tipc: eliminate delayed link deletion at link failover

When a bearer is disabled manually, all its links have to be reset
and deleted. However, if there is a remaining, parallel link ready
to take over a deleted link's traffic, we currently delay the delete
of the removed link until the failover procedure is finished. This
is because the remaining link needs to access state from the reset
link, such as the last received packet number, and any partially
reassembled buffer, in order to perform a successful failover.

In this commit, we do instead move the state data over to the new
link, so that it can fulfill the procedure autonomously, without
accessing any data on the old link. This means that we can now
proceed and delete all pertaining links immediately when a bearer
is disabled. This saves us from some unnecessary complexity in such
situations.

We also choose to change the confusing definitions CHANGEOVER_PROTOCOL,
ORIGINAL_MSG and DUPLICATE_MSG to the more descriptive TUNNEL_PROTOCOL,
FAILOVER_MSG and SYNCH_MSG respectively.

Reviewed-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>

1 files changed, 6 insertions, 7 deletions

diff --git a/net/tipc/node.c b/net/tipc/node.c
index 3e4f04897c03..f3d522c2881a 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -394,18 +394,17 @@ static void node_lost_contact(struct tipc_node *n_ptr)
 		n_ptr->bclink.recv_permitted = false;
 	}
 
-	/* Abort link changeover */
+	/* Abort any ongoing link failover */
 	for (i = 0; i < MAX_BEARERS; i++) {
 		struct tipc_link *l_ptr = n_ptr->links[i];
 		if (!l_ptr)
 			continue;
-		l_ptr->reset_checkpoint = l_ptr->next_in_no;
-		l_ptr->exp_msg_count = 0;
+		l_ptr->flags &= ~LINK_FAILINGOVER;
+		l_ptr->failover_checkpt = 0;
+		l_ptr->failover_pkts = 0;
+		kfree_skb(l_ptr->failover_skb);
+		l_ptr->failover_skb = NULL;
 		tipc_link_reset_fragments(l_ptr);
-
-		/* Link marked for deletion after failover? => do it now */
-		if (l_ptr->flags & LINK_STOPPED)
-			tipc_link_delete(l_ptr);
 	}
 
 	n_ptr->action_flags &= ~TIPC_WAIT_OWN_LINKS_DOWN;