bridge: multicast port group RCU fix

The recently introduced bridge mulitcast port group list was only
partially using RCU correctly. It was missing rcu_dereference()
and missing the necessary barrier on deletion.

The code should have used one of the standard list methods (list or hlist)
instead of open coding a RCU based link list.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 3 insertions, 3 deletions

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 5b70fc012e40..5f9988a3f06a 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -217,7 +217,7 @@ static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
         prev = NULL;
 
         rp = rcu_dereference(br->router_list.first);
-        p = mdst ? mdst->ports : NULL;
+        p = mdst ? rcu_dereference(mdst->ports) : NULL;
         while (p || rp) {
                 lport = p ? p->port : NULL;
                 rport = rp ? hlist_entry(rp, struct net_bridge_port, rlist) :
@@ -231,7 +231,7 @@ static void br_multicast_flood(struct net_bridge_mdb_entry *mdst,
                         goto out;
 
                 if ((unsigned long)lport >= (unsigned long)port)
-                        p = p->next;
+                        p = rcu_dereference(p->next);
                 if ((unsigned long)rport >= (unsigned long)port)
                         rp = rcu_dereference(rp->next);
         }
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index d63868c9b2c0..7128abdce45f 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -259,7 +259,7 @@ static void br_multicast_del_pg(struct net_bridge *br,
                 if (p != pg)
                         continue;
 
-                *pp = p->next;
+                rcu_assign_pointer(*pp, p->next);
                 hlist_del_init(&p->mglist);
                 del_timer(&p->timer);
                 del_timer(&p->query_timer);