[PATCH AUTOSEL 4.9 155/251] net/af_iucv: always register net_device notifier

[Sasha Levin <sashal@kernel.org>]

From: Julian Wiedmann <jwi@linux.ibm.com>

[ Upstream commit 06996c1d4088a0d5f3e7789d7f96b4653cc947cc ]

Even when running as VM guest (ie pr_iucv != NULL), af_iucv can still
open HiperTransport-based connections. For robust operation these
connections require the af_iucv_netdev_notifier, so register it
unconditionally.

Also handle any error that register_netdevice_notifier() returns.

Fixes: 9fbd87d41392 ("af_iucv: handle netdev events")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/iucv/af_iucv.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/net/iucv/af_iucv.c b/net/iucv/af_iucv.c
index c2dfc32eb9f2..02e10deef5b4 100644
--- a/net/iucv/af_iucv.c
+++ b/net/iucv/af_iucv.c
@@ -2431,6 +2431,13 @@ static int afiucv_iucv_init(void)
 	return err;
 }
 
+static void afiucv_iucv_exit(void)
+{
+	device_unregister(af_iucv_dev);
+	driver_unregister(&af_iucv_driver);
+	pr_iucv->iucv_unregister(&af_iucv_handler, 0);
+}
+
 static int __init afiucv_init(void)
 {
 	int err;
@@ -2464,11 +2471,18 @@ static int __init afiucv_init(void)
 		err = afiucv_iucv_init();
 		if (err)
 			goto out_sock;
-	} else
-		register_netdevice_notifier(&afiucv_netdev_notifier);
+	}
+
+	err = register_netdevice_notifier(&afiucv_netdev_notifier);
+	if (err)
+		goto out_notifier;
+
 	dev_add_pack(&iucv_packet_type);
 	return 0;
 
+out_notifier:
+	if (pr_iucv)
+		afiucv_iucv_exit();
 out_sock:
 	sock_unregister(PF_IUCV);
 out_proto:
@@ -2482,12 +2496,11 @@ static int __init afiucv_init(void)
 static void __exit afiucv_exit(void)
 {
 	if (pr_iucv) {
-		device_unregister(af_iucv_dev);
-		driver_unregister(&af_iucv_driver);
-		pr_iucv->iucv_unregister(&af_iucv_handler, 0);
+		afiucv_iucv_exit();
 		symbol_put(iucv_if);
-	} else
-		unregister_netdevice_notifier(&afiucv_netdev_notifier);
+	}
+
+	unregister_netdevice_notifier(&afiucv_netdev_notifier);
 	dev_remove_pack(&iucv_packet_type);
 	sock_unregister(PF_IUCV);
 	proto_unregister(&iucv_proto);
-- 
2.20.1