i40e/i40evf: Move Tx checksum closer to TSO

BugLink: http://bugs.launchpad.net/bugs/1547674

On all of the other Intel drivers we place checksum close to TSO as they
have a significant amount in common and it can help to reduce the decision
tree for how to handle the frame as the first check in TSO is to see if
checksumming is offloaded, and if it is not we can skip _BOTH_ TSO and Tx
checksum offload based on a single check.
Signed-off-by: Alexander Duyck <aduyck@mirantis.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from net-next commit 3bc67973)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -2930,6 +2930,12 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb,
 	else if (tso)
 		tx_flags |= I40E_TX_FLAGS_TSO;
 
+	/* Always offload the checksum, since it's in the data descriptor */
+	tso = i40e_tx_enable_csum(skb, &tx_flags, &td_cmd, &td_offset,
+				  tx_ring, &cd_tunneling);
+	if (tso < 0)
+		goto out_drop;
+
 	tsyn = i40e_tsyn(tx_ring, skb, tx_flags, &cd_type_cmd_tso_mss);
 
 	if (tsyn)
@@ -2940,12 +2946,6 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb,
 	/* always enable CRC insertion offload */
 	td_cmd |= I40E_TX_DESC_CMD_ICRC;
 
-	/* Always offload the checksum, since it's in the data descriptor */
-	tso = i40e_tx_enable_csum(skb, &tx_flags, &td_cmd, &td_offset,
-				  tx_ring, &cd_tunneling);
-	if (tso < 0)
-		goto out_drop;
-
 	i40e_create_tx_ctx(tx_ring, cd_type_cmd_tso_mss,
 			   cd_tunneling, cd_l2tag2);
 

drivers/net/ethernet/intel/i40evf/i40e_txrx.c

@@ -2149,17 +2149,17 @@ static netdev_tx_t i40e_xmit_frame_ring(struct sk_buff *skb,
 	else if (tso)
 		tx_flags |= I40E_TX_FLAGS_TSO;
 
-	skb_tx_timestamp(skb);
-
-	/* always enable CRC insertion offload */
-	td_cmd |= I40E_TX_DESC_CMD_ICRC;
-
 	/* Always offload the checksum, since it's in the data descriptor */
 	tso = i40e_tx_enable_csum(skb, &tx_flags, &td_cmd, &td_offset,
 				  tx_ring, &cd_tunneling);
 	if (tso < 0)
 		goto out_drop;
 
+	skb_tx_timestamp(skb);
+
+	/* always enable CRC insertion offload */
+	td_cmd |= I40E_TX_DESC_CMD_ICRC;
+
 	i40e_create_tx_ctx(tx_ring, cd_type_cmd_tso_mss,
 			   cd_tunneling, cd_l2tag2);