net: switchdev: Change notifier chain to be atomic

In order to use the switchdev notifier chain for FDB sync with the
device it has to be changed to atomic. The is done because the bridge
can learn new FDBs in atomic context.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/switchdev/switchdev.c

@@ -571,24 +571,17 @@ int switchdev_port_obj_dump(struct net_device *dev, struct switchdev_obj *obj,
 }
 EXPORT_SYMBOL_GPL(switchdev_port_obj_dump);
 
-static RAW_NOTIFIER_HEAD(switchdev_notif_chain);
+static ATOMIC_NOTIFIER_HEAD(switchdev_notif_chain);
 
 /**
  *	register_switchdev_notifier - Register notifier
  *	@nb: notifier_block
  *
- *	Register switch device notifier. This should be used by code
- *	which needs to monitor events happening in particular device.
- *	Return values are same as for atomic_notifier_chain_register().
+ *	Register switch device notifier.
  */
 int register_switchdev_notifier(struct notifier_block *nb)
 {
-	int err;
-
-	rtnl_lock();
-	err = raw_notifier_chain_register(&switchdev_notif_chain, nb);
-	rtnl_unlock();
-	return err;
+	return atomic_notifier_chain_register(&switchdev_notif_chain, nb);
 }
 EXPORT_SYMBOL_GPL(register_switchdev_notifier);
 
@@ -597,16 +590,10 @@ EXPORT_SYMBOL_GPL(register_switchdev_notifier);
  *	@nb: notifier_block
  *
  *	Unregister switch device notifier.
- *	Return values are same as for atomic_notifier_chain_unregister().
  */
 int unregister_switchdev_notifier(struct notifier_block *nb)
 {
-	int err;
-
-	rtnl_lock();
-	err = raw_notifier_chain_unregister(&switchdev_notif_chain, nb);
-	rtnl_unlock();
-	return err;
+	return atomic_notifier_chain_unregister(&switchdev_notif_chain, nb);
 }
 EXPORT_SYMBOL_GPL(unregister_switchdev_notifier);
 
@@ -616,18 +603,13 @@ EXPORT_SYMBOL_GPL(unregister_switchdev_notifier);
  *	@dev: port device
  *	@info: notifier information data
  *
- *	Call all network notifier blocks. This should be called by driver
- *	when it needs to propagate hardware event.
- *	Return values are same as for atomic_notifier_call_chain().
- *	rtnl_lock must be held.
+ *	Call all network notifier blocks.
  */
 int call_switchdev_notifiers(unsigned long val, struct net_device *dev,
 			     struct switchdev_notifier_info *info)
 {
-	ASSERT_RTNL();
-
 	info->dev = dev;
-	return raw_notifier_call_chain(&switchdev_notif_chain, val, info);
+	return atomic_notifier_call_chain(&switchdev_notif_chain, val, info);
 }
 EXPORT_SYMBOL_GPL(call_switchdev_notifiers);