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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>,
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Subject: Re: [PATCH] sb1250-duart.c: SB1250 DUART serial support
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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.