MIPS: bitops: Use smp_mb__before_atomic in test_* ops (90267377) · Commits · 戴 / test

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@mips.com> Cc: linux-mips@vger.kernel.org Cc: Huacai Chen <chenhc@lemote.com> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: linux-kernel@vger.kernel.org

arch/mips/include/asm/bitops.h

+3 −3

Original line number	Diff line number	Diff line
		@@ -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);

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