tipc: ensure that first packets on link are sent in order

In some link establishment scenarios we see that packet #2 may be sent
out before packet #1, forcing the receiver to demand retransmission of
the missing packet. This is harmless, but may cause confusion among
people tracing the packet flow.

Since this is extremely easy to fix, we do so by adding en extra send
call to the bearer immediately after the link has come up.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/node.c

@@ -581,8 +581,12 @@ static void __tipc_node_link_up(struct tipc_node *n, int bearer_id,
 static void tipc_node_link_up(struct tipc_node *n, int bearer_id,
 			      struct sk_buff_head *xmitq)
 {
+	struct tipc_media_addr *maddr;
+
 	tipc_node_write_lock(n);
 	__tipc_node_link_up(n, bearer_id, xmitq);
+	maddr = &n->links[bearer_id].maddr;
+	tipc_bearer_xmit(n->net, bearer_id, xmitq, maddr);
 	tipc_node_write_unlock(n);
 }