act_mirred: Fix mirred_init_module error handling

stable inclusion
from linux-4.19.99
commit 5c1b003d22aba2ff0853f0e775c3cfa7e42522cd

--------------------------------

[ Upstream commit 11c9a7d3 ]

If tcf_register_action failed, mirred_device_notifier
should be unregistered.

Fixes: 3b87956e ("net sched: fix race in mirred device removal")
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NLi Aichun <liaichun@huawei.com>
Reviewed-by: Nguodeqing <geffrey.guo@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

net/sched/act_mirred.c

@@ -447,7 +447,11 @@ static int __init mirred_init_module(void)
 		return err;
 
 	pr_info("Mirror/redirect action on\n");
-	return tcf_register_action(&act_mirred_ops, &mirred_net_ops);
+	err = tcf_register_action(&act_mirred_ops, &mirred_net_ops);
+	if (err)
+		unregister_netdevice_notifier(&mirred_device_notifier);
+
+	return err;
 }
 
 static void __exit mirred_cleanup_module(void)