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tipc: delay delete of link when failover is needed

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When a bearer is disabled, all its attached links are deleted.
Ideally, we should do link failover to redundant links on other bearers,
if there are any, in such cases. This would be consistent with current
behavior when a link is reset, but not deleted. However, due to the
complexity involved, and the (wrongly) perceived low demand for this
feature, it was never implemented until now.

We mark the doomed link for deletion with a new flag, but wait until the
failover process is finished before we actually delete it. With the
improved link tunnelling/failover code introduced earlier in this commit
series, it is now easy to identify a spot in the code where the failover
is finished and it is safe to delete the marked link. Moreover, the test
for the flag and the deletion can be done synchronously, and outside the
most time critical data path.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Reviewed-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jon Paul Maloy
2014-02-13 17:29:16 -05:00
committed by David S. Miller
parent a5377831eb
commit 7d33939f47
4 changed files with 35 additions and 16 deletions
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29
net/tipc/link.c
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@@ -281,7 +281,7 @@ struct tipc_link *tipc_link_create(struct tipc_node *n_ptr,
}
void tipc_link_delete_list(unsigned int bearer_id)
void tipc_link_delete_list(unsigned int bearer_id, bool shutting_down)
{
struct tipc_link *l_ptr;
struct tipc_node *n_ptr;
@@ -291,12 +291,20 @@ void tipc_link_delete_list(unsigned int bearer_id)
l_ptr = n_ptr->links[bearer_id];
if (l_ptr) {
tipc_link_reset(l_ptr);
tipc_node_detach_link(n_ptr, l_ptr);
spin_unlock_bh(&n_ptr->lock);
if (shutting_down || !tipc_node_is_up(n_ptr)) {
tipc_node_detach_link(l_ptr->owner, l_ptr);
tipc_link_reset_fragments(l_ptr);
spin_unlock_bh(&n_ptr->lock);
/* Nobody else can access this link now: */
del_timer_sync(&l_ptr->timer);
kfree(l_ptr);
/* Nobody else can access this link now: */
del_timer_sync(&l_ptr->timer);
kfree(l_ptr);
} else {
/* Detach/delete when failover is finished: */
l_ptr->flags |= LINK_STOPPED;
spin_unlock_bh(&n_ptr->lock);
del_timer_sync(&l_ptr->timer);
}
continue;
}
spin_unlock_bh(&n_ptr->lock);
@@ -481,6 +489,9 @@ static void link_state_event(struct tipc_link *l_ptr, unsigned int event)
struct tipc_link *other;
u32 cont_intv = l_ptr->continuity_interval;
if (l_ptr->flags & LINK_STOPPED)
return;
if (!(l_ptr->flags & LINK_STARTED) && (event != STARTING_EVT))
return; /* Not yet. */
@@ -2167,8 +2178,11 @@ static struct sk_buff *tipc_link_failover_rcv(struct tipc_link *l_ptr,
&buf);
}
}
exit:
if ((l_ptr->exp_msg_count == 0) && (l_ptr->flags & LINK_STOPPED)) {
tipc_node_detach_link(l_ptr->owner, l_ptr);
kfree(l_ptr);
}
return buf;
}
@@ -2201,7 +2215,6 @@ static int tipc_link_tunnel_rcv(struct tipc_node *n_ptr,
*buf = tipc_link_failover_rcv(l_ptr, t_buf);
else
pr_warn("%sunknown tunnel pkt received\n", link_co_err);
exit:
kfree_skb(t_buf);
return *buf != NULL;