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Message-ID: <20100105224901.GB32584@Krystal>
Date: Tue, 5 Jan 2010 17:49:01 -0500
From: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
To: Christoph Lameter <cl@...ux-foundation.org>
Cc: Tejun Heo <tj@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [RFC local_t removal V1 1/4] Add add_local() and
add_local_return()
* Christoph Lameter (cl@...ux-foundation.org) wrote:
> We already have cmpxchg_local that can work on an arbitrary type. The cmpxchg
> is only safe from concurrent access on the local cpu.
>
> Add another operation that in the similar fasion allow "local" safe adds to
> a variable.
>
> Signed-off-by: Christoph Lameter <cl@...ux-foundation.org>
>
> ---
> arch/alpha/include/asm/add-local.h | 2 +
> arch/arm/include/asm/add-local.h | 2 +
> arch/avr32/include/asm/add-local.h | 2 +
> arch/blackfin/include/asm/add-local.h | 2 +
> arch/cris/include/asm/add-local.h | 2 +
> arch/frv/include/asm/add-local.h | 2 +
> arch/h8300/include/asm/add-local.h | 2 +
> arch/ia64/include/asm/add-local.h | 2 +
> arch/m32r/include/asm/add-local.h | 2 +
> arch/m68k/include/asm/add-local.h | 2 +
> arch/microblaze/include/asm/add-local.h | 2 +
> arch/mips/include/asm/add-local.h | 2 +
> arch/mn10300/include/asm/add-local.h | 2 +
> arch/parisc/include/asm/add-local.h | 2 +
> arch/powerpc/include/asm/add-local.h | 2 +
> arch/s390/include/asm/add-local.h | 2 +
> arch/score/include/asm/add-local.h | 2 +
> arch/sh/include/asm/add-local.h | 2 +
> arch/sparc/include/asm/add-local.h | 2 +
> arch/um/include/asm/add-local.h | 2 +
> arch/x86/include/asm/add-local.h | 2 +
> arch/xtensa/include/asm/add-local.h | 2 +
> include/asm-generic/add-local-generic.h | 40 ++++++++++++++++++++++++++++++++
> include/asm-generic/add-local.h | 13 ++++++++++
> 24 files changed, 97 insertions(+)
The problem I see here is that with ~5-6 operations, we will end up
having 20*5 = 100 headers only for this. Can we combine these in a
single header file instead ? local.h wasn't bad in this respect.
Also, separating all these in sub-files will make it a bit difficult to
pinpoint errors that would arise from using a bad combination of, e.g.
generic add with a non-protected read or set.
Thanks,
Mathieu
>
> Index: linux-2.6/include/asm-generic/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/include/asm-generic/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,13 @@
> +#ifndef __ASM_GENERIC_ADD_LOCAL_H
> +#define __ASM_GENERIC_ADD_LOCAL_H
> +
> +#include <asm-generic/add-local-generic.h>
> +
> +#define add_return_local(ptr, v) \
> + ((__typeof__(*(ptr)))__add_return_local_generic((ptr), \
> + (unsigned long)(v), sizeof(*(ptr))))
> +
> +#define add_local(ptr, v) (void)__add_return_local_generic((ptr), \
> + (unsigned long)(v), sizeof(*(ptr)))
> +
> +#endif
> Index: linux-2.6/arch/alpha/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/alpha/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/arm/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/arm/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/avr32/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/avr32/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/blackfin/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/blackfin/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/cris/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/cris/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/frv/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/frv/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/h8300/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/h8300/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/ia64/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/ia64/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/m32r/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/m32r/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/m68k/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/m68k/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/microblaze/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/microblaze/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/mips/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/mips/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/mn10300/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/mn10300/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/parisc/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/parisc/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/powerpc/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/powerpc/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/s390/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/s390/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/score/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/score/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/sh/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/sh/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/sparc/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/sparc/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/um/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/um/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/x86/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/x86/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/arch/xtensa/include/asm/add-local.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/arch/xtensa/include/asm/add-local.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,2 @@
> +#include <asm-generic/add-local.h>
> +
> Index: linux-2.6/include/asm-generic/add-local-generic.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6/include/asm-generic/add-local-generic.h 2010-01-05 15:36:02.000000000 -0600
> @@ -0,0 +1,40 @@
> +#ifndef __ASM_GENERIC_ADD_LOCAL_GENERIC_H
> +#define __ASM_GENERIC_ADD_LOCAL_GENERIC_H
> +
> +#include <linux/types.h>
> +
> +extern unsigned long wrong_size_add_local(volatile void *ptr);
> +
> +/*
> + * Generic version of __add_return_local (disables interrupts). Takes an
> + * unsigned long parameter, supporting various types of architectures.
> + */
> +static inline unsigned long __add_return_local_generic(volatile void *ptr,
> + unsigned long value, int size)
> +{
> + unsigned long flags, r;
> +
> + /*
> + * Sanity checking, compile-time.
> + */
> + if (size == 8 && sizeof(unsigned long) != 8)
> + wrong_size_add_local(ptr);
> +
> + local_irq_save(flags);
> + switch (size) {
> + case 1: r = (*((u8 *)ptr) += value);
> + break;
> + case 2: r = (*((u16 *)ptr) += value);
> + break;
> + case 4: r = (*((u32 *)ptr) += value);
> + break;
> + case 8: r = (*((u64 *)ptr) += value);
> + break;
> + default:
> + wrong_size_add_local(ptr);
> + }
> + local_irq_restore(flags);
> + return r;
> +}
> +
> +#endif
>
> --
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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