2005-04-17 06:20:36 +08:00
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/*
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2008-08-02 17:55:55 +08:00
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* arch/arm/include/asm/atomic.h
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2005-04-17 06:20:36 +08:00
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*
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* Copyright (C) 1996 Russell King.
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* Copyright (C) 2002 Deep Blue Solutions Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __ASM_ARM_ATOMIC_H
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#define __ASM_ARM_ATOMIC_H
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2005-11-17 01:23:57 +08:00
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#include <linux/compiler.h>
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2009-01-07 06:40:39 +08:00
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#include <linux/types.h>
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2007-05-08 15:34:38 +08:00
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#include <asm/system.h>
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2005-04-17 06:20:36 +08:00
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#define ATOMIC_INIT(i) { (i) }
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#ifdef __KERNEL__
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#define atomic_read(v) ((v)->counter)
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#if __LINUX_ARM_ARCH__ >= 6
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/*
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* ARMv6 UP and SMP safe atomic ops. We use load exclusive and
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* store exclusive to ensure that these are atomic. We may loop
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* to ensure that the update happens. Writing to 'v->counter'
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* without using the following operations WILL break the atomic
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* nature of these ops.
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*/
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static inline void atomic_set(atomic_t *v, int i)
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{
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unsigned long tmp;
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__asm__ __volatile__("@ atomic_set\n"
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"1: ldrex %0, [%1]\n"
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" strex %0, %2, [%1]\n"
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" teq %0, #0\n"
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" bne 1b"
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: "=&r" (tmp)
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: "r" (&v->counter), "r" (i)
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: "cc");
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}
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static inline int atomic_add_return(int i, atomic_t *v)
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{
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unsigned long tmp;
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int result;
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__asm__ __volatile__("@ atomic_add_return\n"
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"1: ldrex %0, [%2]\n"
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" add %0, %0, %3\n"
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" strex %1, %0, [%2]\n"
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" teq %1, #0\n"
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" bne 1b"
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: "=&r" (result), "=&r" (tmp)
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: "r" (&v->counter), "Ir" (i)
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: "cc");
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return result;
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}
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static inline int atomic_sub_return(int i, atomic_t *v)
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{
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unsigned long tmp;
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int result;
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__asm__ __volatile__("@ atomic_sub_return\n"
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"1: ldrex %0, [%2]\n"
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" sub %0, %0, %3\n"
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" strex %1, %0, [%2]\n"
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" teq %1, #0\n"
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" bne 1b"
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: "=&r" (result), "=&r" (tmp)
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: "r" (&v->counter), "Ir" (i)
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: "cc");
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return result;
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}
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2005-11-14 08:07:24 +08:00
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static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new)
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{
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2005-11-17 02:03:10 +08:00
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unsigned long oldval, res;
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2005-11-14 08:07:24 +08:00
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do {
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__asm__ __volatile__("@ atomic_cmpxchg\n"
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"ldrex %1, [%2]\n"
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2005-11-16 23:05:11 +08:00
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"mov %0, #0\n"
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2005-11-14 08:07:24 +08:00
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"teq %1, %3\n"
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"strexeq %0, %4, [%2]\n"
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: "=&r" (res), "=&r" (oldval)
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: "r" (&ptr->counter), "Ir" (old), "r" (new)
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: "cc");
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} while (res);
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return oldval;
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}
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2005-04-17 06:20:36 +08:00
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static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
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{
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unsigned long tmp, tmp2;
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__asm__ __volatile__("@ atomic_clear_mask\n"
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2007-03-15 23:54:27 +08:00
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"1: ldrex %0, [%2]\n"
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2005-04-17 06:20:36 +08:00
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" bic %0, %0, %3\n"
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2007-03-15 23:54:27 +08:00
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" strex %1, %0, [%2]\n"
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2005-04-17 06:20:36 +08:00
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" teq %1, #0\n"
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" bne 1b"
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: "=&r" (tmp), "=&r" (tmp2)
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: "r" (addr), "Ir" (mask)
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: "cc");
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}
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#else /* ARM_ARCH_6 */
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#include <asm/system.h>
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#ifdef CONFIG_SMP
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#error SMP not supported on pre-ARMv6 CPUs
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#endif
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#define atomic_set(v,i) (((v)->counter) = (i))
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static inline int atomic_add_return(int i, atomic_t *v)
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{
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unsigned long flags;
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int val;
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2006-09-16 17:47:18 +08:00
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raw_local_irq_save(flags);
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2005-04-17 06:20:36 +08:00
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val = v->counter;
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v->counter = val += i;
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2006-09-16 17:47:18 +08:00
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raw_local_irq_restore(flags);
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2005-04-17 06:20:36 +08:00
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return val;
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}
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static inline int atomic_sub_return(int i, atomic_t *v)
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{
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unsigned long flags;
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int val;
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2006-09-16 17:47:18 +08:00
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raw_local_irq_save(flags);
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2005-04-17 06:20:36 +08:00
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val = v->counter;
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v->counter = val -= i;
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2006-09-16 17:47:18 +08:00
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raw_local_irq_restore(flags);
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2005-04-17 06:20:36 +08:00
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return val;
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}
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2005-11-14 08:07:24 +08:00
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static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
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{
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int ret;
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unsigned long flags;
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2006-09-16 17:47:18 +08:00
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raw_local_irq_save(flags);
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2005-11-14 08:07:24 +08:00
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ret = v->counter;
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if (likely(ret == old))
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v->counter = new;
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2006-09-16 17:47:18 +08:00
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raw_local_irq_restore(flags);
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2005-11-14 08:07:24 +08:00
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return ret;
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}
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2005-04-17 06:20:36 +08:00
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static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
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{
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unsigned long flags;
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2006-09-16 17:47:18 +08:00
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raw_local_irq_save(flags);
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2005-04-17 06:20:36 +08:00
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*addr &= ~mask;
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2006-09-16 17:47:18 +08:00
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raw_local_irq_restore(flags);
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2005-04-17 06:20:36 +08:00
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}
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#endif /* __LINUX_ARM_ARCH__ */
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2006-01-10 07:59:17 +08:00
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#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
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2005-11-14 08:07:25 +08:00
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static inline int atomic_add_unless(atomic_t *v, int a, int u)
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{
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int c, old;
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c = atomic_read(v);
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while (c != u && (old = atomic_cmpxchg((v), c, c + a)) != c)
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c = old;
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return c != u;
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}
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#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
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2005-04-17 06:20:36 +08:00
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#define atomic_add(i, v) (void) atomic_add_return(i, v)
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#define atomic_inc(v) (void) atomic_add_return(1, v)
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#define atomic_sub(i, v) (void) atomic_sub_return(i, v)
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#define atomic_dec(v) (void) atomic_sub_return(1, v)
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#define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0)
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#define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0)
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#define atomic_inc_return(v) (atomic_add_return(1, v))
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#define atomic_dec_return(v) (atomic_sub_return(1, v))
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#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)
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#define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0)
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/* Atomic operations are already serializing on ARM */
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#define smp_mb__before_atomic_dec() barrier()
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#define smp_mb__after_atomic_dec() barrier()
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#define smp_mb__before_atomic_inc() barrier()
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#define smp_mb__after_atomic_inc() barrier()
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2006-01-06 16:11:20 +08:00
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#include <asm-generic/atomic.h>
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2005-04-17 06:20:36 +08:00
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#endif
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#endif
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