Re: [PATCH v4 2/7] cpumask: Introduce for_each_cpu_andnot()

[Valentin Schneider]

On 25/09/22 08:23, Yury Norov wrote:
> On Fri, Sep 23, 2022 at 04:55:37PM +0100, Valentin Schneider wrote:
>> +/**
>> + * for_each_cpu_andnot - iterate over every cpu present in one mask, excluding
>> + *			 those present in another.
>> + * @cpu: the (optionally unsigned) integer iterator
>> + * @mask1: the first cpumask pointer
>> + * @mask2: the second cpumask pointer
>> + *
>> + * This saves a temporary CPU mask in many places.  It is equivalent to:
>> + *	struct cpumask tmp;
>> + *	cpumask_andnot(&tmp, &mask1, &mask2);
>> + *	for_each_cpu(cpu, &tmp)
>> + *		...
>> + *
>> + * After the loop, cpu is >= nr_cpu_ids.
>> + */
>> +#define for_each_cpu_andnot(cpu, mask1, mask2)				\
>> +	for ((cpu) = -1;						\
>> +		(cpu) = cpumask_next_andnot((cpu), (mask1), (mask2)),	\
>> +		(cpu) < nr_cpu_ids;)
>
> This would raise cpumaks_check() warning at the very last iteration.
> Because cpu is initialized insize the loop, you don't need to check it
> at all. You can do it like this:
>
>  #define for_each_cpu_andnot(cpu, mask1, mask2)				\
>          for_each_andnot_bit(...)
>
> Check this series for details (and please review).
> https://lore.kernel.org/all/20220919210559.1509179-8-yury.norov@xxxxxxxxx/T/
>

Thanks, I'll have a look.

> Thanks,
> Yury