From: Vineet Gupta <Vineet.Gupta1@xxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxx Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx> Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/ia64/include/asm/atomic.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff -puN arch/ia64/include/asm/atomic.h~ia64-implement-atomic64_dec_if_positive arch/ia64/include/asm/atomic.h --- a/arch/ia64/include/asm/atomic.h~ia64-implement-atomic64_dec_if_positive +++ a/arch/ia64/include/asm/atomic.h @@ -269,6 +269,22 @@ static __inline__ long atomic64_add_unle #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. _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
