cpumask: add cpumask_any_and_but()

In some cases, it's useful to be able to select a random cpu from the
intersection of two masks, excluding a particular CPU.

For example, in some systems an uncore PMU is shared by a subset of
CPUs, and management of this PMU is assigned to some arbitrary CPU in
this set. Whenever the management CPU is hotplugged out, we wish to
migrate responsibility to another arbitrary CPU which is both in this
set and online.

Today we can use cpumask_any_and() to select an arbitrary CPU in the
intersection of two masks. We can also use cpumask_any_but() to select
any arbitrary cpu in a mask excluding, a particular CPU.

To do both, we either need to use a temporary cpumask, which is
wasteful, or use some lower-level cpumask helpers, which can be unclear.

This patch adds a new cpumask_any_and_but() to cater for these cases.

Signed-off-by: Mark Rutland <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rusty Russell <[email protected]>
Cc: [email protected]
Signed-off-by: Dawei Li <[email protected]>
Acked-by: Yury Norov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

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