diff options
| -rw-r--r-- | arch/s390/include/asm/atomic.h | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/s390/include/asm/atomic.h b/arch/s390/include/asm/atomic.h index 451bfbb..76daea1 100644 --- a/arch/s390/include/asm/atomic.h +++ b/arch/s390/include/asm/atomic.h @@ -15,6 +15,7 @@ #include <linux/compiler.h> #include <linux/types.h> +#include <asm/system.h> #define ATOMIC_INIT(i) { (i) } @@ -274,6 +275,7 @@ static inline void atomic64_clear_mask(unsigned long long mask, atomic64_t *v) static inline int atomic64_add_unless(atomic64_t *v, long long a, long long u) { long long c, old; + c = atomic64_read(v); for (;;) { if (unlikely(c == u)) @@ -286,6 +288,23 @@ static inline int atomic64_add_unless(atomic64_t *v, long long a, long long u) return c != u; } +static inline long long atomic64_dec_if_positive(atomic64_t *v) +{ + long 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; +} + #define atomic64_add(_i, _v) atomic64_add_return(_i, _v) #define atomic64_add_negative(_i, _v) (atomic64_add_return(_i, _v) < 0) #define atomic64_inc(_v) atomic64_add_return(1, _v) |