diff options
| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2010-05-26 23:26:18 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com> | 2010-05-26 23:26:29 +0200 |
| commit | 2ddb3ec41495c2f4535d1e72e21e25870117f848 (patch) | |
| tree | b8625f5b0b56ca212382cd3f7ea8b62e877061ec /arch | |
| parent | 1ef6acf597559fd1c244190512144c40619299bf (diff) | |
[S390] atomic: implement atomic64_dec_if_positive
Implement atomic64_dec_if_positive and add missing system.h header
include.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch')
| -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 451bfbb9db3..76daea11718 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) |