[PATCH] atomic: add *_dec_not_zero

[Benjamin Herrenschmidt]

On Tue, 2011-05-03 at 23:30 +0200, Sven Eckelmann wrote:
> Introduce an *_dec_not_zero operation.  Make this a special case of
> *_add_unless because batman-adv uses atomic_dec_not_zero in different
> places like re-broadcast queue or aggregation queue management. There
> are other non-final patches which may also want to use this macro.

For arch/powerpc:

Acked-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>

(Sorry for catching up late)

Cheers,
Ben.

> diff --git a/arch/powerpc/include/asm/atomic.h b/arch/powerpc/include/asm/atomic.h
> index b8f152e..906f49a 100644
> --- a/arch/powerpc/include/asm/atomic.h
> +++ b/arch/powerpc/include/asm/atomic.h
> @@ -213,6 +213,7 @@ static __inline__ int atomic_add_unless(atomic_t *v, int a, int u)
>  }
>  
>  #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
> +#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
>  
>  #define atomic_sub_and_test(a, v)	(atomic_sub_return((a), (v)) == 0)
>  #define atomic_dec_and_test(v)		(atomic_dec_return((v)) == 0)
> @@ -469,6 +470,7 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
>  }
>  
>  #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
> +#define atomic64_dec_not_zero(v) atomic64_add_unless((v), -1, 0)
>  
>  #else  /* __powerpc64__ */
>  #include <asm-generic/atomic64.h>
> diff --git a/arch/powerpc/include/asm/local.h b/arch/powerpc/include/asm/local.h
> index c2410af..3d4c58a 100644
> --- a/arch/powerpc/include/asm/local.h
> +++ b/arch/powerpc/include/asm/local.h
> @@ -134,6 +134,7 @@ static __inline__ int local_add_unless(local_t *l, long a, long u)
>  }
>  
>  #define local_inc_not_zero(l) local_add_unless((l), 1, 0)
> +#define local_dec_not_zero(l) local_add_unless((l), -1, 0)
>  
>  #define local_sub_and_test(a, l)	(local_sub_return((a), (l)) == 0)
>  #define local_dec_and_test(l)		(local_dec_return((l)) == 0)