Re: [PATCHv2] atomic: add *_dec_not_zero

[Heiko Carstens <heiko.carstens@de.ibm.com>]

On Wed, May 18, 2011 at 09:49:54PM +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.
[...]
> ---
> This is actually the same patch as before, but I am still waiting for
> some (N)Acks for ia64, m32r, s390, sh and generic.
[...]
> diff --git a/arch/s390/include/asm/atomic.h b/arch/s390/include/asm/atomic.h
> index d9db138..09972c3 100644
> --- a/arch/s390/include/asm/atomic.h
> +++ b/arch/s390/include/asm/atomic.h
> @@ -109,6 +109,7 @@ 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)
> 
>  #undef __CS_LOOP
> 
> @@ -326,6 +327,7 @@ static inline long long atomic64_dec_if_positive(atomic64_t *v)
>  #define atomic64_dec_return(_v)		atomic64_sub_return(1, _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 atomic64_dec_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()

Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>