On Tue, Jun 02, 2015 at 12:42:40PM +0100, James Hogan wrote:
> 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?
Yes on the both questions.
Ralf
