net: introduce NETDEV_UNREGISTER_PERNET

This new event is called once for each unique net namespace in batched
unregister operations (with the argument set to a random device from
that namespace) and once per device in non-batched unregister
operations.

It allows us to factorize some device unregister work such as clearing the
routing cache.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 27 insertions, 2 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index c3e0578d29d1..e25fe5d9343b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1344,6 +1344,7 @@ rollback:
                                 nb->notifier_call(nb, NETDEV_DOWN, dev);
                         }
                         nb->notifier_call(nb, NETDEV_UNREGISTER, dev);
+                        nb->notifier_call(nb, NETDEV_UNREGISTER_PERNET, dev);
                 }
         }
 
@@ -4721,7 +4722,8 @@ static void net_set_todo(struct net_device *dev)
 
 static void rollback_registered_many(struct list_head *head)
 {
-        struct net_device *dev;
+        struct net_device *dev, *aux, *fdev;
+        LIST_HEAD(pernet_list);
 
         BUG_ON(dev_boot_phase);
         ASSERT_RTNL();
@@ -4779,8 +4781,24 @@ static void rollback_registered_many(struct list_head *head)
 
         synchronize_net();
 
-        list_for_each_entry(dev, head, unreg_list)
+        list_for_each_entry_safe(dev, aux, head, unreg_list) {
+                int new_net = 1;
+                list_for_each_entry(fdev, &pernet_list, unreg_list) {
+                        if (dev_net(dev) == dev_net(fdev)) {
+                                new_net = 0;
+                                dev_put(dev);
+                                break;
+                        }
+                }
+                if (new_net)
+                        list_move(&dev->unreg_list, &pernet_list);
+        }
+
+        list_for_each_entry_safe(dev, aux, &pernet_list, unreg_list) {
+                call_netdevice_notifiers(NETDEV_UNREGISTER_PERNET, dev);
+                list_move(&dev->unreg_list, head);
                 dev_put(dev);
+        }
 }
 
 static void rollback_registered(struct net_device *dev)
@@ -5074,6 +5092,8 @@ static void netdev_wait_allrefs(struct net_device *dev)
 
                         /* Rebroadcast unregister notification */
                         call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
+                        /* don't resend NETDEV_UNREGISTER_PERNET, _PERNET users
+                         * should have already handle it the first time */
 
                         if (test_bit(__LINK_STATE_LINKWATCH_PENDING,
                                      &dev->state)) {
@@ -5385,6 +5405,10 @@ EXPORT_SYMBOL(unregister_netdevice_queue);
  *      unregister_netdevice_many - unregister many devices
  *      @head: list of devices
  *
+ *      WARNING: Calling this modifies the given list
+ *      (in rollback_registered_many). It may change the order of the elements
+ *      in the list. However, you can assume it does not add or delete elements
+ *      to/from the list.
  */
 void unregister_netdevice_many(struct list_head *head)
 {
@@ -5504,6 +5528,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
            this device. They should clean all the things.
         */
         call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
+        call_netdevice_notifiers(NETDEV_UNREGISTER_PERNET, dev);
 
         /*
          *      Flush the unicast and multicast chains