Commit f21dda02 authored by Helge Deller's avatar Helge Deller

parisc: implement atomic64_dec_if_positive()

Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent bbbfde78
...@@ -13,6 +13,7 @@ config PARISC ...@@ -13,6 +13,7 @@ config PARISC
select BUG select BUG
select HAVE_PERF_EVENTS select HAVE_PERF_EVENTS
select GENERIC_ATOMIC64 if !64BIT select GENERIC_ATOMIC64 if !64BIT
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select HAVE_GENERIC_HARDIRQS select HAVE_GENERIC_HARDIRQS
select BROKEN_RODATA select BROKEN_RODATA
select GENERIC_IRQ_PROBE select GENERIC_IRQ_PROBE
......
...@@ -229,6 +229,29 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u) ...@@ -229,6 +229,29 @@ 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) #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 /* !CONFIG_64BIT */ #endif /* !CONFIG_64BIT */
......
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