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

Reinette Chatre
2025-04-23T21:29:21Z

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.

> +{
> + unsigned int i;
> +
> + /* -1 is a legal arg here. */
> + if (cpu != -1)
> + cpumask_check(cpu);
> +
> + i = cpumask_first_andnot(mask1, mask2);
> + if (i != cpu)
> + return i;
> +
> + return cpumask_next_andnot(cpu, mask1, mask2);
> +}
> +
> /**
> * cpumask_nth - get the Nth cpu in a cpumask
> * @srcp: the cpumask pointer

Reinette