From 6f6ed482653723e53da4a57b200348ac1eed5ce9 Mon Sep 17 00:00:00 2001 From: Leonid Yegoshin Date: Mon, 1 Jun 2015 17:09:52 -0700 Subject: [PATCH] MIPS: Replace smp_mb with release barrier function in unlocks. Repleace smp_mb() in arch_write_unlock() and __clear_bit_unlock() to smp_mb__before_llsc() call which does "release" barrier functionality. It seems like it was missed in commit f252ffd50c97dae87b45f1dbad24f71358ccfbd6 during introduction of "acquire" and "release" semantics. [ralf@linux-mips: The original patch submission was labelled a fix but actually it replaces a barrier with another less restrictive type of barrier so it doesn't fix any ill behaviour but rather squeezes out a tad better performance. Further improvments will be possible once smp_release() has been merged.] Signed-off-by: Leonid Yegoshin Cc: linux-mips@linux-mips.org Cc: benh@kernel.crashing.org Cc: will.deacon@arm.com Cc: linux-kernel@vger.kernel.org Cc: markos.chandras@imgtec.com Cc: macro@linux-mips.org Cc: Steven.Hill@imgtec.com Cc: alexander.h.duyck@redhat.com Cc: davem@davemloft.net Patchwork: https://patchwork.linux-mips.org/patch/10507/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/bitops.h | 2 +- arch/mips/include/asm/spinlock.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/mips/include/asm/bitops.h b/arch/mips/include/asm/bitops.h index 0cf29bd5dc5c..ce9666cf1499 100644 --- a/arch/mips/include/asm/bitops.h +++ b/arch/mips/include/asm/bitops.h @@ -469,7 +469,7 @@ static inline int test_and_change_bit(unsigned long nr, */ static inline void __clear_bit_unlock(unsigned long nr, volatile unsigned long *addr) { - smp_mb(); + smp_mb__before_llsc(); __clear_bit(nr, addr); } diff --git a/arch/mips/include/asm/spinlock.h b/arch/mips/include/asm/spinlock.h index 1fca2e0793dc..7c7f3b2bd3de 100644 --- a/arch/mips/include/asm/spinlock.h +++ b/arch/mips/include/asm/spinlock.h @@ -317,7 +317,7 @@ static inline void arch_write_lock(arch_rwlock_t *rw) static inline void arch_write_unlock(arch_rwlock_t *rw) { - smp_mb(); + smp_mb__before_llsc(); __asm__ __volatile__( " # arch_write_unlock \n" -- 2.39.2