diff options
Diffstat (limited to 'arch/x86/include/asm/atomic64_64.h')
| -rw-r--r-- | arch/x86/include/asm/atomic64_64.h | 61 |
1 files changed, 30 insertions, 31 deletions
diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h index 51c5b405692..46e9052bbd2 100644 --- a/arch/x86/include/asm/atomic64_64.h +++ b/arch/x86/include/asm/atomic64_64.h @@ -18,7 +18,7 @@ */ static inline long atomic64_read(const atomic64_t *v) { - return v->counter; + return (*(volatile long *)&(v)->counter); } /** @@ -72,12 +72,7 @@ static inline void atomic64_sub(long i, atomic64_t *v) */ static inline int atomic64_sub_and_test(long i, atomic64_t *v) { - unsigned char c; - - asm volatile(LOCK_PREFIX "subq %2,%0; sete %1" - : "=m" (v->counter), "=qm" (c) - : "er" (i), "m" (v->counter) : "memory"); - return c; + GEN_BINARY_RMWcc(LOCK_PREFIX "subq", v->counter, "er", i, "%0", "e"); } /** @@ -116,12 +111,7 @@ static inline void atomic64_dec(atomic64_t *v) */ static inline int atomic64_dec_and_test(atomic64_t *v) { - unsigned char c; - - asm volatile(LOCK_PREFIX "decq %0; sete %1" - : "=m" (v->counter), "=qm" (c) - : "m" (v->counter) : "memory"); - return c != 0; + GEN_UNARY_RMWcc(LOCK_PREFIX "decq", v->counter, "%0", "e"); } /** @@ -134,12 +124,7 @@ static inline int atomic64_dec_and_test(atomic64_t *v) */ static inline int atomic64_inc_and_test(atomic64_t *v) { - unsigned char c; - - asm volatile(LOCK_PREFIX "incq %0; sete %1" - : "=m" (v->counter), "=qm" (c) - : "m" (v->counter) : "memory"); - return c != 0; + GEN_UNARY_RMWcc(LOCK_PREFIX "incq", v->counter, "%0", "e"); } /** @@ -153,12 +138,7 @@ static inline int atomic64_inc_and_test(atomic64_t *v) */ static inline int atomic64_add_negative(long i, atomic64_t *v) { - unsigned char c; - - asm volatile(LOCK_PREFIX "addq %2,%0; sets %1" - : "=m" (v->counter), "=qm" (c) - : "er" (i), "m" (v->counter) : "memory"); - return c; + GEN_BINARY_RMWcc(LOCK_PREFIX "addq", v->counter, "er", i, "%0", "s"); } /** @@ -170,11 +150,7 @@ static inline int atomic64_add_negative(long i, atomic64_t *v) */ static inline long atomic64_add_return(long i, atomic64_t *v) { - long __i = i; - asm volatile(LOCK_PREFIX "xaddq %0, %1;" - : "+r" (i), "+m" (v->counter) - : : "memory"); - return i + __i; + return i + xadd(&v->counter, i); } static inline long atomic64_sub_return(long i, atomic64_t *v) @@ -202,7 +178,7 @@ static inline long atomic64_xchg(atomic64_t *v, long new) * @u: ...unless v is equal to u. * * Atomically adds @a to @v, so long as it was not @u. - * Returns non-zero if @v was not @u, and zero otherwise. + * Returns the old value of @v. */ static inline int atomic64_add_unless(atomic64_t *v, long a, long u) { @@ -221,4 +197,27 @@ static inline int atomic64_add_unless(atomic64_t *v, long a, long u) #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0) +/* + * atomic64_dec_if_positive - decrement by 1 if old value positive + * @v: pointer of type atomic_t + * + * The function returns the old value of *v minus 1, even if + * the atomic variable, v, was not decremented. + */ +static inline long atomic64_dec_if_positive(atomic64_t *v) +{ + long c, old, dec; + c = atomic64_read(v); + for (;;) { + dec = c - 1; + if (unlikely(dec < 0)) + break; + old = atomic64_cmpxchg((v), c, dec); + if (likely(old == c)) + break; + c = old; + } + return dec; +} + #endif /* _ASM_X86_ATOMIC64_64_H */ |