tipc: move link input queue to tipc_node

At present, the link input queue and the name distributor receive
queues are fields aggregated in struct tipc_link. This is a hazard,
because a link might be deleted while a receiving socket still keeps
reference to one of the queues.

This commit fixes this bug. However, rather than adding yet another
reference counter to the critical data path, we move the two queues
to safe ground inside struct tipc_node, which is already protected, and
let the link code only handle references to the queues. This is also
in line with planned later changes in this area.

Reviewed-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>

1 files changed, 3 insertions, 1 deletions

diff --git a/net/tipc/node.c b/net/tipc/node.c
index 06f642abdf38..20ec61ceffac 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -132,6 +132,7 @@ struct tipc_node *tipc_node_create(struct net *net, u32 addr)
         INIT_LIST_HEAD(&n_ptr->list);
         INIT_LIST_HEAD(&n_ptr->publ_list);
         INIT_LIST_HEAD(&n_ptr->conn_sks);
+        skb_queue_head_init(&n_ptr->bclink.namedq);
         __skb_queue_head_init(&n_ptr->bclink.deferdq);
         hlist_add_head_rcu(&n_ptr->hash, &tn->node_htable[tipc_hashfn(addr)]);
         list_for_each_entry_rcu(temp_node, &tn->node_list, list) {
@@ -350,9 +351,10 @@ bool tipc_node_update_dest(struct tipc_node *n,  struct tipc_bearer *b,
 {
         struct tipc_link *l = n->links[b->identity].link;
         struct tipc_media_addr *curr = &n->links[b->identity].maddr;
+        struct sk_buff_head *inputq = &n->links[b->identity].inputq;
 
         if (!l)
-                l = tipc_link_create(n, b, maddr);
+                l = tipc_link_create(n, b, maddr, inputq, &n->bclink.namedq);
         if (!l)
                 return false;
         memcpy(&l->media_addr, maddr, sizeof(*maddr));