netxen: hold tx lock while sending firmware commands

Some firmware commands like mac address addition/deletion are sent
on the transmit ring. So need to hold the tx lock before touching
tx producer/consumer indices.
Signed-off-by: NDhananjay Phadke <dhananjay@netxen.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/netxen/netxen_nic_hw.c

@@ -503,6 +503,8 @@ netxen_send_cmd_descs(struct netxen_adapter *adapter,
 
 	i = 0;
 
+	netif_tx_lock_bh(adapter->netdev);
+
 	producer = adapter->cmd_producer;
 	do {
 		cmd_desc = &cmd_desc_arr[i];
@@ -527,6 +529,8 @@ netxen_send_cmd_descs(struct netxen_adapter *adapter,
 
 	netxen_nic_update_cmd_producer(adapter, adapter->cmd_producer);
 
+	netif_tx_unlock_bh(adapter->netdev);
+
 	return 0;
 }