wrote: > > > On Fri, May 22, 2020 at 02:46:28PM +0530, MugilRaj wrote: > > > > fix checkpatch.pl warning, which is Use of volatile is usually wrong: see > > > > Documentation/process/volatile-considered-harmful.rst > > > > Signed-off-by: MugilRaj > > > > > > Please put a blank before the Signed-off-by line. > > > > > > Probably there should be a space between your first and last name. It's > > > supposed to your legal name like for signing a legal document so use > > > whatever is appropriate legal documents in your country. > > > > > > Also the Documentation/process/volatile-considered-harmful.rst explains > > > that people often use "volatile" when they should be using locking for > > > synchronization. That seems to be the case here. So the correct fix is > > > to add locking. That's a little bit complicated to do and requires > > > testing. > > > > > > If we apply this patch, then we have silenced the warning so now someone > > > will have to look for the bug. But if we leave it as-is, then everyone > > > will know that the code is buggy. So let's leave it as-is until we are > > > able to fix the bug. > > > > > > It's always better to have easy to find bugs, than hidden bugs. > > > > And better still to comment known opportunities to > > improve the code so the next time someone tries to > > remove this volatile, there's a comment right there > > showing what's necessary instead. > > Actually I don't think adding the suggestion is a good thing if it's > only a "rule-of-thumb-replace-volatile-with-lock". > > Actually possibly volatile might not even be needed because there could > be already a lock protecting this. > > Put another way: I don't think putting any hint here would help, on the > contrary, somebody has to really look at what protection is needed, > without getting influenced by rules-of-thumb. checkpatch newbies/robots will submit this change again otherwise. Comment wording can always be improved.