linux-kernel - Re: make checkpatch warn about memset with swapped arguments.

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Date:	Thu, 17 Mar 2011 14:57:30 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Dave Jones <davej@...hat.com>
Cc:	Steven Rostedt <rostedt@...dmis.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: make checkpatch warn about memset with swapped arguments.

On Thu, 17 Mar 2011 17:32:52 -0400
Dave Jones <davej@...hat.com> wrote:

> On Thu, Mar 17, 2011 at 02:11:08PM -0700, Andrew Morton wrote:
>  
>  > Dave's patch is tested (I assume), so it wins ;)
> 
> indeed, it's the one I've been using for.. ages.
> 
>  > Maybe it's just me, but I think it would be better to use bzero() for
>  > this operation - it's more readable and it can't be screwed up.  Then
>  > checkpatch checks for memset(xxx, 0, xxx) and for memset(xxx, xxx, 0)
>  > and says "hey, use bzero".  
> 
> god yes.  I don't know why it fell out of favor in userspace[*], but we
> don't have to follow suit in the kernel.  I thought we actually had
> a generic bzero, but it seems not from a quick grep.  I'll hack something up.
> 
> it only needs to be a #define bzero(x,y)	memset (x, 0, y);
> 
> where should it live, linux/kernel.h ?

Thou shalt not implement in CPP that which can be implemented in C.

and..

Thou shalt not implement in C that which is already a gcc builtin :)

I'm OK with switching from memset to bzero as the preferred way of
clearing memory (shorter, clearer, not susceptible to the arg reversal
bug).  Is Linus?

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