Re: [PATCH 1/3] sched_ext: Rename scx_cmask.nr_bits to nr_cids

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The struct field 'nr_bits' in 'struct scx_cmask' was renamed to 'nr_cids', but the function 'cmask_copy_from_kernel()' in 'tools/sched_ext/include/scx/cid.bpf.h' still references 'src->nr_bits' and 'dst->nr_bits'. This will cause a compilation error for BPF programs including this header.
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commit 10e6d97c74e4139adeb947156f1940e0b2848eb4
Author: Tejun Heo <tj@kernel.org>

sched_ext: Rename scx_cmask.nr_bits to nr_cids

This commit renames the nr_bits field in struct scx_cmask to nr_cids.
This aligns the naming with the sibling struct scx_cid_shard to provide
a consistent API for future cmask patches.

> diff --git a/kernel/sched/ext_types.h b/kernel/sched/ext_types.h
> index ebb8cdf906123..c6c4e3db73111 100644
> --- a/kernel/sched/ext_types.h
> +++ b/kernel/sched/ext_types.h
> @@ -82,21 +82,21 @@ struct scx_cid_topo {
>   */
>  struct scx_cmask {
>  	u32 base;
> -	u32 nr_bits;
> +	u32 nr_cids;
>  	DECLARE_FLEX_ARRAY(u64, bits);
>  };

Since the field is renamed to nr_cids here, does cmask_copy_from_kernel() in
tools/sched_ext/include/scx/cid.bpf.h also need to be updated?

It appears to still reference the old nr_bits field:

tools/sched_ext/include/scx/cid.bpf.h:cmask_copy_from_kernel() {
    ...
    if (bpf_probe_read_kernel(&nr_bits, sizeof(nr_bits), &src->nr_bits)) {
        scx_bpf_error("probe-read cmask->nr_bits failed");
        return;
    }

    if (nr_bits > dst->nr_bits) {
        scx_bpf_error("src cmask nr_bits=%u exceeds dst nr_bits=%u",
                      nr_bits, dst->nr_bits);
        return;
    }
    ...
}

Will this cause a compilation error for BPF programs including this header?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260517183614.1191534-1-tj@kernel.org?part=1