vxlan: use exit_batch_rtnl() method

exit_batch_rtnl() is called while RTNL is held,
and devices to be unregistered can be queued in the dev_kill_list.

This saves one rtnl_lock()/rtnl_unlock() pair per netns
and one unregister_netdevice_many() call.

v4: (Paolo feedback : https://netdev-3.bots.linux.dev/vmksft-net/results/453141/17-udpgro-fwd-sh/stdout )
  - Changed vxlan_destroy_tunnels() to use vxlan_dellink()
    instead of unregister_netdevice_queue to propely remove
    devices from vn->vxlan_list.
  - vxlan_destroy_tunnels() can simply iterate one list (vn->vxlan_list)
    to find all devices in the most efficient way.
  - Moved sanity checks in a separate vxlan_exit_net() method.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Antoine Tenart <atenart@kernel.org>
Link: https://lore.kernel.org/r/20240206144313.2050392-10-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/vxlan/vxlan_core.c b/drivers/net/vxlan/vxlan_core.c
index 16106e088c6301d3aaa47dd73985107945735b6e..11707647afb9831ee430cdc13e705431b66af6c2 100644 (file)
--- a/drivers/net/vxlan/vxlan_core.c
+++ b/drivers/net/vxlan/vxlan_core.c
@@ -4826,55 +4826,43 @@ static __net_init int vxlan_init_net(struct net *net)
                                         NULL);
 }
 
-static void vxlan_destroy_tunnels(struct net *net, struct list_head *head)
+static void __net_exit vxlan_destroy_tunnels(struct vxlan_net *vn,
+                                            struct list_head *dev_to_kill)
 {
-       struct vxlan_net *vn = net_generic(net, vxlan_net_id);
        struct vxlan_dev *vxlan, *next;
-       struct net_device *dev, *aux;
-
-       for_each_netdev_safe(net, dev, aux)
-               if (dev->rtnl_link_ops == &vxlan_link_ops)
-                       unregister_netdevice_queue(dev, head);
-
-       list_for_each_entry_safe(vxlan, next, &vn->vxlan_list, next) {
-               /* If vxlan->dev is in the same netns, it has already been added
-                * to the list by the previous loop.
-                */
-               if (!net_eq(dev_net(vxlan->dev), net))
-                       unregister_netdevice_queue(vxlan->dev, head);
-       }
 
+       list_for_each_entry_safe(vxlan, next, &vn->vxlan_list, next)
+               vxlan_dellink(vxlan->dev, dev_to_kill);
 }
 
-static void __net_exit vxlan_exit_batch_net(struct list_head *net_list)
+static void __net_exit vxlan_exit_batch_rtnl(struct list_head *net_list,
+                                            struct list_head *dev_to_kill)
 {
        struct net *net;
-       LIST_HEAD(list);
-       unsigned int h;
 
+       ASSERT_RTNL();
        list_for_each_entry(net, net_list, exit_list) {
                struct vxlan_net *vn = net_generic(net, vxlan_net_id);
 
-               unregister_nexthop_notifier(net, &vn->nexthop_notifier_block);
-       }
-       rtnl_lock();
-       list_for_each_entry(net, net_list, exit_list)
-               vxlan_destroy_tunnels(net, &list);
+               __unregister_nexthop_notifier(net, &vn->nexthop_notifier_block);
 
-       unregister_netdevice_many(&list);
-       rtnl_unlock();
+               vxlan_destroy_tunnels(vn, dev_to_kill);
+       }
+}
 
-       list_for_each_entry(net, net_list, exit_list) {
-               struct vxlan_net *vn = net_generic(net, vxlan_net_id);
+static void __net_exit vxlan_exit_net(struct net *net)
+{
+       struct vxlan_net *vn = net_generic(net, vxlan_net_id);
+       unsigned int h;
 
-               for (h = 0; h < PORT_HASH_SIZE; ++h)
-                       WARN_ON_ONCE(!hlist_empty(&vn->sock_list[h]));
-       }
+       for (h = 0; h < PORT_HASH_SIZE; ++h)
+               WARN_ON_ONCE(!hlist_empty(&vn->sock_list[h]));
 }
 
 static struct pernet_operations vxlan_net_ops = {
        .init = vxlan_init_net,
-       .exit_batch = vxlan_exit_batch_net,
+       .exit_batch_rtnl = vxlan_exit_batch_rtnl,
+       .exit = vxlan_exit_net,
        .id   = &vxlan_net_id,
        .size = sizeof(struct vxlan_net),
 };