[xdp-hints] Re: [PATCH bpf-next V3 3/6] selftests/bpf: xdp_hw_metadata RX hash return code info

[Stanislav Fomichev <sdf@google.com>]

On Wed, Mar 22, 2023 at 9:09 AM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Wed, Mar 22, 2023 at 9:01 AM Jesper Dangaard Brouer
> <brouer@redhat.com> wrote:
> >
> > When driver developers add XDP-hints kfuncs for RX hash it is
> > practical to print the return code in bpf_printk trace pipe log.
> >
> > Print hash value as a hex value, both AF_XDP userspace and bpf_prog,
> > as this makes it easier to spot poor quality hashes.
> >
> > Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> > Acked-by: Stanislav Fomichev <sdf@google.com>
> > ---
> >  .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |    9 ++++++---
> >  tools/testing/selftests/bpf/xdp_hw_metadata.c      |    5 ++++-
> >  2 files changed, 10 insertions(+), 4 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> > index 40c17adbf483..ce07010e4d48 100644
> > --- a/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> > +++ b/tools/testing/selftests/bpf/progs/xdp_hw_metadata.c
> > @@ -77,10 +77,13 @@ int rx(struct xdp_md *ctx)
> >                 meta->rx_timestamp = 0; /* Used by AF_XDP as not avail signal */
> >         }
> >
> > -       if (!bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash))
> > -               bpf_printk("populated rx_hash with %u", meta->rx_hash);
> > -       else
> > +       ret = bpf_xdp_metadata_rx_hash(ctx, &meta->rx_hash);
> > +       if (ret >= 0) {
> > +               bpf_printk("populated rx_hash with 0x%08X", meta->rx_hash);
> > +       } else {
> > +               bpf_printk("rx_hash not-avail errno:%d", ret);
> >                 meta->rx_hash = 0; /* Used by AF_XDP as not avail signal */
> > +       }
>
> Just noticed this mess of printks.
> Please remove them all. selftests should not have them.

See my reply in the v2.