iavf: add support for UDP Segmentation Offload

Add code to support UDP segmentation offload (USO) for
hardware that supports it.

Suggested-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Brett Creeley <brett.creeley@intel.com>
Tested-by: Konrad Jankowski <konrad0.jankowski@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/iavf/iavf_main.c

@@ -3542,6 +3542,8 @@ int iavf_process_config(struct iavf_adapter *adapter)
 	/* Enable cloud filter if ADQ is supported */
 	if (vfres->vf_cap_flags & VIRTCHNL_VF_OFFLOAD_ADQ)
 		hw_features |= NETIF_F_HW_TC;
+	if (vfres->vf_cap_flags & VIRTCHNL_VF_OFFLOAD_USO)
+		hw_features |= NETIF_F_GSO_UDP_L4;
 
 	netdev->hw_features |= hw_features;
 

drivers/net/ethernet/intel/iavf/iavf_txrx.c

@@ -1905,13 +1905,20 @@ static int iavf_tso(struct iavf_tx_buffer *first, u8 *hdr_len,
 
 	/* determine offset of inner transport header */
 	l4_offset = l4.hdr - skb->data;
-
 	/* 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 */
+	if (skb_shinfo(skb)->gso_type & SKB_GSO_UDP_L4) {
-	*hdr_len = (l4.tcp->doff * 4) + l4_offset;
+		csum_replace_by_diff(&l4.udp->check,
+				     (__force __wsum)htonl(paylen));
+		/* compute length of UDP segmentation header */
+		*hdr_len = (u8)sizeof(l4.udp) + l4_offset;
+	} else {
+		csum_replace_by_diff(&l4.tcp->check,
+				     (__force __wsum)htonl(paylen));
+		/* compute length of TCP segmentation header */
+		*hdr_len = (u8)((l4.tcp->doff * 4) + l4_offset);
+	}
 
 	/* pull values out of skb_shinfo */
 	gso_size = skb_shinfo(skb)->gso_size;

drivers/net/ethernet/intel/iavf/iavf_virtchnl.c

@@ -140,6 +140,7 @@ int iavf_send_vf_config_msg(struct iavf_adapter *adapter)
 	       VIRTCHNL_VF_OFFLOAD_ENCAP_CSUM |
 	       VIRTCHNL_VF_OFFLOAD_REQ_QUEUES |
 	       VIRTCHNL_VF_OFFLOAD_ADQ |
+	       VIRTCHNL_VF_OFFLOAD_USO |
 	       VIRTCHNL_VF_OFFLOAD_FDIR_PF |
 	       VIRTCHNL_VF_CAP_ADV_LINK_SPEED;