bridge: fix hang on removal of bridge via netlink

[ Upstream commit 1ce5cce8 ]

Need to cleanup bridge device timers and ports when being bridge
device is being removed via netlink.

This fixes the problem of observed when doing:
 ip link add br0 type bridge
 ip link set dev eth1 master br0
 ip link set br0 up
 ip link del br0

which would cause br0 to hang in unregister_netdev because
of leftover reference count.
Reported-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

net/bridge/br_if.c

@@ -161,9 +161,10 @@ static void del_nbp(struct net_bridge_port *p)
 	call_rcu(&p->rcu, destroy_nbp_rcu);
 }
 
-/* called with RTNL */
-static void del_br(struct net_bridge *br, struct list_head *head)
+/* Delete bridge device */
+void br_dev_delete(struct net_device *dev, struct list_head *head)
 {
+	struct net_bridge *br = netdev_priv(dev);
 	struct net_bridge_port *p, *n;
 
 	list_for_each_entry_safe(p, n, &br->port_list, list) {
@@ -268,7 +269,7 @@ int br_del_bridge(struct net *net, const char *name)
 	}
 
 	else
-		del_br(netdev_priv(dev), NULL);
+		br_dev_delete(dev, NULL);
 
 	rtnl_unlock();
 	return ret;
@@ -445,7 +446,7 @@ void __net_exit br_net_exit(struct net *net)
 	rtnl_lock();
 	for_each_netdev(net, dev)
 		if (dev->priv_flags & IFF_EBRIDGE)
-			del_br(netdev_priv(dev), &list);
+			br_dev_delete(dev, &list);
 
 	unregister_netdevice_many(&list);
 	rtnl_unlock();

net/bridge/br_netlink.c

@@ -208,6 +208,7 @@ static struct rtnl_link_ops br_link_ops __read_mostly = {
 	.priv_size	= sizeof(struct net_bridge),
 	.setup		= br_dev_setup,
 	.validate	= br_validate,
+	.dellink	= br_dev_delete,
 };
 
 int __init br_netlink_init(void)

net/bridge/br_private.h

@@ -294,6 +294,7 @@ static inline int br_is_root_bridge(const struct net_bridge *br)
 
 /* br_device.c */
 extern void br_dev_setup(struct net_device *dev);
+extern void br_dev_delete(struct net_device *dev, struct list_head *list);
 extern netdev_tx_t br_dev_xmit(struct sk_buff *skb,
 			       struct net_device *dev);
 #ifdef CONFIG_NET_POLL_CONTROLLER