On Wed, Mar 19, 2014 at 06:47:35AM +0000, Peter Zijlstra wrote:
> ARM uses ll/sc primitives that do not imply barriers for all regular
> atomic ops, therefore smp_mb__{before,after} need be a full barrier.
>
> Since ARM doesn't use asm-generic/barrier.h include the required
> definitions in its asm/barrier.h
>
> Signed-off-by: Peter Zijlstra <pet...@infradead.org>
Acked-by: Will Deacon <will.dea...@arm.com>
Will
> ---
> arch/arm/include/asm/atomic.h | 5 -----
> arch/arm/include/asm/barrier.h | 3 +++
> arch/arm/include/asm/bitops.h | 4 +---
> 3 files changed, 4 insertions(+), 8 deletions(-)
>
> --- a/arch/arm/include/asm/atomic.h
> +++ b/arch/arm/include/asm/atomic.h
> @@ -211,11 +211,6 @@ static inline int __atomic_add_unless(at
>
> #define atomic_add_negative(i,v) (atomic_add_return(i, v) < 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()
> -
> #ifndef CONFIG_GENERIC_ATOMIC64
> typedef struct {
> long long counter;
> --- a/arch/arm/include/asm/barrier.h
> +++ b/arch/arm/include/asm/barrier.h
> @@ -79,5 +79,8 @@ do {
> \
>
> #define set_mb(var, value) do { var = value; smp_mb(); } while (0)
>
> +#define smp_mb__before_atomic() smp_mb()
> +#define smp_mb__after_atomic() smp_mb()
> +
> #endif /* !__ASSEMBLY__ */
> #endif /* __ASM_BARRIER_H */
> --- a/arch/arm/include/asm/bitops.h
> +++ b/arch/arm/include/asm/bitops.h
> @@ -25,9 +25,7 @@
>
> #include <linux/compiler.h>
> #include <linux/irqflags.h>
> -
> -#define smp_mb__before_clear_bit() smp_mb()
> -#define smp_mb__after_clear_bit() smp_mb()
> +#include <asm/barrier.h>
>
> /*
> * These functions are the basis of our bit ops.
>
>
>
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