Re: [PATCH net-next v3 6/7] net: mctp: usblib: Add initial kunit tx tests

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi James,

On Wed, 14 Oct 2026 at 06:54, James Lee <james@codeconstruct.com.au> wrote:
> Add tests for the transmit path, where MCTP packets are handed to
> outgoing USB transfer data. Testing a spanning transfer that is expected
> to succeed, the failure paths when sends fail, and large sequential
> sends.
>
> Signed-off-by: James Lee <james@codeconstruct.com.au>
>
> ---
> v2:
> - Correct flex array reference
> - Simply return when mctp_usblib_test_tx_send() fails
> - Use skb_put_data() instead of manual assignment
> - Remember span parameter exists

Thanks for your patch, which is now commit 1e12f734afc10477 ("net:
mctp: usblib: Add initial kunit tx tests") upstream.

> --- a/drivers/net/mctp/mctp-usblib-test.c
> +++ b/drivers/net/mctp/mctp-usblib-test.c

> +
> +/* Test sending multiple packets in the same transfer, followed by one that
> + * spans multiple subsequent transfers.
> + */
> +static void mctp_usblib_test_tx_multi_push(struct kunit *test)
> +{
> +       struct mctp_usblib_test_ctx *ctx;
> +       size_t i, max_length, tx_length;
> +       struct mctp_usblib_tx_ops ops;
> +       u8 *buf, *flat_tx, *index;
> +       struct mctp_usblib_tx *tx;
> +       struct net_device *ndev;
> +       struct sk_buff *skb;
> +       const struct {
> +               size_t len;
> +               bool more;
> +       } sends[] = {
> +               { 1000, true  },
> +               {  500, false },
> +               { 5000, false },
> +       };
> +       int rc;
> +
> +       static_assert(!sends[ARRAY_SIZE(sends) - 1].more,
> +                     "The last push must claim there will be no more");

This fails with gcc-14 (the latest available in Ubuntu 24.04LTS)
and earlier:

drivers/net/mctp/mctp-usblib-test.c:819:23: error: expression in
static assertion is not constant
  819 |         static_assert(!sends[ARRAY_SIZE(sends) - 1].more,
      |                       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds