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 --- arch/s390/include/asm/atomic.h | 6 +----- arch/s390/include/asm/barrier.h | 5 +++-- arch/s390/include/asm/bitops.h | 1 + 3 files changed, 5 insertions(+), 7 deletions(-) --- a/arch/s390/include/asm/atomic.h +++ b/arch/s390/include/asm/atomic.h @@ -16,6 +16,7 @@ #include #include #include +#include #define ATOMIC_INIT(i) { (i) } @@ -398,9 +399,4 @@ static inline long long atomic64_dec_if_ #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__ */ --- a/arch/s390/include/asm/barrier.h +++ b/arch/s390/include/asm/barrier.h @@ -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) --- a/arch/s390/include/asm/bitops.h +++ b/arch/s390/include/asm/bitops.h @@ -47,6 +47,7 @@ #include #include +#include #ifndef CONFIG_64BIT -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/