geneve: speedup geneve tunnels dismantle

Since we now hold RTNL lock in geneve_exit_net, it's better batch them
to speedup geneve tunnel dismantle.

Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/geneve.c

@@ -1638,38 +1638,46 @@ static __net_init int geneve_init_net(struct net *net)
  return 0;
 }
 
-static void __net_exit geneve_exit_net(struct net *net)
+static void geneve_destroy_tunnels(struct net *net, struct list_head *head)
 {
  struct geneve_net *gn = net_generic(net, geneve_net_id);
  struct geneve_dev *geneve, *next;
  struct net_device *dev, *aux;
- LIST_HEAD(list);
-
- rtnl_lock();
 
  /* gather any geneve devices that were moved into this ns */
  for_each_netdev_safe(net, dev, aux)
  if (dev->rtnl_link_ops == &geneve_link_ops)
- unregister_netdevice_queue(dev, &list);
+ unregister_netdevice_queue(dev, head);
 
  /* now gather any other geneve devices that were created in this ns */
  list_for_each_entry_safe(geneve, next, &gn->geneve_list, next) {
  /* If geneve->dev is in the same netns, it was already added
  * to the list by the previous loop.
  */
  if (!net_eq(dev_net(geneve->dev), net))
- unregister_netdevice_queue(geneve->dev, &list);
+ unregister_netdevice_queue(geneve->dev, head);
  }
 
+ WARN_ON_ONCE(!list_empty(&gn->sock_list));
+}
+
+static void __net_exit geneve_exit_batch_net(struct list_head *net_list)
+{
+ struct net *net;
+ LIST_HEAD(list);
+
+ rtnl_lock();
+ list_for_each_entry(net, net_list, exit_list)
+ geneve_destroy_tunnels(net, &list);
+
  /* unregister the devices gathered above */
  unregister_netdevice_many(&list);
  rtnl_unlock();
- WARN_ON_ONCE(!list_empty(&gn->sock_list));
 }
 
 static struct pernet_operations geneve_net_ops = {
  .init = geneve_init_net,
- .exit = geneve_exit_net,
+ .exit_batch = geneve_exit_batch_net,
  .id = &geneve_net_id,
  .size = sizeof(struct geneve_net),
 };