openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

parisc: implement atomic64_dec_if_positive() 

Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Helge Deller 2013-05-06 19:13:33 +00:00
parent bbbfde7820
commit f21dda025a
2 changed files with 24 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/parisc/Kconfig
View File

@ -13,6 +13,7 @@ config PARISC
select BUG
select HAVE_PERF_EVENTS
select GENERIC_ATOMIC64 if !64BIT
select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
select HAVE_GENERIC_HARDIRQS
select BROKEN_RODATA
select GENERIC_IRQ_PROBE

23
arch/parisc/include/asm/atomic.h
View File

@ -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)
/*
* 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 */