i40e: do TSO only if CHECKSUM_PARTIAL is set

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

Don't bother trying to set up a TSO if the skb->ip_summed is not
set to CHECKSUM_PARTIAL.

Change-ID: I6495b3568e404907a2965b48cf3e2effa7c9ab55
Signed-off-by: Shannon Nelson <shannon.nelson@intel.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 e9f6563d)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

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

@@ -2222,6 +2222,9 @@ static int i40e_tso(struct i40e_ring *tx_ring, struct sk_buff *skb,
 	u32 l4len;
 	int err;
 
+	if (skb->ip_summed != CHECKSUM_PARTIAL)
+		return 0;
+
 	if (!skb_is_gso(skb))
 		return 0;
 

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

@@ -1472,6 +1472,9 @@ static int i40e_tso(struct i40e_ring *tx_ring, struct sk_buff *skb,
 	u32 l4len;
 	int err;
 
+	if (skb->ip_summed != CHECKSUM_PARTIAL)
+		return 0;
+
 	if (!skb_is_gso(skb))
 		return 0;