Re: [PATCH 01/14] net: ethernet: mtk_eth_soc: account for vlan in rx header length

Vladimir Oltean
2022-11-07T20:56:23Z

On Mon, Nov 07, 2022 at 07:54:39PM +0100, Felix Fietkau wrote:
> This may be needed for correct MTU settings on devices using DSA
>
> Signed-off-by: Felix Fietkau <nbd@nbd.name>
> ---
> drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> index 589f27ddc401..dcf2a0d5da33 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
> @@ -29,7 +29,7 @@
> #define MTK_TX_DMA_BUF_LEN_V2 0xffff
> #define MTK_DMA_SIZE 512
> #define MTK_MAC_COUNT 2
> -#define MTK_RX_ETH_HLEN (ETH_HLEN + ETH_FCS_LEN)
> +#define MTK_RX_ETH_HLEN (VLAN_ETH_HLEN + ETH_HLEN + ETH_FCS_LEN)

Commit title says account for VLAN (VLAN_HLEN, 4 bytes), code says add
VLAN_ETH_HLEN (18) more bytes.

Also, why is DSA mentioned in the commit message? Is accounting for VLAN
hlen not needed if DSA is not used? Why?

> #define MTK_RX_HLEN (NET_SKB_PAD + MTK_RX_ETH_HLEN + NET_IP_ALIGN)
> #define MTK_DMA_DUMMY_DESC 0xffffffff
> #define MTK_DEFAULT_MSG_ENABLE (NETIF_MSG_DRV | \
> --
> 2.38.1
>