![Linus Torvalds](/assets/img/avatar_default.png)
* 'x86-atomic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix LOCK_PREFIX_HERE for uniprocessor build x86, atomic64: In selftest, distinguish x86-64 from 586+ x86-32: Fix atomic64_inc_not_zero return value convention lib: Fix atomic64_inc_not_zero test lib: Fix atomic64_add_unless return value convention x86-32: Fix atomic64_add_unless return value convention lib: Fix atomic64_add_unless test x86: Implement atomic[64]_dec_if_positive() lib: Only test atomic64_dec_if_positive on archs having it x86-32: Rewrite 32-bit atomic64 functions in assembly lib: Add self-test for atomic64_t x86-32: Allow UP/SMP lock replacement in cmpxchg64 x86: Add support for lock prefix in alternatives
248 lines
5.5 KiB
C
248 lines
5.5 KiB
C
#ifndef _ASM_X86_ATOMIC64_64_H
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#define _ASM_X86_ATOMIC64_64_H
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#include <linux/types.h>
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#include <asm/alternative.h>
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#include <asm/cmpxchg.h>
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/* The 64-bit atomic type */
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#define ATOMIC64_INIT(i) { (i) }
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/**
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* atomic64_read - read atomic64 variable
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* @v: pointer of type atomic64_t
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*
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* Atomically reads the value of @v.
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* Doesn't imply a read memory barrier.
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*/
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static inline long atomic64_read(const atomic64_t *v)
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{
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return (*(volatile long *)&(v)->counter);
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}
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/**
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* atomic64_set - set atomic64 variable
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* @v: pointer to type atomic64_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i.
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*/
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static inline void atomic64_set(atomic64_t *v, long i)
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{
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v->counter = i;
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}
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/**
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* atomic64_add - add integer to atomic64 variable
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* @i: integer value to add
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* @v: pointer to type atomic64_t
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*
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* Atomically adds @i to @v.
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*/
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static inline void atomic64_add(long i, atomic64_t *v)
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{
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asm volatile(LOCK_PREFIX "addq %1,%0"
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: "=m" (v->counter)
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: "er" (i), "m" (v->counter));
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}
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/**
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* atomic64_sub - subtract the atomic64 variable
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* @i: integer value to subtract
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* @v: pointer to type atomic64_t
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*
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* Atomically subtracts @i from @v.
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*/
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static inline void atomic64_sub(long i, atomic64_t *v)
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{
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asm volatile(LOCK_PREFIX "subq %1,%0"
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: "=m" (v->counter)
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: "er" (i), "m" (v->counter));
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}
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/**
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* atomic64_sub_and_test - subtract value from variable and test result
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* @i: integer value to subtract
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* @v: pointer to type atomic64_t
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*
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* Atomically subtracts @i from @v and returns
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* true if the result is zero, or false for all
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* other cases.
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*/
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static inline int atomic64_sub_and_test(long i, atomic64_t *v)
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{
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unsigned char c;
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asm volatile(LOCK_PREFIX "subq %2,%0; sete %1"
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: "=m" (v->counter), "=qm" (c)
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: "er" (i), "m" (v->counter) : "memory");
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return c;
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}
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/**
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* atomic64_inc - increment atomic64 variable
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* @v: pointer to type atomic64_t
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*
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* Atomically increments @v by 1.
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*/
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static inline void atomic64_inc(atomic64_t *v)
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{
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asm volatile(LOCK_PREFIX "incq %0"
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: "=m" (v->counter)
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: "m" (v->counter));
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}
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/**
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* atomic64_dec - decrement atomic64 variable
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* @v: pointer to type atomic64_t
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*
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* Atomically decrements @v by 1.
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*/
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static inline void atomic64_dec(atomic64_t *v)
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{
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asm volatile(LOCK_PREFIX "decq %0"
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: "=m" (v->counter)
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: "m" (v->counter));
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}
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/**
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* atomic64_dec_and_test - decrement and test
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* @v: pointer to type atomic64_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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static inline int atomic64_dec_and_test(atomic64_t *v)
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{
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unsigned char c;
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asm volatile(LOCK_PREFIX "decq %0; sete %1"
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: "=m" (v->counter), "=qm" (c)
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: "m" (v->counter) : "memory");
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return c != 0;
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}
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/**
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* atomic64_inc_and_test - increment and test
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* @v: pointer to type atomic64_t
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*
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* Atomically increments @v by 1
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* and returns true if the result is zero, or false for all
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* other cases.
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*/
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static inline int atomic64_inc_and_test(atomic64_t *v)
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{
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unsigned char c;
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asm volatile(LOCK_PREFIX "incq %0; sete %1"
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: "=m" (v->counter), "=qm" (c)
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: "m" (v->counter) : "memory");
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return c != 0;
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}
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/**
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* atomic64_add_negative - add and test if negative
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* @i: integer value to add
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* @v: pointer to type atomic64_t
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*
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* Atomically adds @i to @v and returns true
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* if the result is negative, or false when
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* result is greater than or equal to zero.
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*/
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static inline int atomic64_add_negative(long i, atomic64_t *v)
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{
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unsigned char c;
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asm volatile(LOCK_PREFIX "addq %2,%0; sets %1"
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: "=m" (v->counter), "=qm" (c)
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: "er" (i), "m" (v->counter) : "memory");
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return c;
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}
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/**
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* atomic64_add_return - add and return
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* @i: integer value to add
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* @v: pointer to type atomic64_t
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*
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* Atomically adds @i to @v and returns @i + @v
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*/
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static inline long atomic64_add_return(long i, atomic64_t *v)
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{
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long __i = i;
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asm volatile(LOCK_PREFIX "xaddq %0, %1;"
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: "+r" (i), "+m" (v->counter)
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: : "memory");
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return i + __i;
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}
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static inline long atomic64_sub_return(long i, atomic64_t *v)
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{
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return atomic64_add_return(-i, v);
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}
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#define atomic64_inc_return(v) (atomic64_add_return(1, (v)))
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#define atomic64_dec_return(v) (atomic64_sub_return(1, (v)))
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static inline long atomic64_cmpxchg(atomic64_t *v, long old, long new)
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{
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return cmpxchg(&v->counter, old, new);
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}
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static inline long atomic64_xchg(atomic64_t *v, long new)
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{
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return xchg(&v->counter, new);
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}
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/**
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* atomic64_add_unless - add unless the number is a given value
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* @v: pointer of type atomic64_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 non-zero if @v was not @u, and zero otherwise.
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*/
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static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
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{
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long c, old;
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c = atomic64_read(v);
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for (;;) {
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if (unlikely(c == (u)))
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break;
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old = atomic64_cmpxchg((v), c, c + (a));
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if (likely(old == c))
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break;
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c = old;
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}
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return c != (u);
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}
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#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
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/*
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* atomic64_dec_if_positive - decrement by 1 if old value positive
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* @v: pointer of type atomic_t
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*
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* The function returns the old value of *v minus 1, even if
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* the atomic variable, v, was not decremented.
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*/
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static inline long atomic64_dec_if_positive(atomic64_t *v)
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{
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long c, old, dec;
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c = atomic64_read(v);
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for (;;) {
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dec = c - 1;
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if (unlikely(dec < 0))
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break;
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old = atomic64_cmpxchg((v), c, dec);
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if (likely(old == c))
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break;
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c = old;
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}
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return dec;
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}
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#endif /* _ASM_X86_ATOMIC64_64_H */
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