From: Jiri Pirko <jiri@mellanox.com>
Date: Mon, 30 Sep 2019 10:15:09 +0200
Subject: net: push loops and nb calls into helper functions
Patch-mainline: v5.5-rc1
Git-commit: afa0df5998131153ec3036f41e76ece33bf1334f
References: bsc#1154353

Push iterations over net namespaces and netdevices from
register_netdevice_notifier() and unregister_netdevice_notifier()
into helper functions. Along with that introduce continue_reverse macros
to make the code a bit nicer allowing to get rid of "last" marks.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 include/linux/netdevice.h   |    3 +
 include/net/net_namespace.h |    3 -
 net/core/dev.c              |   89 ++++++++++++++++++++++++++++++--------------
 3 files changed, 66 insertions(+), 29 deletions(-)

--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2567,6 +2567,9 @@ extern rwlock_t				dev_base_lock;		/* De
 		list_for_each_entry_safe(d, n, &(net)->dev_base_head, dev_list)
 #define for_each_netdev_continue(net, d)		\
 		list_for_each_entry_continue(d, &(net)->dev_base_head, dev_list)
+#define for_each_netdev_continue_reverse(net, d)		\
+		list_for_each_entry_continue_reverse(d, &(net)->dev_base_head, \
+						     dev_list)
 #define for_each_netdev_continue_rcu(net, d)		\
 	list_for_each_entry_continue_rcu(d, &(net)->dev_base_head, dev_list)
 #define for_each_netdev_in_bond_rcu(bond, slave)	\
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -323,7 +323,8 @@ static inline struct net *read_pnet(cons
 /* Protected by net_rwsem */
 #define for_each_net(VAR)				\
 	list_for_each_entry(VAR, &net_namespace_list, list)
-
+#define for_each_net_continue_reverse(VAR)		\
+	list_for_each_entry_continue_reverse(VAR, &net_namespace_list, list)
 #define for_each_net_rcu(VAR)				\
 	list_for_each_entry_rcu(VAR, &net_namespace_list, list)
 
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1644,6 +1644,62 @@ static int call_netdevice_notifier(struc
 	return nb->notifier_call(nb, val, &info);
 }
 
+static int call_netdevice_register_notifiers(struct notifier_block *nb,
+					     struct net_device *dev)
+{
+	int err;
+
+	err = call_netdevice_notifier(nb, NETDEV_REGISTER, dev);
+	err = notifier_to_errno(err);
+	if (err)
+		return err;
+
+	if (!(dev->flags & IFF_UP))
+		return 0;
+
+	call_netdevice_notifier(nb, NETDEV_UP, dev);
+	return 0;
+}
+
+static void call_netdevice_unregister_notifiers(struct notifier_block *nb,
+						struct net_device *dev)
+{
+	if (dev->flags & IFF_UP) {
+		call_netdevice_notifier(nb, NETDEV_GOING_DOWN,
+					dev);
+		call_netdevice_notifier(nb, NETDEV_DOWN, dev);
+	}
+	call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev);
+}
+
+static int call_netdevice_register_net_notifiers(struct notifier_block *nb,
+						 struct net *net)
+{
+	struct net_device *dev;
+	int err;
+
+	for_each_netdev(net, dev) {
+		err = call_netdevice_register_notifiers(nb, dev);
+		if (err)
+			goto rollback;
+	}
+	return 0;
+
+rollback:
+	for_each_netdev_continue_reverse(net, dev)
+		call_netdevice_unregister_notifiers(nb, dev);
+	return err;
+}
+
+static void call_netdevice_unregister_net_notifiers(struct notifier_block *nb,
+						    struct net *net)
+{
+	struct net_device *dev;
+
+	for_each_netdev(net, dev)
+		call_netdevice_unregister_notifiers(nb, dev);
+}
+
 static int dev_boot_phase = 1;
 
 /**
@@ -1662,8 +1718,6 @@ static int dev_boot_phase = 1;
 
 int register_netdevice_notifier(struct notifier_block *nb)
 {
-	struct net_device *dev;
-	struct net_device *last;
 	struct net *net;
 	int err;
 
@@ -1676,17 +1730,9 @@ int register_netdevice_notifier(struct n
 	if (dev_boot_phase)
 		goto unlock;
 	for_each_net(net) {
-		for_each_netdev(net, dev) {
-			err = call_netdevice_notifier(nb, NETDEV_REGISTER, dev);
-			err = notifier_to_errno(err);
-			if (err)
-				goto rollback;
-
-			if (!(dev->flags & IFF_UP))
-				continue;
-
-			call_netdevice_notifier(nb, NETDEV_UP, dev);
-		}
+		err = call_netdevice_register_net_notifiers(nb, net);
+		if (err)
+			goto rollback;
 	}
 
 unlock:
@@ -1695,22 +1741,9 @@ unlock:
 	return err;
 
 rollback:
-	last = dev;
-	for_each_net(net) {
-		for_each_netdev(net, dev) {
-			if (dev == last)
-				goto outroll;
-
-			if (dev->flags & IFF_UP) {
-				call_netdevice_notifier(nb, NETDEV_GOING_DOWN,
-							dev);
-				call_netdevice_notifier(nb, NETDEV_DOWN, dev);
-			}
-			call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev);
-		}
-	}
+	for_each_net_continue_reverse(net)
+		call_netdevice_unregister_net_notifiers(nb, net);
 
-outroll:
 	raw_notifier_chain_unregister(&netdev_chain, nb);
 	goto unlock;
 }