On 02/06/15 01:09, Leonid Yegoshin wrote:
> Repleace smp_mb() in arch_write_unlock() and __clear_bit_unlock() to
Replace.
> 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.
>
> Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@xxxxxxxxxx>
> ---
> 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();
arch_write_unlock appears to just use sw, not sc, and __clear_bit
appears to be implemented in plain C, so is smp_mb__before_llsc() really
appropriate? Would smp_release() be more accurate/correct in both cases?
Cheers
James
>
> __asm__ __volatile__(
> " # arch_write_unlock \n"
>
>
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