linux-kernel - [PATCH 13/37] MIPS: atomic: Use _atomic barriers in atomic_sub_if

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Date:   Mon, 30 Sep 2019 23:08:25 +0000
From:   Paul Burton <paul.burton@...s.com>
To:     "linux-mips@...r.kernel.org" <linux-mips@...r.kernel.org>
CC:     Huacai Chen <chenhc@...ote.com>,
        Jiaxun Yang <jiaxun.yang@...goat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Paul Burton <pburton@...ecomp.com>
Subject: [PATCH 13/37] MIPS: atomic: Use _atomic barriers in
 atomic_sub_if_positive()

Use smp_mb__before_atomic() & smp_mb__after_atomic() in
atomic_sub_if_positive() rather than the equivalent
smp_mb__before_llsc() & smp_llsc_mb(). The former are more standard &
this preps us for avoiding redundant duplicate barriers on Loongson3 in
a later patch.

Signed-off-by: Paul Burton <paul.burton@...s.com>
---

 arch/mips/include/asm/atomic.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h
index 841ff274ada6..24443ef29337 100644
--- a/arch/mips/include/asm/atomic.h
+++ b/arch/mips/include/asm/atomic.h
@@ -196,7 +196,7 @@ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
 {
 	int result;
 
-	smp_mb__before_llsc();
+	smp_mb__before_atomic();
 
 	if (kernel_uses_llsc) {
 		int temp;
@@ -237,7 +237,7 @@ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
 	 * another barrier here.
 	 */
 	if (!__SYNC_loongson3_war)
-		smp_llsc_mb();
+		smp_mb__after_atomic();
 
 	return result;
 }
-- 
2.23.0