netxen: fix race in skb->len access

As soon as skb is given to hardware, TX completion can free skb under
us.
Therefore, we should update dev stats before kicking the device.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Amit Kumar Salecha <amit.salecha@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/netxen/netxen_nic_main.c

@@ -1965,11 +1965,11 @@ netxen_nic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
 
 	netxen_tso_check(netdev, tx_ring, first_desc, skb);
 
-	netxen_nic_update_cmd_producer(adapter, tx_ring);
-
 	adapter->stats.txbytes += skb->len;
 	adapter->stats.xmitcalled++;
 
+	netxen_nic_update_cmd_producer(adapter, tx_ring);
+
 	return NETDEV_TX_OK;
 
 drop_packet: