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Commit adf6d9b3 authored by Chris Metcalf's avatar Chris Metcalf
Browse files

tile: support atomic64_dec_if_positive() 



Use the normal cmpxchg() idiom to implement this functionality.

Signed-off-by: default avatarChris Metcalf <cmetcalf@tilera.com>
parent ef567f25

arch/tile/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ config TILE 
	select MODULES_USE_ELF_RELA

	select HAVE_ARCH_TRACEHOOK

	select HAVE_SYSCALL_TRACEPOINTS

	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE



# FIXME: investigate whether we need/want these options.

#	select HAVE_IOREMAP_PROT

arch/tile/include/asm/atomic.h

+21 −0
Original line number Diff line number Diff line
@@ -131,4 +131,25 @@ static inline int atomic_read(const atomic_t *v) 
#include <asm/atomic_64.h>

#endif



#ifndef __ASSEMBLY__



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;

}



#endif /* __ASSEMBLY__ */



#endif /* _ASM_TILE_ATOMIC_H */