Messages in this thread Patch in this message | | | From | Vineet Gupta <> | Subject | [PATCH v2 1/2] ia64: implement atomic64_dec_if_positive | Date | Mon, 12 Sep 2016 10:47:11 -0700 |
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This is based on s390 version and needed to get rid of CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
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> Cc: linux-ia64@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Vineet Gupta <vgupta@synopsys.com> --- arch/ia64/include/asm/atomic.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/arch/ia64/include/asm/atomic.h b/arch/ia64/include/asm/atomic.h index f565ad376142..65d4bb2b6685 100644 --- a/arch/ia64/include/asm/atomic.h +++ b/arch/ia64/include/asm/atomic.h @@ -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. -- 2.7.4
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