From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vineet Gupta Date: Mon, 12 Sep 2016 17:47:11 +0000 Subject: [PATCH v2 1/2] ia64: implement atomic64_dec_if_positive Message-Id: <1473702432-8116-2-git-send-email-vgupta@synopsys.com> List-Id: References: <1473702432-8116-1-git-send-email-vgupta@synopsys.com> In-Reply-To: <1473702432-8116-1-git-send-email-vgupta@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Tony Luck , Fenghua Yu , Ingo Molnar , Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-snps-arc@lists.infradead.org, Vineet Gupta , linux-ia64@vger.kernel.org This is based on s390 version and needed to get rid of CONFIG_ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE Cc: Tony Luck Cc: Fenghua Yu Cc: Ingo Molnar Cc: Peter Zijlstra Cc: linux-ia64@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Vineet Gupta --- 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