Re: [PATCH bpf-next 00/17] Improve BPF syscall command documentation

Joe Stringer
2021-02-18T04:11:23Z

On Wed, Feb 17, 2021 at 5:55 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
> Joe Stringer <joe@wand.net.nz> writes:
> > Given the relative success of the process around bpf-helpers(7) to
> > encourage developers to document their user-facing changes, in this
> > patch series I explore applying this technique to bpf(2) as well.
> > Unfortunately, even with bpf(2) being so out-of-date, there is still a
> > lot of content to convert over. In particular, I've identified at least
> > the following aspects of the bpf syscall which could individually be
> > generated from separate documentation in the header:
> > * BPF syscall commands
> > * BPF map types
> > * BPF program types
> > * BPF attachment points
>
> Does this also include program subtypes (AKA expected_attach_type?)

I seem to have left my lawyerly "including, but not limited to..."
language at home today ;-) . Of course, I can add that to the list.

> > At this point I'd like to put this out for comments. In my mind, the
> > ideal eventuation of this work would be to extend kernel UAPI headers
> > such that each of the categories I had listed above (commands, maps,
> > progs, hooks) have dedicated documentation in the kernel tree, and that
> > developers must update the comments in the headers to document the APIs
> > prior to patch acceptance, and that we could auto-generate the latest
> > version of the bpf(2) manual pages based on a few static description
> > sections combined with the dynamically-generated output from the header.
>
> I like the approach, and I don't think it's too onerous to require
> updates to the documentation everywhere like we (as you note) already do
> for helpers.
>
> So with that, please feel free to add my enthusiastic:
>
> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>

Thanks Toke.