2 files changed, 62 insertions, 1 deletions

diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c
index c6688b604337..5c417c6055d8 100644
--- a/drivers/net/netkit.c
+++ b/drivers/net/netkit.c
@@ -1039,6 +1039,48 @@ static int netkit_change_link(struct net_device *dev, struct nlattr *tb[],
 	return 0;
 }
 
+static void netkit_check_lease_unregister(struct net_device *dev)
+{
+	LIST_HEAD(list_kill);
+	u32 q_idx;
+
+	if (READ_ONCE(dev->reg_state) != NETREG_UNREGISTERING ||
+	    !dev->dev.parent)
+		return;
+
+	netdev_lock_ops(dev);
+	for (q_idx = 0; q_idx < dev->real_num_rx_queues; q_idx++) {
+		struct net_device *tmp = dev;
+		u32 tmp_q_idx = q_idx;
+
+		if (netif_rx_queue_lease_get_owner(&tmp, &tmp_q_idx)) {
+			if (tmp->netdev_ops != &netkit_netdev_ops)
+				continue;
+			/* A single phys device can have multiple queues leased
+			 * to one netkit device. We can only queue that netkit
+			 * device once to the list_kill. Queues of that phys
+			 * device can be leased with different individual netkit
+			 * devices, hence we batch via list_kill.
+			 */
+			if (unregister_netdevice_queued(tmp))
+				continue;
+			netkit_del_link(tmp, &list_kill);
+		}
+	}
+	netdev_unlock_ops(dev);
+	unregister_netdevice_many(&list_kill);
+}
+
+static int netkit_notifier(struct notifier_block *this,
+			   unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+	if (event == NETDEV_UNREGISTER)
+		netkit_check_lease_unregister(dev);
+	return NOTIFY_DONE;
+}
+
 static size_t netkit_get_size(const struct net_device *dev)
 {
 	return nla_total_size(sizeof(u32)) + /* IFLA_NETKIT_POLICY */
@@ -1115,18 +1157,31 @@ static struct rtnl_link_ops netkit_link_ops = {
 	.maxtype	= IFLA_NETKIT_MAX,
 };
 
+static struct notifier_block netkit_netdev_notifier = {
+	.notifier_call	= netkit_notifier,
+};
+
 static __init int netkit_mod_init(void)
 {
+	int ret;
+
 	BUILD_BUG_ON((int)NETKIT_NEXT != (int)TCX_NEXT ||
 		     (int)NETKIT_PASS != (int)TCX_PASS ||
 		     (int)NETKIT_DROP != (int)TCX_DROP ||
 		     (int)NETKIT_REDIRECT != (int)TCX_REDIRECT);
 
-	return rtnl_link_register(&netkit_link_ops);
+	ret = rtnl_link_register(&netkit_link_ops);
+	if (ret)
+		return ret;
+	ret = register_netdevice_notifier(&netkit_netdev_notifier);
+	if (ret)
+		rtnl_link_unregister(&netkit_link_ops);
+	return ret;
 }
 
 static __exit void netkit_mod_exit(void)
 {
+	unregister_netdevice_notifier(&netkit_netdev_notifier);
 	rtnl_link_unregister(&netkit_link_ops);
 }
 
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d99b0fbc1942..4d146c000e21 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3400,11 +3400,17 @@ static inline int dev_direct_xmit(struct sk_buff *skb, u16 queue_id)
 int register_netdevice(struct net_device *dev);
 void unregister_netdevice_queue(struct net_device *dev, struct list_head *head);
 void unregister_netdevice_many(struct list_head *head);
+
 static inline void unregister_netdevice(struct net_device *dev)
 {
 	unregister_netdevice_queue(dev, NULL);
 }
 
+static inline bool unregister_netdevice_queued(const struct net_device *dev)
+{
+	return !list_empty(&dev->unreg_list);
+}
+
 int netdev_refcnt_read(const struct net_device *dev);
 void free_netdev(struct net_device *dev);