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tipc: purge backlog queue counters when broadcast link is reset

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In commit 1f66d161ab
("tipc: introduce starvation free send algorithm")
we introduced a counter per priority level for buffers
in the link backlog queue. We also introduced a new
function tipc_link_purge_backlog(), to reset these
counters to zero when the link is reset.

Unfortunately, we missed to call this function when
the broadcast link is reset, with the result that the
values of these counters might be permanently skewed
when new nodes are attached. This may in the worst case
lead to permananent, but spurious, broadcast link
congestion, where no broadcast packets can be sent at
all.

We fix this bug with this commit.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jon Paul Maloy 2015-06-28 09:44:44 -04:00 committed by David S. Miller
parent 011cb197a8
commit 7d967b673c
3 changed files with 7 additions and 1 deletions
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5
net/tipc/bcast.c
View file

@ -108,6 +108,11 @@ void tipc_bclink_remove_node(struct net *net, u32 addr)
tipc_bclink_lock(net);
tipc_nmap_remove(&tn->bclink->bcast_nodes, addr);
/* Last node? => reset backlog queue */
if (!tn->bclink->bcast_nodes.count)
tipc_link_purge_backlog(&tn->bclink->link);
tipc_bclink_unlock(net);
}

2
net/tipc/link.c
View file

@ -404,7 +404,7 @@ void tipc_link_reset_fragments(struct tipc_link *l_ptr)
l_ptr->reasm_buf = NULL;
}
static void tipc_link_purge_backlog(struct tipc_link *l)
void tipc_link_purge_backlog(struct tipc_link *l)
{
__skb_queue_purge(&l->backlogq);
l->backlog[TIPC_LOW_IMPORTANCE].len = 0;

1
net/tipc/link.h
View file

@ -218,6 +218,7 @@ void tipc_link_reset_fragments(struct tipc_link *l_ptr);
int tipc_link_is_up(struct tipc_link *l_ptr);
int tipc_link_is_active(struct tipc_link *l_ptr);
void tipc_link_purge_queues(struct tipc_link *l_ptr);
void tipc_link_purge_backlog(struct tipc_link *l);
void tipc_link_reset_all(struct tipc_node *node);
void tipc_link_reset(struct tipc_link *l_ptr);
int tipc_link_xmit_skb(struct net *net, struct sk_buff *skb, u32 dest,