Re: [PATCH 0/2] rust: cpumask: Bindings for core cpumasks and cpumask iterators

John Hubbard
2025-11-06T00:19:51Z

On 11/5/25 3:16 PM, Mitchell Levy wrote:
> The kernel provides a number of very useful CPU masks from the C side,
> including CPU masks for possible and online CPUs. In particular, these
> are very useful when some operation must be done on each CPU (either
> each possible CPU or each online CPU, etc). Therefore, it seems to make
> sense to add both of these functionalities at once.
>
> Signed-off-by: Mitchell Levy <levymitchell0@gmail.com>
> ---
> These patches originated as part of my work on a Rust per-CPU API [1].
> Boqun suggested to me that these may make sense to merge separately, and
> it does seem like these might be useful beyond the per-CPU work.
>
> [1]: https://lore.kernel.org/rust-for-linux/20251105-rust-percpu-v4-0-984b1470adcb@gmail.com/

Even though you are trying to get these two patches merged separately,
I think it's best (for reviewers) if you post a patchset that shows
these things being used. Otherwise it is potentially too unmoored from
reality, and hard to be sure that it's exactly right from a caller's
point of view.

In this case, just posting that 9-patch series might work, and just
say in the cover letter that patches 3 through 9 are not ready for
merging.

Something like that.

I realize that Rust for Linux is being built from scratch right
now, but including calling code in a patchset is a really valuable
kernel convention that helps validate the code.

I say this for the benefit of others who may be reading. :)

thanks,
--
John Hubbard