net: NETDEV_UNREGISTER_PERNET -> NETDEV_UNREGISTER_BATCH

The motivation for an additional notifier in batched netdevice
notification (rt_do_flush) only needs to be called once per batch not
once per namespace.

For further batching improvements I need a guarantee that the
netdevices are unregistered in order allowing me to unregister an all
of the network devices in a network namespace at the same time with
the guarantee that the loopback device is really and truly
unregistered last.

Additionally it appears that we moved the route cache flush after
the final synchronize_net, which seems wrong and there was no
explanation.  So I have restored the original location of the final
synchronize_net.

Cc: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index b0c3671d463ce6f7bd45d00e0d3ff6aebb9359af..fee6c2f68075c90fe77cea11138d627bd9efa4f5 100644 (file)
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -202,7 +202,7 @@ static inline int notifier_to_errno(int ret)
 #define NETDEV_BONDING_OLDTYPE  0x000E
 #define NETDEV_BONDING_NEWTYPE  0x000F
 #define NETDEV_POST_INIT       0x0010
-#define NETDEV_UNREGISTER_PERNET 0x0011
+#define NETDEV_UNREGISTER_BATCH 0x0011
 
 #define SYS_DOWN       0x0001  /* Notify of system down */
 #define SYS_RESTART    SYS_DOWN

diff --git a/include/net/route.h b/include/net/route.h
index cfb4c071a136b782f169cc780b447a2059adfb47..bce6dd68d27b4339f028d6d8f63dc6f3d5b88c52 100644 (file)
--- a/include/net/route.h
+++ b/include/net/route.h
@@ -108,6 +108,7 @@ extern int          ip_rt_init(void);
 extern void            ip_rt_redirect(__be32 old_gw, __be32 dst, __be32 new_gw,
                                       __be32 src, struct net_device *dev);
 extern void            rt_cache_flush(struct net *net, int how);
+extern void            rt_cache_flush_batch(void);
 extern int             __ip_route_output_key(struct net *, struct rtable **, const struct flowi *flp);
 extern int             ip_route_output_key(struct net *, struct rtable **, struct flowi *flp);
 extern int             ip_route_output_flow(struct net *, struct rtable **rp, struct flowi *flp, struct sock *sk, int flags);

diff --git a/net/core/dev.c b/net/core/dev.c
index 5d131c2f84cc374694a554d9b6245008d822d967..bb37ee1e09014393080973a92e7054e05ce637b8 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1353,7 +1353,7 @@ rollback:
                                nb->notifier_call(nb, NETDEV_DOWN, dev);
                        }
                        nb->notifier_call(nb, NETDEV_UNREGISTER, dev);
-                       nb->notifier_call(nb, NETDEV_UNREGISTER_PERNET, dev);
+                       nb->notifier_call(nb, NETDEV_UNREGISTER_BATCH, dev);
                }
        }
 
@@ -4771,8 +4771,7 @@ static void net_set_todo(struct net_device *dev)
 
 static void rollback_registered_many(struct list_head *head)
 {
-       struct net_device *dev, *aux, *fdev;
-       LIST_HEAD(pernet_list);
+       struct net_device *dev;
 
        BUG_ON(dev_boot_phase);
        ASSERT_RTNL();
@@ -4828,26 +4827,14 @@ static void rollback_registered_many(struct list_head *head)
                netdev_unregister_kobject(dev);
        }
 
-       synchronize_net();
+       /* Process any work delayed until the end of the batch */
+       dev = list_entry(head->next, struct net_device, unreg_list);
+       call_netdevice_notifiers(NETDEV_UNREGISTER_BATCH, dev);
 
-       list_for_each_entry_safe(dev, aux, head, unreg_list) {
-               int new_net = 1;
-               list_for_each_entry(fdev, &pernet_list, unreg_list) {
-                       if (net_eq(dev_net(dev), dev_net(fdev))) {
-                               new_net = 0;
-                               dev_put(dev);
-                               break;
-                       }
-               }
-               if (new_net)
-                       list_move(&dev->unreg_list, &pernet_list);
-       }
+       synchronize_net();
 
-       list_for_each_entry_safe(dev, aux, &pernet_list, unreg_list) {
-               call_netdevice_notifiers(NETDEV_UNREGISTER_PERNET, dev);
-               list_move(&dev->unreg_list, head);
+       list_for_each_entry(dev, head, unreg_list)
                dev_put(dev);
-       }
 }
 
 static void rollback_registered(struct net_device *dev)
@@ -5129,7 +5116,7 @@ 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
+                       /* don't resend NETDEV_UNREGISTER_BATCH, _BATCH users
                         * should have already handle it the first time */
 
                        if (test_bit(__LINK_STATE_LINKWATCH_PENDING,
@@ -5442,11 +5429,6 @@ 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)
 {
@@ -5555,7 +5537,7 @@ 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);
+       call_netdevice_notifiers(NETDEV_UNREGISTER_BATCH, dev);
 
        /*
         *      Flush the unicast and multicast chains

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 6c1e56aef1f4f15914473b91494d5d80739dbe2c..3b373a8b04738c48d1515ab078265f1e69629f73 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -959,9 +959,11 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo
                break;
        case NETDEV_CHANGEMTU:
        case NETDEV_CHANGE:
-       case NETDEV_UNREGISTER_PERNET:
                rt_cache_flush(dev_net(dev), 0);
                break;
+       case NETDEV_UNREGISTER_BATCH:
+               rt_cache_flush_batch();
+               break;
        }
        return NOTIFY_DONE;
 }

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 9889fbd964872abdaf3c2781811aec7a555cb7c5..90cdcfc32937358d1d12da545525437704cf4492 100644 (file)
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -900,6 +900,12 @@ void rt_cache_flush(struct net *net, int delay)
                rt_do_flush(!in_softirq());
 }
 
+/* Flush previous cache invalidated entries from the cache */
+void rt_cache_flush_batch(void)
+{
+       rt_do_flush(!in_softirq());
+}
+
 /*
  * We change rt_genid and let gc do the cleanup
  */