tipc: apply bearer link tolerance on running links

Currently, the default link tolerance set in struct tipc_bearer only
has effect on links going up after that moment. I.e., a user has to
reset all the node's links across that bearer to have the new value
applied. This is too limiting and disturbing on a running cluster to
be useful.

We now change this so that also already existing links are updated
dynamically, without any need for a reset, when the bearer value is
changed. We leverage the already existing per-link functionality
for this to achieve the wanted effect.
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/bearer.c

@@ -946,11 +946,11 @@ int tipc_nl_bearer_add(struct sk_buff *skb, struct genl_info *info)
 
 int tipc_nl_bearer_set(struct sk_buff *skb, struct genl_info *info)
 {
-	int err;
-	char *name;
 	struct tipc_bearer *b;
 	struct nlattr *attrs[TIPC_NLA_BEARER_MAX + 1];
 	struct net *net = sock_net(skb->sk);
+	char *name;
+	int err;
 
 	if (!info->attrs[TIPC_NLA_BEARER])
 		return -EINVAL;
@@ -982,8 +982,10 @@ int tipc_nl_bearer_set(struct sk_buff *skb, struct genl_info *info)
 			return err;
 		}
 
-		if (props[TIPC_NLA_PROP_TOL])
+		if (props[TIPC_NLA_PROP_TOL]) {
 			b->tolerance = nla_get_u32(props[TIPC_NLA_PROP_TOL]);
+			tipc_node_apply_tolerance(net, b);
+		}
 		if (props[TIPC_NLA_PROP_PRIO])
 			b->priority = nla_get_u32(props[TIPC_NLA_PROP_PRIO]);
 		if (props[TIPC_NLA_PROP_WIN])

net/tipc/link.c

@@ -2126,7 +2126,8 @@ void tipc_link_set_tolerance(struct tipc_link *l, u32 tol,
 			     struct sk_buff_head *xmitq)
 {
 	l->tolerance = tol;
-	tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
+	if (link_is_up(l))
+		tipc_link_build_proto_msg(l, STATE_MSG, 0, 0, 0, tol, 0, xmitq);
 }
 
 void tipc_link_set_prio(struct tipc_link *l, u32 prio,

net/tipc/node.c

@@ -1618,6 +1618,30 @@ void tipc_rcv(struct net *net, struct sk_buff *skb, struct tipc_bearer *b)
 	kfree_skb(skb);
 }
 
+void tipc_node_apply_tolerance(struct net *net, struct tipc_bearer *b)
+{
+	struct tipc_net *tn = tipc_net(net);
+	int bearer_id = b->identity;
+	struct sk_buff_head xmitq;
+	struct tipc_link_entry *e;
+	struct tipc_node *n;
+
+	__skb_queue_head_init(&xmitq);
+
+	rcu_read_lock();
+
+	list_for_each_entry_rcu(n, &tn->node_list, list) {
+		tipc_node_write_lock(n);
+		e = &n->links[bearer_id];
+		if (e->link)
+			tipc_link_set_tolerance(e->link, b->tolerance, &xmitq);
+		tipc_node_write_unlock(n);
+		tipc_bearer_xmit(net, bearer_id, &xmitq, &e->maddr);
+	}
+
+	rcu_read_unlock();
+}
+
 int tipc_nl_peer_rm(struct sk_buff *skb, struct genl_info *info)
 {
 	struct net *net = sock_net(skb->sk);

net/tipc/node.h

@@ -65,6 +65,7 @@ void tipc_node_check_dest(struct net *net, u32 onode,
 			  struct tipc_media_addr *maddr,
 			  bool *respond, bool *dupl_addr);
 void tipc_node_delete_links(struct net *net, int bearer_id);
+void tipc_node_apply_tolerance(struct net *net, struct tipc_bearer *b);
 int tipc_node_get_linkname(struct net *net, u32 bearer_id, u32 node,
 			   char *linkname, size_t len);
 int tipc_node_xmit(struct net *net, struct sk_buff_head *list, u32 dnode,