[PATCH net-next v2 08/11] net: make NETDEV_UNREGISTER and instance lock more consistent

[Jakub Kicinski <kuba@kernel.org>]

The NETDEV_UNREGISTER notifier gets called under the ops lock
when device changes namespace but not during real unregistration.
Take it consistently, XSK tries to poke at netdev queue state
from this notifier.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 net/core/dev.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 652f2c6f5674..7bd8bd82f66f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1848,7 +1848,9 @@ static void call_netdevice_unregister_notifiers(struct notifier_block *nb,
 					dev);
 		call_netdevice_notifier(nb, NETDEV_DOWN, dev);
 	}
+	netdev_lock_ops(dev);
 	call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev);
+	netdev_unlock_ops(dev);
 }
 
 static int call_netdevice_register_net_notifiers(struct notifier_block *nb,
@@ -11174,8 +11176,11 @@ static struct net_device *netdev_wait_allrefs_any(struct list_head *list)
 			rtnl_lock();
 
 			/* Rebroadcast unregister notification */
-			list_for_each_entry(dev, list, todo_list)
+			list_for_each_entry(dev, list, todo_list) {
+				netdev_lock_ops(dev);
 				call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
+				netdev_unlock_ops(dev);
+			}
 
 			__rtnl_unlock();
 			rcu_barrier();
@@ -11966,7 +11971,9 @@ void unregister_netdevice_many_notify(struct list_head *head,
 		/* Notify protocols, that we are about to destroy
 		 * this device. They should clean all the things.
 		 */
+		netdev_lock_ops(dev);
 		call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
+		netdev_unlock_ops(dev);
 
 		if (!dev->rtnl_link_ops ||
 		    dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
-- 
2.49.0