linux-kernel - [PATCH 28/37] MIPS: bitops: Use smp_mb__before_atomic in test

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Date:   Mon, 30 Sep 2019 23:08:38 +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 28/37] MIPS: bitops: Use smp_mb__before_atomic in test_* ops

Use smp_mb__before_atomic() rather than smp_mb__before_llsc() in
test_and_set_bit(), test_and_clear_bit() & test_and_change_bit(). The
_atomic() versions make semantic sense in these cases, and will allow a
later patch to omit redundant barriers for Loongson3 systems that
already include a barrier within __test_bit_op().

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

 arch/mips/include/asm/bitops.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h
index 9e967d6622c8..e6d97238a321 100644
--- a/arch/mips/include/asm/bitops.h
+++ b/arch/mips/include/asm/bitops.h
@@ -209,7 +209,7 @@ static inline int test_and_set_bit_lock(unsigned long nr,
 static inline int test_and_set_bit(unsigned long nr,
 	volatile unsigned long *addr)
 {
-	smp_mb__before_llsc();
+	smp_mb__before_atomic();
 	return test_and_set_bit_lock(nr, addr);
 }
 
@@ -228,7 +228,7 @@ static inline int test_and_clear_bit(unsigned long nr,
 	int bit = nr % BITS_PER_LONG;
 	unsigned long res, orig;
 
-	smp_mb__before_llsc();
+	smp_mb__before_atomic();
 
 	if (!kernel_uses_llsc) {
 		res = __mips_test_and_clear_bit(nr, addr);
@@ -265,7 +265,7 @@ static inline int test_and_change_bit(unsigned long nr,
 	int bit = nr % BITS_PER_LONG;
 	unsigned long res, orig;
 
-	smp_mb__before_llsc();
+	smp_mb__before_atomic();
 
 	if (!kernel_uses_llsc) {
 		res = __mips_test_and_change_bit(nr, addr);
-- 
2.23.0