geneve: break dependency with netdev drivers

Equivalent to "vxlan: break dependency with netdev drivers", don't
autoload geneve module in case the driver is loaded. Instead make the
coupling weaker by using netdevice notifiers as proxy.

Cc: Jesse Gross <jesse@kernel.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 31 insertions, 7 deletions

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 512dbe013713..9c40b88fabd5 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1172,7 +1172,7 @@ static struct device_type geneve_type = {
  * supply the listening GENEVE udp ports. Callers are expected
  * to implement the ndo_add_geneve_port.
  */
-void geneve_get_rx_port(struct net_device *dev)
+static void geneve_push_rx_ports(struct net_device *dev)
 {
         struct net *net = dev_net(dev);
         struct geneve_net *gn = net_generic(net, geneve_net_id);
@@ -1181,6 +1181,9 @@ void geneve_get_rx_port(struct net_device *dev)
         struct sock *sk;
         __be16 port;
 
+        if (!dev->netdev_ops->ndo_add_geneve_port)
+                return;
+
         rcu_read_lock();
         list_for_each_entry_rcu(gs, &gn->sock_list, list) {
                 sk = gs->sock->sk;
@@ -1190,7 +1193,6 @@ void geneve_get_rx_port(struct net_device *dev)
         }
         rcu_read_unlock();
 }
-EXPORT_SYMBOL_GPL(geneve_get_rx_port);
 
 /* Initialize the device structure. */
 static void geneve_setup(struct net_device *dev)
@@ -1538,6 +1540,21 @@ struct net_device *geneve_dev_create_fb(struct net *net, const char *name,
 }
 EXPORT_SYMBOL_GPL(geneve_dev_create_fb);
 
+static int geneve_netdevice_event(struct notifier_block *unused,
+                                  unsigned long event, void *ptr)
+{
+        struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+        if (event == NETDEV_OFFLOAD_PUSH_GENEVE)
+                geneve_push_rx_ports(dev);
+
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block geneve_notifier_block __read_mostly = {
+        .notifier_call = geneve_netdevice_event,
+};
+
 static __net_init int geneve_init_net(struct net *net)
 {
         struct geneve_net *gn = net_generic(net, geneve_net_id);
@@ -1590,11 +1607,18 @@ static int __init geneve_init_module(void)
         if (rc)
                 goto out1;
 
-        rc = rtnl_link_register(&geneve_link_ops);
+        rc = register_netdevice_notifier(&geneve_notifier_block);
         if (rc)
                 goto out2;
 
+        rc = rtnl_link_register(&geneve_link_ops);
+        if (rc)
+                goto out3;
+
         return 0;
+
+out3:
+        unregister_netdevice_notifier(&geneve_notifier_block);
 out2:
         unregister_pernet_subsys(&geneve_net_ops);
 out1:
@@ -1605,6 +1629,7 @@ late_initcall(geneve_init_module);
 static void __exit geneve_cleanup_module(void)
 {
         rtnl_link_unregister(&geneve_link_ops);
+        unregister_netdevice_notifier(&geneve_notifier_block);
         unregister_pernet_subsys(&geneve_net_ops);
 }
 module_exit(geneve_cleanup_module);
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index d4c8cd424f8d..1f6d5db471a2 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2245,6 +2245,7 @@ struct netdev_lag_lower_state_info {
 #define NETDEV_PRECHANGEUPPER   0x001A
 #define NETDEV_CHANGELOWERSTATE 0x001B
 #define NETDEV_OFFLOAD_PUSH_VXLAN       0x001C
+#define NETDEV_OFFLOAD_PUSH_GENEVE      0x001D
 
 int register_netdevice_notifier(struct notifier_block *nb);
 int unregister_netdevice_notifier(struct notifier_block *nb);
diff --git a/include/net/geneve.h b/include/net/geneve.h
index e6c23dc765f7..cb544a530146 100644
--- a/include/net/geneve.h
+++ b/include/net/geneve.h
@@ -62,13 +62,11 @@ struct genevehdr {
         struct geneve_opt options[];
 };
 
-#if IS_ENABLED(CONFIG_GENEVE)
-void geneve_get_rx_port(struct net_device *netdev);
-#else
 static inline void geneve_get_rx_port(struct net_device *netdev)
 {
+        ASSERT_RTNL();
+        call_netdevice_notifiers(NETDEV_OFFLOAD_PUSH_GENEVE, netdev);
 }
-#endif
 
 #ifdef CONFIG_INET
 struct net_device *geneve_dev_create_fb(struct net *net, const char *name,