Re: [PATCHv2 bpf-next 13/15] selftests/bpf: Test syscall command parsing

[Joe Stringer <joe@cilium.io>]

On Wed, Mar 3, 2021 at 2:23 PM Yonghong Song <yhs@fb.com> wrote:
>
>
>
> On 3/2/21 9:19 AM, Joe Stringer wrote:
> > Add building of the bpf(2) syscall commands documentation as part of the
> > docs building step in the build. This allows us to pick up on potential
> > parse errors from the docs generator script as part of selftests.
> >
> > The generated manual pages here are not intended for distribution, they
> > are just a fragment that can be integrated into the other static text of
> > bpf(2) to form the full manual page.
>
> I tried and the generated bpf(2) man page looks like:
>
> BPF(2)
>
>                           BPF(2)
>
> NAME
>         bpf - Perform a command on an extended BPF object
>
> COMMANDS
>         BPF_MAP_CREATE
>
>                Description
>                       Create  a map and return a file descriptor that
> refers to the map. The close-on-exec file descriptor flag (see fcntl(2))
> is automatically enabled for the
>                       new file descriptor.
>
>                       Applying close(2) to the file descriptor returned
> by BPF_MAP_CREATE will delete the map (but see NOTES).
>
>                Return A new file descriptor (a nonnegative integer), or
> -1 if an error occurred (in which case, errno is set appropriately).
>
>         BPF_MAP_LOOKUP_ELEM
> ...
>         BPF_PROG_BIND_MAP
>
>                Description
>                       Bind a map to the lifetime of an eBPF program.
>
>                       The map identified by map_fd is bound to the
> program identified by prog_fd and only released when prog_fd is
> released. This may be used  in  cases  where
>                       metadata  should  be  associated  with  a  program
>   which otherwise does not contain any references to the map (for
> example, embedded in the eBPF program
>                       instructions).
>
>                Return Returns zero on success. On error, -1 is returned
> and errno is set appropriately.
>
>
> Yes, this needs to be integrated into the real man page. But this is
> already great so people can see latest bpf latest features without
> going to the source code. Thanks!

:party-parrot:

Yeah I think the step around integrating into the real man page is an
area that folks may have opinions on and I'm CC'ing Michael here in
particular, but ultimately that manual is currently managed in the
upstream manpages tree so nothing actionable from this series,
absolute simplest is for someone (is that me?) to just package this
hunk up and submit it to the upstream tree every once in a while.
Slightly more elaborate would involve integrating the static text with
this generated text somewhere (either kernel tree or manpages tree)
and have someone run a cron job to generate & submit the changes.
Could be another option, these are the obvious ones that come to mind.

> >
> > Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
> > Reviewed-by: Quentin Monnet <quentin@isovalent.com>
> > Signed-off-by: Joe Stringer <joe@cilium.io>
>
> Acked-by: Yonghong Song <yhs@fb.com>