Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[karo-tx-linux.git] / net / core / dev.c

diff --git a/net/core/dev.c b/net/core/dev.c
index 81340ed7f0f42f3dfe3ff17041841ba2125b3d95..c25db20a424662600e93bf856aa6a61c81508b8e 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5428,10 +5428,12 @@ static int dev_new_index(struct net *net)
 
 /* Delayed registration/unregisteration */
 static LIST_HEAD(net_todo_list);
+static DECLARE_WAIT_QUEUE_HEAD(netdev_unregistering_wq);
 
 static void net_set_todo(struct net_device *dev)
 {
        list_add_tail(&dev->todo_list, &net_todo_list);
+       dev_net(dev)->dev_unreg_count++;
 }
 
 static void rollback_registered_many(struct list_head *head)
@@ -6099,6 +6101,12 @@ void netdev_run_todo(void)
                if (dev->destructor)
                        dev->destructor(dev);
 
+               /* Report a network device has been unregistered */
+               rtnl_lock();
+               dev_net(dev)->dev_unreg_count--;
+               __rtnl_unlock();
+               wake_up(&netdev_unregistering_wq);
+
                /* Free network device */
                kobject_put(&dev->dev.kobj);
        }
@@ -6786,6 +6794,34 @@ static void __net_exit default_device_exit(struct net *net)
        rtnl_unlock();
 }
 
+static void __net_exit rtnl_lock_unregistering(struct list_head *net_list)
+{
+       /* Return with the rtnl_lock held when there are no network
+        * devices unregistering in any network namespace in net_list.
+        */
+       struct net *net;
+       bool unregistering;
+       DEFINE_WAIT(wait);
+
+       for (;;) {
+               prepare_to_wait(&netdev_unregistering_wq, &wait,
+                               TASK_UNINTERRUPTIBLE);
+               unregistering = false;
+               rtnl_lock();
+               list_for_each_entry(net, net_list, exit_list) {
+                       if (net->dev_unreg_count > 0) {
+                               unregistering = true;
+                               break;
+                       }
+               }
+               if (!unregistering)
+                       break;
+               __rtnl_unlock();
+               schedule();
+       }
+       finish_wait(&netdev_unregistering_wq, &wait);
+}
+
 static void __net_exit default_device_exit_batch(struct list_head *net_list)
 {
        /* At exit all network devices most be removed from a network
@@ -6797,7 +6833,18 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
        struct net *net;
        LIST_HEAD(dev_kill_list);
 
-       rtnl_lock();
+       /* To prevent network device cleanup code from dereferencing
+        * loopback devices or network devices that have been freed
+        * wait here for all pending unregistrations to complete,
+        * before unregistring the loopback device and allowing the
+        * network namespace be freed.
+        *
+        * The netdev todo list containing all network devices
+        * unregistrations that happen in default_device_exit_batch
+        * will run in the rtnl_unlock() at the end of
+        * default_device_exit_batch.
+        */
+       rtnl_lock_unregistering(net_list);
        list_for_each_entry(net, net_list, exit_list) {
                for_each_netdev_reverse(net, dev) {
                        if (dev->rtnl_link_ops)