From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758563AbYF0HTT (ORCPT ); Fri, 27 Jun 2008 03:19:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754379AbYF0HTE (ORCPT ); Fri, 27 Jun 2008 03:19:04 -0400 Received: from gw-colo-pa.panasas.com ([66.238.117.130]:32752 "EHLO natasha.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754414AbYF0HTD (ORCPT ); Fri, 27 Jun 2008 03:19:03 -0400 Message-ID: <4864944B.5020601@panasas.com> Date: Fri, 27 Jun 2008 10:18:35 +0300 From: Benny Halevy User-Agent: Thunderbird 2.0.0.12 (X11/20080213) MIME-Version: 1.0 To: Greg KH CC: Alan Cox , lkml Subject: Re: keyspan_pda.c use of keyspan_pda_get_modem_info References: <4863AD33.3070005@panasas.com> <20080626162346.5c324701@lxorguk.ukuu.org.uk> <20080627041735.GB8145@kroah.com> In-Reply-To: <20080627041735.GB8145@kroah.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 27 Jun 2008 07:18:37.0124 (UTC) FILETIME=[0438B040:01C8D826] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Jun. 27, 2008, 7:17 +0300, Greg KH wrote: > On Thu, Jun 26, 2008 at 04:23:46PM +0100, Alan Cox wrote: >>> In these two call sites the callers bail out if >>> keyspan_pda_get_modem_info return value is < 0 >> I don't think that is what the compiler is warning about. >> >> We error on rc < 0 >> We use the returned status on rc >= 0 >> >> We set the returned status on rc > 0 >> >> So the rc = 0 case is broken and gcc seems to be correct about that > > Yes, that is correct, fortunatly that function can never return rc = 0, > so this will not happen in real life. > > But there is really no way the compiler can ever figure that out, so I > don't blame it for complaining. > > If you want to make a simple patch to make the compiler happy and be > quiet about the warning, I'll take it. Cool. I'll send a patch initializing status to 0. Now, what about the rc == 0 case? Does it warrant a BUG_ON() if it should ever happen? Benny > > thanks, > > greg k-h