forked from luck/tmp_suning_uos_patched
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: Vineet Gupta <vgupta@synopsys.com> Reported-by: kbuild 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -269,6 +269,22 @@ static __inline__ long atomic64_add_unless(atomic64_t *v, long a, long u)
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#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
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static __inline__ long atomic64_dec_if_positive(atomic64_t *v)
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{
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long c, old, dec;
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c = atomic64_read(v);
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for (;;) {
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dec = c - 1;
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if (unlikely(dec < 0))
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break;
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old = atomic64_cmpxchg((v), c, dec);
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if (likely(old == c))
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break;
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c = old;
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}
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return dec;
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}
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/*
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* Atomically add I to V and return TRUE if the resulting value is
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* negative.
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