From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753129AbaEHHMy (ORCPT ); Thu, 8 May 2014 03:12:54 -0400 Received: from cpsmtpb-ews06.kpnxchange.com ([213.75.39.9]:49199 "EHLO cpsmtpb-ews06.kpnxchange.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751516AbaEHHMx (ORCPT ); Thu, 8 May 2014 03:12:53 -0400 Message-ID: <1399533171.19191.8.camel@x41> Subject: Re: [PATCH v2] NVMe: silence GCC warning on 32 bit From: Paul Bolle To: Matthew Wilcox Cc: Keith Busch , Geert Uytterhoeven , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org Date: Thu, 08 May 2014 09:12:51 +0200 In-Reply-To: <1395675399.6440.14.camel@x220> References: <1392714172-2712-1-git-send-email-geert@linux-m68k.org> <1392934261.15264.22.camel@x220> <1393925767.3038.23.camel@x220> <20140324131104.GC5777@linux.intel.com> <20140324133154.GD5777@linux.intel.com> <1395675399.6440.14.camel@x220> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-2.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 08 May 2014 07:12:51.0831 (UTC) FILETIME=[ECD3E870:01CF6A8C] X-RcptDomain: vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Matthew, Paul Bolle schreef op ma 24-03-2014 om 16:36 [+0100]: > On Mon, 2014-03-24 at 09:31 -0400, Matthew Wilcox wrote: > > I should try things myself before opening my big mouth. Weird. Using > > gcc-4.8, I see the same thing. Guess I should just apply the patch, > > though it feels wrong to be initialising an entire struct just to silence > > a bogus compiler warning :-( > > I noticed this difference on a 32 bit x86 machine and a 64 bit x86 > machine that are both running Fedora 20. They both should be at > gcc-4.8.2 for quite some time now (if I grepped the yum log correctly). > > Anyhow, the warning on 32 bit is rather noisy, so I wanted it gone. But > my comments should make clear I'm not really happy with this patch. > > And as this is now unlikely to be in time for v3.14, we might decide to > dig deeper. It won't be the first time that a rather small change (say, > converting a variable from signed to unsigned) turns out be enough to > make GCC understand the flow of the code. This noisy warning is still seen when compiling v3.15-rc4 for x86 (32 bit, that is). Assuming this patch is not queued anywhere: is the unsophisticated approach of my v2 acceptable or would you like me to try and find the cause of this warning? Paul Bolle