From: Christoph Hellwig <hch@infradead.org>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] Use more gcc extensions in the Linux headers
Date: Fri, 9 Mar 2007 07:52:45 +0000 [thread overview]
Message-ID: <20070309075245.GD8798@infradead.org> (raw)
In-Reply-To: <1173419792.32234.131.camel@localhost.localdomain>
On Fri, Mar 09, 2007 at 04:56:32PM +1100, Rusty Russell wrote:
> __builtin_types_compatible_p() has been around since gcc 2.95, and we
> don't use it anywhere. This patch quietly fixes that.
>
> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
>
> diff -r f0ff8138f993 include/linux/kernel.h
> --- a/include/linux/kernel.h Fri Mar 09 16:40:25 2007 +1100
> +++ b/include/linux/kernel.h Fri Mar 09 16:44:04 2007 +1100
> @@ -35,7 +35,9 @@ extern const char linux_proc_banner[];
> #define ALIGN(x,a) __ALIGN_MASK(x,(typeof(x))(a)-1)
> #define __ALIGN_MASK(x,mask) (((x)+(mask))&~(mask))
>
> -#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
> +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) \
> + + sizeof(typeof(int[1 - 2*!!__builtin_types_compatible_p(typeof(arr), \
> + typeof(&arr[0]))]))*0)
This needs a comment explaning why we're doing this, and maybe a little
explanation of the combination of gcc magic and C trickery used to implement
it to the brave non-uberhacker people trying to understand linux headers.
next prev parent reply other threads:[~2007-03-09 7:52 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-09 5:56 [PATCH] Use more gcc extensions in the Linux headers Rusty Russell
2007-03-09 6:22 ` Stephen Rothwell
2007-03-09 6:35 ` Linus Torvalds
2007-03-09 6:50 ` Andrey Panin
2007-03-09 7:53 ` Christoph Hellwig
2007-03-09 9:02 ` Andrey Panin
2007-03-09 9:05 ` Christoph Hellwig
2007-03-09 17:47 ` Linus Torvalds
2007-03-10 20:36 ` Trent Piepho
2007-03-09 7:52 ` Christoph Hellwig [this message]
2007-03-09 8:35 ` Jarek Poplawski
2007-03-09 11:27 ` Theodore Ts'o
2007-03-09 16:52 ` Andi Kleen
2007-03-09 22:57 ` Rusty Russell
2007-03-09 23:02 ` Randy Dunlap
2007-03-09 23:09 ` Robert P. J. Day
2007-03-09 23:12 ` Roland Dreier
2007-03-10 1:04 ` Jan Engelhardt
2007-03-11 2:50 ` Rusty Russell
2007-03-11 2:58 ` Jan Engelhardt
2007-03-11 3:19 ` Rusty Russell
2007-03-11 21:40 ` Valdis.Kletnieks
2007-03-10 4:03 ` Valdis.Kletnieks
2007-03-10 4:24 ` Randy Dunlap
2007-03-11 15:56 ` Valdis.Kletnieks
2007-03-10 5:19 ` Nigel Cunningham
2007-03-10 14:01 ` Jan Engelhardt
2007-03-10 15:18 ` Andreas Schwab
2007-03-10 16:53 ` Jan Engelhardt
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