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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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62e8a3258b
This patch makes sure that atomic_{read,set}() are at least {READ,WRITE}_ONCE(). We already had the 'requirement' that atomic_read() should use ACCESS_ONCE(), and most archs had this, but a few were lacking. All are now converted to use READ_ONCE(). And, by a symmetry and general paranoia argument, upgrade atomic_set() to use WRITE_ONCE(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: james.hogan@imgtec.com Cc: linux-kernel@vger.kernel.org Cc: oleg@redhat.com Cc: will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
239 lines
5.3 KiB
C
239 lines
5.3 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 READ_ONCE((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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WRITE_ONCE(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 __always_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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GEN_BINARY_RMWcc(LOCK_PREFIX "subq", v->counter, "er", i, "%0", "e");
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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 __always_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 __always_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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GEN_UNARY_RMWcc(LOCK_PREFIX "decq", v->counter, "%0", "e");
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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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GEN_UNARY_RMWcc(LOCK_PREFIX "incq", v->counter, "%0", "e");
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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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GEN_BINARY_RMWcc(LOCK_PREFIX "addq", v->counter, "er", i, "%0", "s");
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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 __always_inline long atomic64_add_return(long i, atomic64_t *v)
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{
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return i + xadd(&v->counter, 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 the old value of @v.
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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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#define ATOMIC64_OP(op) \
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static inline void atomic64_##op(long i, atomic64_t *v) \
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{ \
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asm volatile(LOCK_PREFIX #op"q %1,%0" \
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: "+m" (v->counter) \
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: "er" (i) \
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: "memory"); \
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}
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ATOMIC64_OP(and)
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ATOMIC64_OP(or)
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ATOMIC64_OP(xor)
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#undef ATOMIC64_OP
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#endif /* _ASM_X86_ATOMIC64_64_H */
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