[TCP]: Optimize check in port-allocation code.

Signed-off-by: NFolkert van Heusden <folkert@vanheusden.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp_ipv4.c

@@ -222,10 +222,13 @@ static int tcp_v4_get_port(struct sock *sk, unsigned short snum)
 		int rover;
 
 		spin_lock(&tcp_portalloc_lock);
+		if (tcp_port_rover < low)
+			rover = low;
+		else
 			rover = tcp_port_rover;
 		do {
 			rover++;
-			if (rover < low || rover > high)
+			if (rover > high)
 				rover = low;
 			head = &tcp_bhash[tcp_bhashfn(rover)];
 			spin_lock(&head->lock);