Re: [PATCH] SLQB: Use _RET_IP_ instead of__builtin_return_address(0)

From: Robert P. J. Day
Date: Sun May 03 2009 - 08:21:06 EST


On Sun, 3 May 2009, Pekka J Enberg wrote:

> From: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
>
> This patch changes SLQB to use the shorter _RET_IP_ form for consistency
> with SLUB and to prepare SQLB for eventual kmemtrace hooks.

... big snip ...

> void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
> {
> - return __kmem_cache_alloc(s, gfpflags, __builtin_return_address(0));
> + return __kmem_cache_alloc(s, gfpflags, _RET_IP_);
> }

since i originally pointed out this possible simplification, i might
as well also point out that the above is not necessarily correct. in
include/linux/kernel.h:

#define _RET_IP_ (unsigned long)__builtin_return_address(0)

as in, _RET_IP_ represents the **(unsigned long)** cast of that
(void*) value. so, technically, that's not merely an aesthetic
replacement. is that still what you wanted?

rday
--

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Robert P. J. Day Waterloo, Ontario, CANADA

Linux Consulting, Training and Annoying Kernel Pedantry.

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