Re: [RFC bpf-next 6/7] selftests/bpf: extend xdp_metadata with devtx kfuncs

[Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx>]

On Mon, Jun 12, 2023 at 7:26 PM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote:
>
> Attach kfuncs that request and report TX timestamp via ringbuf.
> Confirm on the userspace side that the program has triggered
> and the timestamp is non-zero.
>
> Also make sure devtx_frame has a sensible pointers and data.
>
> Cc: netdev@xxxxxxxxxxxxxxx
> Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>

> +SEC("fentry/devtx_sb")
> +int BPF_PROG(devtx_sb, const struct devtx_frame *frame)
> +{
> +       int ret;
> +
> +       ret = verify_frame(frame);
> +       if (ret < 0)
> +               __sync_add_and_fetch(&pkts_fail_tx, 1);

intend to return in these error cases? in this and following patch

> +
> +       ret = bpf_devtx_sb_request_timestamp(frame);
> +       if (ret < 0)
> +               __sync_add_and_fetch(&pkts_fail_tx, 1);
> +
> +       return 0;
> +}
> +
> +SEC("fentry/devtx_cp")
> +int BPF_PROG(devtx_cp, const struct devtx_frame *frame)
> +{
> +       struct devtx_sample *sample;
> +       int ret;
> +
> +       ret = verify_frame(frame);
> +       if (ret < 0)
> +               __sync_add_and_fetch(&pkts_fail_tx, 1);
> +
> +       sample = bpf_ringbuf_reserve(&tx_compl_buf, sizeof(*sample), 0);
> +       if (!sample)
> +               return 0;

return non-zero?

> +
> +       sample->timestamp_retval = bpf_devtx_cp_timestamp(frame, &sample->timestamp);
> +
> +       bpf_ringbuf_submit(sample, 0);
> +
> +       return 0;
> +}