Re: [RFC][PATCH 01/31] locking: Flip arguments to atomic_fetch_or

[Will Deacon]

On Fri, Apr 22, 2016 at 11:04:14AM +0200, Peter Zijlstra wrote:
> All the atomic operations have their arguments the wrong way around;
> make atomic_fetch_or() consistent and flip them.
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> ---
>  include/linux/atomic.h   |    4 ++--
>  kernel/time/tick-sched.c |    4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)

Makes sense:

Acked-by: Will Deacon <will.deacon@xxxxxxx>

Will

> --- a/include/linux/atomic.h
> +++ b/include/linux/atomic.h
> @@ -560,11 +560,11 @@ static inline int atomic_dec_if_positive
>  
>  /**
>   * atomic_fetch_or - perform *p |= mask and return old value of *p
> - * @p: pointer to atomic_t
>   * @mask: mask to OR on the atomic_t
> + * @p: pointer to atomic_t
>   */
>  #ifndef atomic_fetch_or
> -static inline int atomic_fetch_or(atomic_t *p, int mask)
> +static inline int atomic_fetch_or(int mask, atomic_t *p)
>  {
>  	int old, val = atomic_read(p);
>  
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -262,7 +262,7 @@ static void tick_nohz_dep_set_all(atomic
>  {
>  	int prev;
>  
> -	prev = atomic_fetch_or(dep, BIT(bit));
> +	prev = atomic_fetch_or(BIT(bit), dep);
>  	if (!prev)
>  		tick_nohz_full_kick_all();
>  }
> @@ -292,7 +292,7 @@ void tick_nohz_dep_set_cpu(int cpu, enum
>  
>  	ts = per_cpu_ptr(&tick_cpu_sched, cpu);
>  
> -	prev = atomic_fetch_or(&ts->tick_dep_mask, BIT(bit));
> +	prev = atomic_fetch_or(BIT(bit), &ts->tick_dep_mask);
>  	if (!prev) {
>  		preempt_disable();
>  		/* Perf needs local kick that is NMI safe */
> 
>