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

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

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d6417464dc665867a6db5829cf7520b8c207f57a..f31268dbc0d1b983e10277666b2788f6fb03ac13 100644 (file)
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -353,15 +353,46 @@ void __rtnl_link_unregister(struct rtnl_link_ops *ops)
 }
 EXPORT_SYMBOL_GPL(__rtnl_link_unregister);
 
+/* Return with the rtnl_lock held when there are no network
+ * devices unregistering in any network namespace.
+ */
+static void rtnl_lock_unregistering_all(void)
+{
+       struct net *net;
+       bool unregistering;
+       DEFINE_WAIT(wait);
+
+       for (;;) {
+               prepare_to_wait(&netdev_unregistering_wq, &wait,
+                               TASK_UNINTERRUPTIBLE);
+               unregistering = false;
+               rtnl_lock();
+               for_each_net(net) {
+                       if (net->dev_unreg_count > 0) {
+                               unregistering = true;
+                               break;
+                       }
+               }
+               if (!unregistering)
+                       break;
+               __rtnl_unlock();
+               schedule();
+       }
+       finish_wait(&netdev_unregistering_wq, &wait);
+}
+
 /**
  * rtnl_link_unregister - Unregister rtnl_link_ops from rtnetlink.
  * @ops: struct rtnl_link_ops * to unregister
  */
 void rtnl_link_unregister(struct rtnl_link_ops *ops)
 {
-       rtnl_lock();
+       /* Close the race with cleanup_net() */
+       mutex_lock(&net_mutex);
+       rtnl_lock_unregistering_all();
        __rtnl_link_unregister(ops);
        rtnl_unlock();
+       mutex_unlock(&net_mutex);
 }
 EXPORT_SYMBOL_GPL(rtnl_link_unregister);