Messages in this thread | | | Date | Tue, 2 Jun 2015 12:42:40 +0100 | From | James Hogan <> | Subject | Re: [PATCH 3/3] MIPS: bugfix - replace smp_mb with release barrier function in unlocks |
| |
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@imgtec.com> > --- > 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" > >
[unhandled content-type:application/pgp-signature] | |