Re: [PATCHv3 09/18] atomics/alpha: define atomic64_fetch_add_unless()

[Will Deacon]

On Mon, Jun 18, 2018 at 11:19:10AM +0100, Mark Rutland wrote:
> As a step towards unifying the atomic/atomic64/atomic_long APIs, this
> patch converts the arch/alpha implementation of atomic64_add_unless() into
> an implementation of atomic64_fetch_add_unless().
> 
> A wrapper in <linux/atomic.h> will build atomic_add_unless() atop of
> this, provided it is given a preprocessor definition.
> 
> No functional change is intended as a result of this patch.
> 
> Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> Cc: Boqun Feng <boqun.feng@xxxxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: Richard Henderson <rth@xxxxxxxxxxx>
> Cc: Ivan Kokshaysky <ink@xxxxxxxxxxxxxxxxxxxx>
> Cc: Matt Turner <mattst88@xxxxxxxxx>
> ---
>  arch/alpha/include/asm/atomic.h | 23 ++++++++++++-----------
>  1 file changed, 12 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h
> index 4a800a3424a3..dcb7bbeeae02 100644
> --- a/arch/alpha/include/asm/atomic.h
> +++ b/arch/alpha/include/asm/atomic.h
> @@ -238,35 +238,36 @@ static __inline__ int atomic_fetch_add_unless(atomic_t *v, int a, int u)
>  #define atomic_fetch_add_unless atomic_fetch_add_unless
>  
>  /**
> - * atomic64_add_unless - add unless the number is a given value
> + * atomic64_fetch_add_unless - add unless the number is a given value
>   * @v: pointer of type atomic64_t
>   * @a: the amount to add to v...
>   * @u: ...unless v is equal to u.
>   *
>   * Atomically adds @a to @v, so long as it was not @u.
> - * Returns true iff @v was not @u.
> + * Returns the old value of @v.
>   */
> -static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
> +static __inline__ int atomic64_fetch_add_unless(atomic64_t *v, long a, long u)

Don't you want a 64-bit return type (e.g. long) here?

Will