[Intel-wired-lan] [PATCH v3 3/3] i40e: Add UDP segmentation offload support

[Samudrala, Sridhar]

On 10/11/2019 9:53 AM, Josh Hunt wrote:
> Based on a series from Alexander Duyck this change adds UDP segmentation
> offload support to the i40e driver.
> 
> CC: Alexander Duyck <alexander.h.duyck at intel.com>
> CC: Willem de Bruijn <willemb at google.com>
> Signed-off-by: Josh Hunt <johunt at akamai.com>
> ---
>   drivers/net/ethernet/intel/i40e/i40e_main.c |  1 +
>   drivers/net/ethernet/intel/i40e/i40e_txrx.c | 12 +++++++++---
>   2 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
> index 6031223eafab..56f8c52cbba1 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> @@ -12911,6 +12911,7 @@ static int i40e_config_netdev(struct i40e_vsi *vsi)
>   			  NETIF_F_GSO_IPXIP6		|
>   			  NETIF_F_GSO_UDP_TUNNEL	|
>   			  NETIF_F_GSO_UDP_TUNNEL_CSUM	|
> +			  NETIF_F_GSO_UDP_L4		|
>   			  NETIF_F_SCTP_CRC		|
>   			  NETIF_F_RXHASH		|
>   			  NETIF_F_RXCSUM		|
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> index e3f29dc8b290..b8496037ef7f 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
> @@ -2960,10 +2960,16 @@ static int i40e_tso(struct i40e_tx_buffer *first, u8 *hdr_len,
>   
>   	/* remove payload length from inner checksum */
>   	paylen = skb->len - l4_offset;
> -	csum_replace_by_diff(&l4.tcp->check, (__force __wsum)htonl(paylen));
>   
> -	/* compute length of segmentation header */
> -	*hdr_len = (l4.tcp->doff * 4) + l4_offset;
> +	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
> +		csum_replace_by_diff(&l4.udp->check, (__force __wsum)htonl(paylen));
> +		/* compute length of segmentation header */
> +		*hdr_len = sizeof(*l4.udp) + l4_offset;
> +	} else {
> +		csum_replace_by_diff(&l4.tcp->check, (__force __wsum)htonl(paylen));
> +		/* compute length of segmentation header */
> +		*hdr_len = (l4.tcp->doff * 4) + l4_offset;
> +	}

Is it guaranteed that gso_type can be either UDP or TCP only if we reach 
here? Don't we need to handle the case where it is neither and return 
from this function?

>   
>   	/* pull values out of skb_shinfo */
>   	gso_size = skb_shinfo(skb)->gso_size;
>