238 lines
6.0 KiB
C
238 lines
6.0 KiB
C
/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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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_ARC_ATOMIC_H
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#define _ASM_ARC_ATOMIC_H
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#include <linux/compiler.h>
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#include <asm/cmpxchg.h>
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#include <asm/barrier.h>
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#include <asm/smp.h>
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#define atomic_read(v) READ_ONCE((v)->counter)
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#ifdef CONFIG_ARC_HAS_LLSC
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#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
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#ifdef CONFIG_ARC_STAR_9000923308
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#define SCOND_FAIL_RETRY_VAR_DEF \
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unsigned int delay = 1, tmp; \
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#define SCOND_FAIL_RETRY_ASM \
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" bz 4f \n" \
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" ; --- scond fail delay --- \n" \
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" mov %[tmp], %[delay] \n" /* tmp = delay */ \
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"2: brne.d %[tmp], 0, 2b \n" /* while (tmp != 0) */ \
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" sub %[tmp], %[tmp], 1 \n" /* tmp-- */ \
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" rol %[delay], %[delay] \n" /* delay *= 2 */ \
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" b 1b \n" /* start over */ \
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"4: ; --- success --- \n" \
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#define SCOND_FAIL_RETRY_VARS \
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,[delay] "+&r" (delay),[tmp] "=&r" (tmp) \
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#else /* !CONFIG_ARC_STAR_9000923308 */
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#define SCOND_FAIL_RETRY_VAR_DEF
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#define SCOND_FAIL_RETRY_ASM \
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" bnz 1b \n" \
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#define SCOND_FAIL_RETRY_VARS
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#endif
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#define ATOMIC_OP(op, c_op, asm_op) \
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static inline void atomic_##op(int i, atomic_t *v) \
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{ \
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unsigned int val; \
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SCOND_FAIL_RETRY_VAR_DEF \
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\
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__asm__ __volatile__( \
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"1: llock %[val], [%[ctr]] \n" \
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" " #asm_op " %[val], %[val], %[i] \n" \
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" scond %[val], [%[ctr]] \n" \
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" \n" \
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SCOND_FAIL_RETRY_ASM \
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\
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: [val] "=&r" (val) /* Early clobber to prevent reg reuse */ \
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SCOND_FAIL_RETRY_VARS \
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: [ctr] "r" (&v->counter), /* Not "m": llock only supports reg direct addr mode */ \
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[i] "ir" (i) \
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: "cc"); \
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} \
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#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
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static inline int atomic_##op##_return(int i, atomic_t *v) \
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{ \
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unsigned int val; \
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SCOND_FAIL_RETRY_VAR_DEF \
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\
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/* \
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* Explicit full memory barrier needed before/after as \
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* LLOCK/SCOND thmeselves don't provide any such semantics \
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*/ \
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smp_mb(); \
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\
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__asm__ __volatile__( \
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"1: llock %[val], [%[ctr]] \n" \
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" " #asm_op " %[val], %[val], %[i] \n" \
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" scond %[val], [%[ctr]] \n" \
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" \n" \
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SCOND_FAIL_RETRY_ASM \
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\
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: [val] "=&r" (val) \
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SCOND_FAIL_RETRY_VARS \
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: [ctr] "r" (&v->counter), \
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[i] "ir" (i) \
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: "cc"); \
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\
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smp_mb(); \
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\
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return val; \
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}
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#else /* !CONFIG_ARC_HAS_LLSC */
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#ifndef CONFIG_SMP
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/* violating atomic_xxx API locking protocol in UP for optimization sake */
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#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
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#else
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static inline void atomic_set(atomic_t *v, int i)
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{
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/*
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* Independent of hardware support, all of the atomic_xxx() APIs need
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* to follow the same locking rules to make sure that a "hardware"
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* atomic insn (e.g. LD) doesn't clobber an "emulated" atomic insn
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* sequence
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*
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* Thus atomic_set() despite being 1 insn (and seemingly atomic)
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* requires the locking.
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*/
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unsigned long flags;
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atomic_ops_lock(flags);
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WRITE_ONCE(v->counter, i);
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atomic_ops_unlock(flags);
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}
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#endif
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/*
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* Non hardware assisted Atomic-R-M-W
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* Locking would change to irq-disabling only (UP) and spinlocks (SMP)
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*/
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#define ATOMIC_OP(op, c_op, asm_op) \
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static inline void atomic_##op(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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\
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atomic_ops_lock(flags); \
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v->counter c_op i; \
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atomic_ops_unlock(flags); \
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}
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#define ATOMIC_OP_RETURN(op, c_op, asm_op) \
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static inline int atomic_##op##_return(int i, atomic_t *v) \
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{ \
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unsigned long flags; \
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unsigned long temp; \
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\
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/* \
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* spin lock/unlock provides the needed smp_mb() before/after \
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*/ \
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atomic_ops_lock(flags); \
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temp = v->counter; \
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temp c_op i; \
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v->counter = temp; \
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atomic_ops_unlock(flags); \
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\
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return temp; \
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}
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#endif /* !CONFIG_ARC_HAS_LLSC */
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#define ATOMIC_OPS(op, c_op, asm_op) \
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ATOMIC_OP(op, c_op, asm_op) \
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ATOMIC_OP_RETURN(op, c_op, asm_op)
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ATOMIC_OPS(add, +=, add)
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ATOMIC_OPS(sub, -=, sub)
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#define atomic_andnot atomic_andnot
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ATOMIC_OP(and, &=, and)
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ATOMIC_OP(andnot, &= ~, bic)
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ATOMIC_OP(or, |=, or)
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ATOMIC_OP(xor, ^=, xor)
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#undef ATOMIC_OPS
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#undef ATOMIC_OP_RETURN
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#undef ATOMIC_OP
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#undef SCOND_FAIL_RETRY_VAR_DEF
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#undef SCOND_FAIL_RETRY_ASM
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#undef SCOND_FAIL_RETRY_VARS
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/**
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* __atomic_add_unless - add unless the number is a given value
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* @v: pointer of type atomic_t
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* @a: the amount to add to v...
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* @u: ...unless v is equal to u.
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*
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* Atomically adds @a to @v, so long as it was not @u.
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* Returns the old value of @v
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*/
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#define __atomic_add_unless(v, a, u) \
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({ \
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int c, old; \
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\
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/* \
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* Explicit full memory barrier needed before/after as \
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* LLOCK/SCOND thmeselves don't provide any such semantics \
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*/ \
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smp_mb(); \
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\
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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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\
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smp_mb(); \
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\
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c; \
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})
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#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
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#define atomic_inc(v) atomic_add(1, v)
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#define atomic_dec(v) atomic_sub(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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#define ATOMIC_INIT(i) { (i) }
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#include <asm-generic/atomic64.h>
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#endif
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#endif
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