net: remove the new_ifindex argument from dev_change_net_namespace

Here is only one place where we want to specify new_ifindex. In all
other cases, callers pass 0 as new_ifindex. It looks reasonable to add a
low-level function with new_ifindex and to convert
dev_change_net_namespace to a static inline wrapper.

Fixes: eeb85a14 ("net: Allow to specify ifindex when device is moved to another namespace")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/hyperv/netvsc_drv.c

@@ -2354,7 +2354,7 @@ static int netvsc_register_vf(struct net_device *vf_netdev)
 	 */
 	if (!net_eq(dev_net(ndev), dev_net(vf_netdev))) {
 		ret = dev_change_net_namespace(vf_netdev,
-					       dev_net(ndev), "eth%d", 0);
+					       dev_net(ndev), "eth%d");
 		if (ret)
 			netdev_err(vf_netdev,
 				   "could not move to same namespace as %s: %d\n",

include/linux/netdevice.h

@@ -4026,8 +4026,14 @@ void __dev_notify_flags(struct net_device *, unsigned int old_flags,
 int dev_change_name(struct net_device *, const char *);
 int dev_set_alias(struct net_device *, const char *, size_t);
 int dev_get_alias(const struct net_device *, char *, size_t);
-int dev_change_net_namespace(struct net_device *dev, struct net *net,
+int __dev_change_net_namespace(struct net_device *dev, struct net *net,
 			       const char *pat, int new_ifindex);
+static inline
+int dev_change_net_namespace(struct net_device *dev, struct net *net,
+			     const char *pat)
+{
+	return __dev_change_net_namespace(dev, net, pat, 0);
+}
 int __dev_set_mtu(struct net_device *, int);
 int dev_validate_mtu(struct net_device *dev, int mtu,
 		     struct netlink_ext_ack *extack);

net/core/dev.c

@@ -11062,7 +11062,7 @@ void unregister_netdev(struct net_device *dev)
 EXPORT_SYMBOL(unregister_netdev);
 
 /**
- *	dev_change_net_namespace - move device to different nethost namespace
+ *	__dev_change_net_namespace - move device to different nethost namespace
  *	@dev: device
  *	@net: network namespace
  *	@pat: If not NULL name pattern to try if the current device name
@@ -11077,7 +11077,7 @@ EXPORT_SYMBOL(unregister_netdev);
  *	Callers must hold the rtnl semaphore.
  */
 
-int dev_change_net_namespace(struct net_device *dev, struct net *net,
+int __dev_change_net_namespace(struct net_device *dev, struct net *net,
 			       const char *pat, int new_ifindex)
 {
 	struct net *net_old = dev_net(dev);
@@ -11202,7 +11202,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net,
 out:
 	return err;
 }
-EXPORT_SYMBOL_GPL(dev_change_net_namespace);
+EXPORT_SYMBOL_GPL(__dev_change_net_namespace);
 
 static int dev_cpu_dead(unsigned int oldcpu)
 {
@@ -11458,7 +11458,7 @@ static void __net_exit default_device_exit(struct net *net)
 		snprintf(fb_name, IFNAMSIZ, "dev%d", dev->ifindex);
 		if (__dev_get_by_name(&init_net, fb_name))
 			snprintf(fb_name, IFNAMSIZ, "dev%%d");
-		err = dev_change_net_namespace(dev, &init_net, fb_name, 0);
+		err = dev_change_net_namespace(dev, &init_net, fb_name);
 		if (err) {
 			pr_emerg("%s: failed to move %s to init_net: %d\n",
 				 __func__, dev->name, err);

net/core/rtnetlink.c

@@ -2619,7 +2619,7 @@ static int do_setlink(const struct sk_buff *skb,
 		else
 			new_ifindex = 0;
 
-		err = dev_change_net_namespace(dev, net, ifname, new_ifindex);
+		err = __dev_change_net_namespace(dev, net, ifname, new_ifindex);
 		put_net(net);
 		if (err)
 			goto errout;
@@ -3461,7 +3461,7 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
 	if (err < 0)
 		goto out_unregister;
 	if (link_net) {
-		err = dev_change_net_namespace(dev, dest_net, ifname, 0);
+		err = dev_change_net_namespace(dev, dest_net, ifname);
 		if (err < 0)
 			goto out_unregister;
 	}

net/ieee802154/core.c

@@ -205,7 +205,7 @@ int cfg802154_switch_netns(struct cfg802154_registered_device *rdev,
 		if (!wpan_dev->netdev)
 			continue;
 		wpan_dev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
-		err = dev_change_net_namespace(wpan_dev->netdev, net, "wpan%d", 0);
+		err = dev_change_net_namespace(wpan_dev->netdev, net, "wpan%d");
 		if (err)
 			break;
 		wpan_dev->netdev->features |= NETIF_F_NETNS_LOCAL;
@@ -222,7 +222,7 @@ int cfg802154_switch_netns(struct cfg802154_registered_device *rdev,
 				continue;
 			wpan_dev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
 			err = dev_change_net_namespace(wpan_dev->netdev, net,
-						       "wpan%d", 0);
+						       "wpan%d");
 			WARN_ON(err);
 			wpan_dev->netdev->features |= NETIF_F_NETNS_LOCAL;
 		}

net/wireless/core.c

@@ -165,7 +165,7 @@ int cfg80211_switch_netns(struct cfg80211_registered_device *rdev,
 		if (!wdev->netdev)
 			continue;
 		wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
-		err = dev_change_net_namespace(wdev->netdev, net, "wlan%d", 0);
+		err = dev_change_net_namespace(wdev->netdev, net, "wlan%d");
 		if (err)
 			break;
 		wdev->netdev->features |= NETIF_F_NETNS_LOCAL;
@@ -182,7 +182,7 @@ int cfg80211_switch_netns(struct cfg80211_registered_device *rdev,
 				continue;
 			wdev->netdev->features &= ~NETIF_F_NETNS_LOCAL;
 			err = dev_change_net_namespace(wdev->netdev, net,
-							"wlan%d", 0);
+							"wlan%d");
 			WARN_ON(err);
 			wdev->netdev->features |= NETIF_F_NETNS_LOCAL;
 		}