Re: [PATCH v2 2/2] net: dsa: tag_ksz: dont let the hardware process the layer 4 checksum

[Vladimir Oltean]

On Wed, Jul 21, 2021 at 11:56:42PM +0200, Lino Sanfilippo wrote:
> If the checksum calculation is offloaded to the network device (e.g due to
> NETIF_F_HW_CSUM inherited from the DSA master device), the calculated
> layer 4 checksum is incorrect. This is since the DSA tag which is placed
> after the layer 4 data is considered as being part of the daa and thus
> errorneously included into the checksum calculation.
> To avoid this, always calculate the layer 4 checksum in software.
> 
> Signed-off-by: Lino Sanfilippo <LinoSanfilippo@xxxxxx>
> ---

Fixes: 8b8010fb7876 ("dsa: add support for Microchip KSZ tail tagging")
Reviewed-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>