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Commit 2ddb3ec4 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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[S390] atomic: implement atomic64_dec_if_positive 



Implement atomic64_dec_if_positive and add missing system.h header
include.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 1ef6acf5

arch/s390/include/asm/atomic.h

+19 −0
Original line number Diff line number Diff line
@@ -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)