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arch,s390: Convert smp_mb__*() 

As per the existing implementation; implement the new one using
smp_mb().

AFAICT the s390 compare-and-swap does imply a barrier, however there
are some immediate ops that seem to be singly-copy atomic and do not
imply a barrier. One such is the "ni" op (which would be
and-immediate) which is used for the constant clear_bit
implementation. Therefore s390 needs full barriers for the
{before,after} atomic ops.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-kme5dz5hcobpnufnnkh1ech2@git.kernel.org
Cc: Chen Gang <gang.chen@asianux.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux390@de.ibm.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Peter Zijlstra 2014-03-13 19:00:35 +01:00 committed by Ingo Molnar
parent c645073f7e
commit 0e530747c6
2 changed files with 3 additions and 7 deletions
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5
arch/s390/include/asm/atomic.h
View File

@ -412,9 +412,4 @@ static inline long long atomic64_dec_if_positive(atomic64_t *v)
#define atomic64_dec_and_test(_v) (atomic64_sub_return(1, _v) == 0)
#define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
#define smp_mb__before_atomic_dec() smp_mb()
#define smp_mb__after_atomic_dec() smp_mb()
#define smp_mb__before_atomic_inc() smp_mb()
#define smp_mb__after_atomic_inc() smp_mb()
#endif /* __ARCH_S390_ATOMIC__ */

5
arch/s390/include/asm/barrier.h
View File

@ -27,8 +27,9 @@
#define smp_rmb() rmb()
#define smp_wmb() wmb()
#define smp_read_barrier_depends() read_barrier_depends()
#define smp_mb__before_clear_bit() smp_mb()
#define smp_mb__after_clear_bit() smp_mb()
#define smp_mb__before_atomic() smp_mb()
#define smp_mb__after_atomic() smp_mb()
#define set_mb(var, value) do { var = value; mb(); } while (0)