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tipc: update node FSM when peer RESET message is received

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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: Jon Maloy <jon.maloy@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jon Paul Maloy 2015-10-15 14:52:46 -04:00 committed by David S. Miller
parent 282b3a0562
commit c819930090
3 changed files with 13 additions and 6 deletions
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7
net/tipc/link.c
View File

@ -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;

1
net/tipc/link.h
View File

@ -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);

11
net/tipc/node.c
View File

@ -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;