Re: [PATCH 3/4] cpumask: add cpumask_{first,next}_andnot() API

Yury Norov
2025-04-24T02:59:02Z

On Wed, Apr 23, 2025 at 02:28:38PM -0700, Reinette Chatre wrote:
> Hi Yury,
>
> On 4/7/25 8:38 AM, Yury Norov wrote:
>
> ...
>
> > @@ -284,6 +297,25 @@ unsigned int cpumask_next_and(int n, const struct cpumask *src1p,
> > small_cpumask_bits, n + 1);
> > }
> >
> > +/**
> > + * cpumask_next_andnot - get the next cpu in *src1p & ~*src2p
> > + * @n: the cpu prior to the place to search (i.e. return will be > @n)
> > + * @src1p: the first cpumask pointer
> > + * @src2p: the second cpumask pointer
> > + *
> > + * Return: >= nr_cpu_ids if no further cpus set in both.
> > + */
> > +static __always_inline
> > +unsigned int cpumask_next_andnot(int n, const struct cpumask *src1p,
> > + const struct cpumask *src2p)
>
> Looks like the custom followed here is to name parameter that can have
> -1 as value "n" and let it have type "int". Should this also apply to
> cpumask_andnot_any_but(), cpumask_any_but(), and cpumask_any_and_but()
> modified/introduced in this series?
>
> > +{
> > + /* -1 is a legal arg here. */
> > + if (n != -1)
> > + cpumask_check(n);
> > + return find_next_andnot_bit(cpumask_bits(src1p), cpumask_bits(src2p),
> > + small_cpumask_bits, n + 1);
> > +}
> > +
> > /**
> > * cpumask_next_and_wrap - get the next cpu in *src1p & *src2p, starting from
> > * @n+1. If nothing found, wrap around and start from
> > @@ -458,6 +490,33 @@ unsigned int cpumask_any_and_but(const struct cpumask *mask1,
> > return cpumask_next_and(cpu, mask1, mask2);
> > }
> >
> > +/**
> > + * cpumask_andnot_any_but - pick an arbitrary cpu from *mask1 & ~*mask2, but not this one.
> > + * @mask1: the first input cpumask
> > + * @mask2: the second input cpumask
> > + * @cpu: the cpu to ignore
> > + *
> > + * If @cpu == -1, the function returns the first matching cpu.
> > + * Returns >= nr_cpu_ids if no cpus set.
> > + */
> > +static __always_inline
> > +unsigned int cpumask_andnot_any_but(const struct cpumask *mask1,
> > + const struct cpumask *mask2,
> > + unsigned int cpu)
>
> Since -1 is legal argument I expect "cpu" to be int.

Yes, you're right. I overlooked this. Will fix in v2