linux-kernel - Re: memset as memzero

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Message-ID: <20070922093507.GB7226@cvg>
Date:	Sat, 22 Sep 2007 13:35:07 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	"Robert P. J. Day" <rpjday@...dspring.com>
Cc:	Cyrill Gorcunov <gorcunov@...il.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Ingo Molnar <mingo@...e.hu>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: memset as memzero

[Robert P. J. Day - Sat, Sep 22, 2007 at 04:48:28AM -0400]
| On Sat, 22 Sep 2007, Cyrill Gorcunov wrote:
| 
| > Hi list,
| >
| > could anyone tell me why there is no official memzero function (or
| > macros) in the kernel. As I see a lot of kernel parts calls for it
| > (defying own macros as alias to memset). Maybe there is a special
| > reason not to do so? Actually my suggestion is to define _one_
| > general macros for this.
| 
| i brought up this issue on the KJ list once upon a time:
| 
| https://lists.linux-foundation.org/pipermail/kernel-janitors/2007-February/017847.html
| 
| and there didn't seem to be much enthusiasm for it.
| 
|   however, i am still curious why there isn't more use of the
| already-defined "clear_page" macro.  most architectures appear to
| define it:
| 
| $ grep -r "define.*clear_page" include
| 
| but there are still numerous explicit calls to memset() to zero a
| chunk of memory that is exactly PAGE_SIZE in size.  just an
| observation.
| 
| rday
| -- 
| ========================================================================
| Robert P. J. Day
| Linux Consulting, Training and Annoying Kernel Pedantry
| Waterloo, Ontario, CANADA
| 
| http://crashcourse.ca
| ========================================================================
| 

Thanks Robert for the answer, I'll mark this (clear_page) in my "must to
take a look" list ;)
Well if there is no strong reason of keeping this separate '#define memzero'
I think it's a good case to merge them in some _single_ #define ;)

Waiting for other comments...

P.S.
In a mail you pointed to said that memset(...,0,...) is quite clear -
yes it's quite clear indeed but we already _have_ a lot of '#define memzero'
and who knows or may give the guarantee that new '#define memzero '_will not_'
appear in the kernel.

		Cyrill

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