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Commit c8199300 authored by Jon Paul Maloy's avatar Jon Paul Maloy Committed by David S. Miller
Browse files

tipc: update node FSM when peer RESET message is received 



The change made in the previous commit revealed a small flaw in the way
the node FSM is updated. When the function tipc_node_link_down() is
called for the last link to a node, we should check whether this was
caused by a local reset or by a received RESET message from the peer.
In the latter case, we can directly issue a PEER_LOST_CONTACT_EVT to
the node FSM, so that it is ready to re-establish contact. If this is
not done, the peer node will sometimes have to go through a second
establish cycle before the link becomes stable.

We fix this in this commit by conditionally issuing the mentioned
event in the function tipc_node_link_down(). We also move LINK_RESET
FSM even away from the link_reset() function and into the caller
function, partially because it is easier to follow the code when state
changes are gathered at a limited number of locations, partially
because there will be cases in future commits where we don't want the
link to go RESET mode when link_reset() is called.

Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Acked-by: default avatarYing Xue <ying.xue@windriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 282b3a05

net/tipc/link.c

+5 −2
Original line number Diff line number Diff line
@@ -120,6 +120,11 @@ bool tipc_link_is_up(struct tipc_link *l) 
	return link_is_up(l);

}



bool tipc_link_peer_is_down(struct tipc_link *l)

{

	return l->state == LINK_PEER_RESET;

}



bool tipc_link_is_reset(struct tipc_link *l)

{

	return l->state & (LINK_RESET | LINK_FAILINGOVER | LINK_ESTABLISHING);
@@ -584,8 +589,6 @@ void tipc_link_purge_queues(struct tipc_link *l_ptr) 


void tipc_link_reset(struct tipc_link *l)

{

	tipc_link_fsm_evt(l, LINK_RESET_EVT);



	/* Link is down, accept any session */

	l->peer_session = WILDCARD_SESSION;

net/tipc/link.h

+1 −0
Original line number Diff line number Diff line
@@ -217,6 +217,7 @@ void tipc_link_build_reset_msg(struct tipc_link *l, struct sk_buff_head *xmitq); 
int tipc_link_fsm_evt(struct tipc_link *l, int evt);

void tipc_link_reset_fragments(struct tipc_link *l_ptr);

bool tipc_link_is_up(struct tipc_link *l);

bool tipc_link_peer_is_down(struct tipc_link *l);

bool tipc_link_is_reset(struct tipc_link *l);

bool tipc_link_is_establishing(struct tipc_link *l);

bool tipc_link_is_synching(struct tipc_link *l);

net/tipc/node.c

+7 −4
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ 
#include "socket.h"

#include "bcast.h"

#include "discover.h"

#define pr_debug printk



/* Node FSM states and events:

 */

enum {
@@ -420,6 +420,10 @@ static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id, 
	}



	if (!tipc_node_is_up(n)) {

		if (tipc_link_peer_is_down(l))

			tipc_node_fsm_evt(n, PEER_LOST_CONTACT_EVT);

		tipc_node_fsm_evt(n, SELF_LOST_CONTACT_EVT);

		tipc_link_fsm_evt(l, LINK_RESET_EVT);

		tipc_link_reset(l);

		tipc_link_build_reset_msg(l, xmitq);

		*maddr = &n->links[*bearer_id].maddr;
@@ -434,6 +438,7 @@ static void __tipc_node_link_down(struct tipc_node *n, int *bearer_id, 
	n->sync_point = tnl->rcv_nxt + (U16_MAX / 2 - 1);

	tipc_link_tnl_prepare(l, tnl, FAILOVER_MSG, xmitq);

	tipc_link_reset(l);

	tipc_link_fsm_evt(l, LINK_RESET_EVT);

	tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);

	tipc_node_fsm_evt(n, NODE_FAILOVER_BEGIN_EVT);

	*maddr = &n->links[tnl->bearer_id].maddr;
@@ -581,6 +586,7 @@ void tipc_node_check_dest(struct net *net, u32 onode, 
			goto exit;

		}

		tipc_link_reset(l);

		tipc_link_fsm_evt(l, LINK_RESET_EVT);

		if (n->state == NODE_FAILINGOVER)

			tipc_link_fsm_evt(l, LINK_FAILOVER_BEGIN_EVT);

		le->link = l;
@@ -863,9 +869,6 @@ static void node_lost_contact(struct tipc_node *n_ptr, 
			tipc_link_fsm_evt(l, LINK_FAILOVER_END_EVT);

	}



	/* Prevent re-contact with node until cleanup is done */

	tipc_node_fsm_evt(n_ptr, SELF_LOST_CONTACT_EVT);



	/* Notify publications from this node */

	n_ptr->action_flags |= TIPC_NOTIFY_NODE_DOWN;