[RTNETLINK]: rtnl_link API simplification

All drivers need to unregister their devices in the module unload function.
While doing so they must hold the rtnl and atomically unregister the
rtnl_link ops as well. This makes the rtnl_link_unregister function that
takes the rtnl itself completely useless.

Provide default newlink/dellink functions, make __rtnl_link_unregister and
rtnl_link_unregister unregister all devices with matching rtnl_link_ops and
change the existing users to take advantage of that.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 14 insertions, 4 deletions

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 54c17e4cd28f..7b6b16396745 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -270,6 +270,9 @@ static LIST_HEAD(link_ops);
  */
 int __rtnl_link_register(struct rtnl_link_ops *ops)
 {
+        if (!ops->dellink)
+                ops->dellink = unregister_netdevice;
+
         list_add_tail(&ops->list, &link_ops);
         return 0;
 }
@@ -298,12 +301,16 @@ EXPORT_SYMBOL_GPL(rtnl_link_register);
  * __rtnl_link_unregister - Unregister rtnl_link_ops from rtnetlink.
  * @ops: struct rtnl_link_ops * to unregister
  *
- * The caller must hold the rtnl_mutex. This function should be used
- * by drivers that unregister devices during module unloading. It must
- * be called after unregistering the devices.
+ * The caller must hold the rtnl_mutex.
  */
 void __rtnl_link_unregister(struct rtnl_link_ops *ops)
 {
+        struct net_device *dev, *n;
+
+        for_each_netdev_safe(dev, n) {
+                if (dev->rtnl_link_ops == ops)
+                        ops->dellink(dev);
+        }
         list_del(&ops->list);
 }
 
@@ -1067,7 +1074,10 @@ replay:
                 if (tb[IFLA_LINKMODE])
                         dev->link_mode = nla_get_u8(tb[IFLA_LINKMODE]);
 
-                err = ops->newlink(dev, tb, data);
+                if (ops->newlink)
+                        err = ops->newlink(dev, tb, data);
+                else
+                        err = register_netdevice(dev);
 err_free:
                 if (err < 0)
                         free_netdev(dev);