From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+w=401wt.eu-S1763018AbXGLTdn@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1763018AbXGLTdn (ORCPT <rfc822;w@1wt.eu>);
	Thu, 12 Jul 2007 15:33:43 -0400
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756140AbXGLTdg
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Thu, 12 Jul 2007 15:33:36 -0400
Received: from smtp2.linux-foundation.org ([207.189.120.14]:52053 "EHLO
	smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK)
	by vger.kernel.org with ESMTP id S1752769AbXGLTde (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Thu, 12 Jul 2007 15:33:34 -0400
Date: Thu, 12 Jul 2007 12:31:36 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Alistair John Strachan <alistair@devzero.co.uk>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>,
       Andy Whitcroft <apw@shadowen.org>, Ralf Baechle <ralf@linux-mips.org>,
       Mark Mason <mason@broadcom.com>, Randy Dunlap <rdunlap@xenotime.net>,
       Joel Schopp <jschopp@austin.ibm.com>, linux-mips@linux-mips.org,
       linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sb1250-duart.c: SB1250 DUART serial support
Message-Id: <20070712123136.8e0b8eda.akpm@linux-foundation.org>
In-Reply-To: <200707122015.12078.alistair@devzero.co.uk>
References: <Pine.LNX.4.64N.0707121745010.3029@blysk.ds.pg.gda.pl>
	<469669F5.6070906@shadowen.org>
	<Pine.LNX.4.64N.0707121904211.3029@blysk.ds.pg.gda.pl>
	<200707122015.12078.alistair@devzero.co.uk>
X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, 12 Jul 2007 20:15:11 +0100
Alistair John Strachan <alistair@devzero.co.uk> wrote:

> On Thursday 12 July 2007 19:16:20 Maciej W. Rozycki wrote:
> > On Thu, 12 Jul 2007, Andy Whitcroft wrote:
> [snip]
> > > WARNING: declaring multiple variables together should be avoided
> > > #372: FILE: drivers/serial/sb1250-duart.c:246:
> > > +	unsigned int mctrl, status;
> >
> >  Well, this is probably superfluous -- why would anyone prefer:
> >
> > 	int r0;
> > 	int r1;
> > 	int r2;
> > 	int r3;
> > 	int r4;
> >
> > to:
> >
> > 	int r0, r1, r2, r3, r4;
> >
> > unconditionally?
> 
> Imagine you're working on a piece of kernel code that has a lot of parallel 
> churn. Conflicts on lines like "int a,b,c,d;" are more likely to cause Andrew 
> et al pain, which I guess is the rationale for discouraging it. Conversely, 
> if the variables are kept separate, diff handles it fine.

That, plus the first style leaves room for useful code comments.  The lack
of which is often a maintainability bug.