Re: [PATCH v2 1/6] cpumask: introduce for_each_cpu_and_from()

[Yury Norov <yury.norov@gmail.com>]

On Thu, Dec 07, 2023 at 01:41:56PM -0800, Andrew Morton wrote:
> On Thu,  7 Dec 2023 12:38:55 -0800 Yury Norov <yury.norov@gmail.com> wrote:
> 
> > Similarly to for_each_cpu_and(), introduce a for_each_cpu_and_from(),
> > which is handy when it's needed to traverse 2 cpumasks or bitmaps,
> > starting from a given position.
> 
> A naming question:
> 
> > --- a/include/linux/cpumask.h
> > +++ b/include/linux/cpumask.h
> > @@ -332,6 +332,17 @@ unsigned int __pure cpumask_next_wrap(int n, const struct cpumask *mask, int sta
> >  #define for_each_cpu_and(cpu, mask1, mask2)				\
> >  	for_each_and_bit(cpu, cpumask_bits(mask1), cpumask_bits(mask2), small_cpumask_bits)
> >  
> > +/**
> > + * for_each_cpu_and_from - iterate over every cpu in both masks starting from a given cpu
> > + * @cpu: the (optionally unsigned) integer iterator
> > + * @mask1: the first cpumask pointer
> > + * @mask2: the second cpumask pointer
> > + *
> > + * After the loop, cpu is >= nr_cpu_ids.
> > + */
> > +#define for_each_cpu_and_from(cpu, mask1, mask2)				\
> > +	for_each_and_bit_from(cpu, cpumask_bits(mask1), cpumask_bits(mask2), small_cpumask_bits)
> 
> Shouldn't this be for_each_and_cpu_from()?  That seems more consistent
> and makes a little more sense given what the iterator does.

Maybe it should... But we already have some iterators with this type
of naming: for_each_cpu_and, for_each_cpu_andnot, for_each_cpu_or.

This naming style goes quite long back in the history. Corresponding
bitmap iterators have better naming although...