dev: introduce dev_get_iflink()

The goal of this patch is to prepare the removal of the iflink field. It
introduces a new ndo function, which will be implemented by virtual interfaces.

There is no functional change into this patch. All readers of iflink field
now call dev_get_iflink().

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 34 insertions, 9 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index 65492b0354c0..77172d085760 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -660,6 +660,23 @@ __setup("netdev=", netdev_boot_setup);
 *******************************************************************************/
 
 /**
+ *	dev_get_iflink	- get 'iflink' value of a interface
+ *	@dev: targeted interface
+ *
+ *	Indicates the ifindex the interface is linked to.
+ *	Physical interfaces have the same 'ifindex' and 'iflink' values.
+ */
+
+int dev_get_iflink(const struct net_device *dev)
+{
+	if (dev->netdev_ops && dev->netdev_ops->ndo_get_iflink)
+		return dev->netdev_ops->ndo_get_iflink(dev);
+
+	return dev->iflink;
+}
+EXPORT_SYMBOL(dev_get_iflink);
+
+/**
  *	__dev_get_by_name	- find a device by its name
  *	@net: the applicable net namespace
  *	@name: name to find
@@ -6345,7 +6362,7 @@ int register_netdevice(struct net_device *dev)
 	else if (__dev_get_by_index(net, dev->ifindex))
 		goto err_uninit;
 
-	if (dev->iflink == -1)
+	if (dev_get_iflink(dev) == -1)
 		dev->iflink = dev->ifindex;
 
 	/* Transfer changeable features to wanted_features and enable
@@ -7061,7 +7078,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char
 
 	/* If there is an ifindex conflict assign a new one */
 	if (__dev_get_by_index(net, dev->ifindex)) {
-		int iflink = (dev->iflink == dev->ifindex);
+		int iflink = (dev_get_iflink(dev) == dev->ifindex);
 		dev->ifindex = dev_new_index(net);
 		if (iflink)
 			dev->iflink = dev->ifindex;
diff --git a/net/core/link_watch.c b/net/core/link_watch.c
index 49a9e3e06c08..982861607f88 100644
--- a/net/core/link_watch.c
+++ b/net/core/link_watch.c
@@ -40,7 +40,7 @@ static DEFINE_SPINLOCK(lweventlist_lock);
 static unsigned char default_operstate(const struct net_device *dev)
 {
 	if (!netif_carrier_ok(dev))
-		return (dev->ifindex != dev->iflink ?
+		return (dev->ifindex != dev_get_iflink(dev) ?
 			IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN);
 
 	if (netif_dormant(dev))
@@ -89,7 +89,7 @@ static bool linkwatch_urgent_event(struct net_device *dev)
 	if (!netif_running(dev))
 		return false;
 
-	if (dev->ifindex != dev->iflink)
+	if (dev->ifindex != dev_get_iflink(dev))
 		return true;
 
 	if (dev->priv_flags & IFF_TEAM_PORT)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index cc5cf689809c..4238d6da5c60 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -109,11 +109,19 @@ NETDEVICE_SHOW_RO(dev_id, fmt_hex);
 NETDEVICE_SHOW_RO(dev_port, fmt_dec);
 NETDEVICE_SHOW_RO(addr_assign_type, fmt_dec);
 NETDEVICE_SHOW_RO(addr_len, fmt_dec);
-NETDEVICE_SHOW_RO(iflink, fmt_dec);
 NETDEVICE_SHOW_RO(ifindex, fmt_dec);
 NETDEVICE_SHOW_RO(type, fmt_dec);
 NETDEVICE_SHOW_RO(link_mode, fmt_dec);
 
+static ssize_t iflink_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct net_device *ndev = to_net_dev(dev);
+
+	return sprintf(buf, fmt_dec, dev_get_iflink(ndev));
+}
+static DEVICE_ATTR_RO(iflink);
+
 static ssize_t format_name_assign_type(const struct net_device *dev, char *buf)
 {
 	return sprintf(buf, fmt_dec, dev->name_assign_type);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index b96ac2109c82..ee0186cdd5cf 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1055,8 +1055,8 @@ static int rtnl_fill_ifinfo(struct sk_buff *skb, struct net_device *dev,
 #ifdef CONFIG_RPS
 	    nla_put_u32(skb, IFLA_NUM_RX_QUEUES, dev->num_rx_queues) ||
 #endif
-	    (dev->ifindex != dev->iflink &&
-	     nla_put_u32(skb, IFLA_LINK, dev->iflink)) ||
+	    (dev->ifindex != dev_get_iflink(dev) &&
+	     nla_put_u32(skb, IFLA_LINK, dev_get_iflink(dev))) ||
 	    (upper_dev &&
 	     nla_put_u32(skb, IFLA_MASTER, upper_dev->ifindex)) ||
 	    nla_put_u8(skb, IFLA_CARRIER, netif_carrier_ok(dev)) ||
@@ -2863,8 +2863,8 @@ int ndo_dflt_bridge_getlink(struct sk_buff *skb, u32 pid, u32 seq,
 	     nla_put_u32(skb, IFLA_MASTER, br_dev->ifindex)) ||
 	    (dev->addr_len &&
 	     nla_put(skb, IFLA_ADDRESS, dev->addr_len, dev->dev_addr)) ||
-	    (dev->ifindex != dev->iflink &&
-	     nla_put_u32(skb, IFLA_LINK, dev->iflink)))
+	    (dev->ifindex != dev_get_iflink(dev) &&
+	     nla_put_u32(skb, IFLA_LINK, dev_get_iflink(dev))))
 		goto nla_put_failure;
 
 	br_afspec = nla_nest_start(skb, IFLA_AF_SPEC);