forked from luck/tmp_suning_uos_patched
febdbfe8a9
Since the smp_mb__{before,after}*() ops are fundamentally dependent on
how an arch can implement atomics it doesn't make sense to have 3
variants of them. They must all be the same.
Furthermore, the 3 variants suggest they're only valid for those 3
atomic ops, while we have many more where they could be applied.
So move away from
smp_mb__{before,after}_{atomic,clear}_{dec,inc,bit}() and reduce the
interface to just the two: smp_mb__{before,after}_atomic().
This patch prepares the way by introducing default implementations in
asm-generic/barrier.h that default to a full barrier and providing
__deprecated inlines for the previous 6 barriers if they're not
provided by the arch.
This should allow for a mostly painless transition (lots of deprecated
warns in the interim).
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-wr59327qdyi9mbzn6x937s4e@git.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Chen, Gong" <gong.chen@linux.intel.com>
Cc: John Sullivan <jsrhbz@kanargh.force9.co.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
90 lines
2.0 KiB
C
90 lines
2.0 KiB
C
/*
|
|
* Generic barrier definitions, originally based on MN10300 definitions.
|
|
*
|
|
* It should be possible to use these on really simple architectures,
|
|
* but it serves more as a starting point for new ports.
|
|
*
|
|
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
|
|
* Written by David Howells (dhowells@redhat.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public Licence
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the Licence, or (at your option) any later version.
|
|
*/
|
|
#ifndef __ASM_GENERIC_BARRIER_H
|
|
#define __ASM_GENERIC_BARRIER_H
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
#include <linux/compiler.h>
|
|
|
|
#ifndef nop
|
|
#define nop() asm volatile ("nop")
|
|
#endif
|
|
|
|
/*
|
|
* Force strict CPU ordering. And yes, this is required on UP too when we're
|
|
* talking to devices.
|
|
*
|
|
* Fall back to compiler barriers if nothing better is provided.
|
|
*/
|
|
|
|
#ifndef mb
|
|
#define mb() barrier()
|
|
#endif
|
|
|
|
#ifndef rmb
|
|
#define rmb() mb()
|
|
#endif
|
|
|
|
#ifndef wmb
|
|
#define wmb() mb()
|
|
#endif
|
|
|
|
#ifndef read_barrier_depends
|
|
#define read_barrier_depends() do { } while (0)
|
|
#endif
|
|
|
|
#ifdef CONFIG_SMP
|
|
#define smp_mb() mb()
|
|
#define smp_rmb() rmb()
|
|
#define smp_wmb() wmb()
|
|
#define smp_read_barrier_depends() read_barrier_depends()
|
|
#else
|
|
#define smp_mb() barrier()
|
|
#define smp_rmb() barrier()
|
|
#define smp_wmb() barrier()
|
|
#define smp_read_barrier_depends() do { } while (0)
|
|
#endif
|
|
|
|
#ifndef set_mb
|
|
#define set_mb(var, value) do { (var) = (value); mb(); } while (0)
|
|
#endif
|
|
|
|
#ifndef smp_mb__before_atomic
|
|
#define smp_mb__before_atomic() smp_mb()
|
|
#endif
|
|
|
|
#ifndef smp_mb__after_atomic
|
|
#define smp_mb__after_atomic() smp_mb()
|
|
#endif
|
|
|
|
#define smp_store_release(p, v) \
|
|
do { \
|
|
compiletime_assert_atomic_type(*p); \
|
|
smp_mb(); \
|
|
ACCESS_ONCE(*p) = (v); \
|
|
} while (0)
|
|
|
|
#define smp_load_acquire(p) \
|
|
({ \
|
|
typeof(*p) ___p1 = ACCESS_ONCE(*p); \
|
|
compiletime_assert_atomic_type(*p); \
|
|
smp_mb(); \
|
|
___p1; \
|
|
})
|
|
|
|
#endif /* !__ASSEMBLY__ */
|
|
#endif /* __ASM_GENERIC_BARRIER_H */
|