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Commit 445ed0a0 authored by Vineet Gupta's avatar Vineet Gupta Committed by Linus Torvalds
Browse files

ia64: implement atomic64_dec_if_positive 

This is based on s390 version and needed to get rid of
CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE

Link: http://lkml.kernel.org/r/1473703083-8625-2-git-send-email-vgupta@synopsys.com


Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
Reported-by: default avatarkbuild test robot <fengguang.wu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1061b0d2

arch/ia64/include/asm/atomic.h

+16 −0
Original line number Diff line number Diff line
@@ -269,6 +269,22 @@ static __inline__ long atomic64_add_unless(atomic64_t *v, long a, long u) 


#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)



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;

}



/*

 * Atomically add I to V and return TRUE if the resulting value is

 * negative.