sunvnet: remove extra rcu_read_unlocks

The RCU read lock is grabbed first thing in sunvnet_start_xmit_common()
so it always needs to be released.  This removes the conditional release
in the dropped packet error path and removes a couple of superfluous
calls in the middle of the code.
Reported-by: NBijan Mottahedeh <bijan.mottahedeh@oracle.com>
Signed-off-by: NShannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/sun/sunvnet_common.c

@@ -1253,10 +1253,8 @@ int sunvnet_start_xmit_common(struct sk_buff *skb, struct net_device *dev,
 
 	rcu_read_lock();
 	port = vnet_tx_port(skb, dev);
-	if (unlikely(!port)) {
-		rcu_read_unlock();
+	if (unlikely(!port))
 		goto out_dropped;
-	}
 
 	if (skb_is_gso(skb) && skb->len > port->tsolen) {
 		err = vnet_handle_offloads(port, skb, vnet_tx_port);
@@ -1281,7 +1279,6 @@ int sunvnet_start_xmit_common(struct sk_buff *skb, struct net_device *dev,
 			fl4.saddr = ip_hdr(skb)->saddr;
 
 			rt = ip_route_output_key(dev_net(dev), &fl4);
-			rcu_read_unlock();
 			if (!IS_ERR(rt)) {
 				skb_dst_set(skb, &rt->dst);
 				icmp_send(skb, ICMP_DEST_UNREACH,
@@ -1441,8 +1438,7 @@ int sunvnet_start_xmit_common(struct sk_buff *skb, struct net_device *dev,
 				jiffies + VNET_CLEAN_TIMEOUT);
 	else if (port)
 		del_timer(&port->clean_timer);
-	if (port)
-		rcu_read_unlock();
+	rcu_read_unlock();
 	if (skb)
 		dev_kfree_skb(skb);
 	vnet_free_skbs(freeskbs);