From dc1571f84c8995170423acbd2865d389699c52ce Mon Sep 17 00:00:00 2001
From: Jiri Pirko <jiri@mellanox.com>
Date: Sat, 25 Jan 2020 12:17:08 +0100
Subject: [PATCH] BACKPORT: net: introduce dev_net notifier register/unregister
 variants

Introduce dev_net variants of netdev notifier register/unregister functions
and allow per-net notifier to follow the netdevice into the namespace it is
moved to.

Change-Id: I3571ddd23aaa7f80f2ea0bbdc899b5a883b53ffa
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/netdevice.h | 17 +++++++++++++++
 net/core/dev.c            | 46 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3e101a3bf1e8..d84e55997f5f 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -960,6 +960,11 @@ struct devlink;
 struct tlsdev_ops;
 
 
+struct netdev_net_notifier {
+	struct list_head list;
+	struct notifier_block *nb;
+};
+
 /*
  * This structure defines the management hooks for network devices.
  * The following hooks can be defined; unless noted otherwise, they are
@@ -1816,6 +1821,10 @@ enum netdev_priv_flags {
  *
  *	@wol_enabled:	Wake-on-LAN is enabled
  *
+ *	@net_notifier_list:	List of per-net netdev notifier block
+ *				that follow this device when it is moved
+ *				to another network namespace.
+ *
  *	@macsec_ops:    MACsec offloading ops
  *
  *	FIXME: cleanup struct net_device such that network protocol info
@@ -2108,6 +2117,8 @@ struct net_device {
 	bool			proto_down;
 	unsigned		wol_enabled:1;
 
+	struct list_head	net_notifier_list;
+
 #if IS_ENABLED(CONFIG_MACSEC)
 	/* MACsec management functions */
 	const struct macsec_ops *macsec_ops;
@@ -2565,6 +2576,12 @@ int unregister_netdevice_notifier(struct notifier_block *nb);
 int register_netdevice_notifier_net(struct net *net, struct notifier_block *nb);
 int unregister_netdevice_notifier_net(struct net *net,
 				      struct notifier_block *nb);
+int register_netdevice_notifier_dev_net(struct net_device *dev,
+					struct notifier_block *nb,
+					struct netdev_net_notifier *nn);
+int unregister_netdevice_notifier_dev_net(struct net_device *dev,
+					  struct notifier_block *nb,
+					  struct netdev_net_notifier *nn);
 
 struct netdev_notifier_info {
 	struct net_device	*dev;
diff --git a/net/core/dev.c b/net/core/dev.c
index 179a3467b9af..f3112a27d51e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1777,6 +1777,48 @@ int unregister_netdevice_notifier_net(struct net *net,
 }
 EXPORT_SYMBOL(unregister_netdevice_notifier_net);
 
+int register_netdevice_notifier_dev_net(struct net_device *dev,
+					struct notifier_block *nb,
+					struct netdev_net_notifier *nn)
+{
+	int err;
+
+	rtnl_lock();
+	err = __register_netdevice_notifier_net(dev_net(dev), nb, false);
+	if (!err) {
+		nn->nb = nb;
+		list_add(&nn->list, &dev->net_notifier_list);
+	}
+	rtnl_unlock();
+	return err;
+}
+EXPORT_SYMBOL(register_netdevice_notifier_dev_net);
+
+int unregister_netdevice_notifier_dev_net(struct net_device *dev,
+					  struct notifier_block *nb,
+					  struct netdev_net_notifier *nn)
+{
+	int err;
+
+	rtnl_lock();
+	list_del(&nn->list);
+	err = __unregister_netdevice_notifier_net(dev_net(dev), nb);
+	rtnl_unlock();
+	return err;
+}
+EXPORT_SYMBOL(unregister_netdevice_notifier_dev_net);
+
+static void move_netdevice_notifiers_dev_net(struct net_device *dev,
+					     struct net *net)
+{
+	struct netdev_net_notifier *nn;
+
+	list_for_each_entry(nn, &dev->net_notifier_list, list) {
+		__unregister_netdevice_notifier_net(dev_net(dev), nn->nb);
+		__register_netdevice_notifier_net(net, nn->nb, true);
+	}
+}
+
 /**
  *	call_netdevice_notifiers_info - call all network notifier blocks
  *	@val: value passed unmodified to notifier function
@@ -9891,6 +9933,7 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
 	INIT_LIST_HEAD(&dev->adj_list.lower);
 	INIT_LIST_HEAD(&dev->ptype_all);
 	INIT_LIST_HEAD(&dev->ptype_specific);
+	INIT_LIST_HEAD(&dev->net_notifier_list);
 #ifdef CONFIG_NET_SCHED
 	hash_init(dev->qdisc_hash);
 #endif
@@ -10154,6 +10197,9 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 	kobject_uevent(&dev->dev.kobj, KOBJ_REMOVE);
 	netdev_adjacent_del_links(dev);
 
+	/* Move per-net netdevice notifiers that are following the netdevice */
+	move_netdevice_notifiers_dev_net(dev, net);
+
 	/* Actually switch the network namespace */
 	dev_net_set(dev, net);
 	dev->ifindex = new_ifindex;