Hi Paul,
Nice catch.
On 2025-01-09 11:37:06 +0000, Paul Barker wrote:
> When tx_max_frame_size was added to struct ravb_hw_info, no value was
> set in ravb_rzv2m_hw_info so the default value of zero was used.
>
> The maximum MTU is set by subtracting from tx_max_frame_size to allow
> space for headers and frame checksums. As ndev->max_mtu is unsigned,
> this subtraction wraps around leading to a ridiculously large positive
> value that is obviously incorrect.
>
> Before tx_max_frame_size was introduced, the maximum MTU was based on
> rx_max_frame_size. So, we can restore the correct maximum MTU by copying
> the rx_max_frame_size value into tx_max_frame_size for RZ/V2M.
>
> Fixes: 1d63864299ca ("net: ravb: Fix maximum TX frame size for GbEth devices")
> Signed-off-by: Paul Barker <paul.barker.ct@xxxxxxxxxxxxxx>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
> ---
> drivers/net/ethernet/renesas/ravb_main.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
> index ac0f093f647a..bc395294a32d 100644
> --- a/drivers/net/ethernet/renesas/ravb_main.c
> +++ b/drivers/net/ethernet/renesas/ravb_main.c
> @@ -2763,6 +2763,7 @@ static const struct ravb_hw_info ravb_rzv2m_hw_info = {
> .net_features = NETIF_F_RXCSUM,
> .stats_len = ARRAY_SIZE(ravb_gstrings_stats),
> .tccr_mask = TCCR_TSRQ0 | TCCR_TSRQ1 | TCCR_TSRQ2 | TCCR_TSRQ3,
> + .tx_max_frame_size = SZ_2K,
> .rx_max_frame_size = SZ_2K,
> .rx_buffer_size = SZ_2K +
> SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
>
> base-commit: 2d2d4f60ed266a8f340a721102d035252606980b
> --
> 2.39.5
>
--
Kind Regards,
Niklas Söderlund
