net/ethtool: Introduce link_ksettings API for virtual network devices

With the ethtool_virtdev_set_link_ksettings function in core/ethtool.c,
ibmveth, netvsc, and virtio now use the core's helper function.

Funtionality changes that pertain to ibmveth driver include:

  1. Changed the initial hardcoded link speed to 1GB.

  2. Added support for allowing a user to change the reported link
  speed via ethtool.

Functionality changes to the netvsc driver include:

  1. When netvsc_get_link_ksettings is called, it will defer to the VF
  device if it exists to pull accelerated networking values, otherwise
  pull default or user-defined values.

  2. Similarly, if netvsc_set_link_ksettings called and a VF device
  exists, the real values of speed and duplex are changed.

Signed-off-by: Cris Forno <cforno12@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/hyperv/netvsc_drv.c

@@ -1140,23 +1140,6 @@ out:
 	return ret;
 }
 
-static bool
-netvsc_validate_ethtool_ss_cmd(const struct ethtool_link_ksettings *cmd)
-{
-	struct ethtool_link_ksettings diff1 = *cmd;
-	struct ethtool_link_ksettings diff2 = {};
-
-	diff1.base.speed = 0;
-	diff1.base.duplex = 0;
-	/* advertising and cmd are usually set */
-	ethtool_link_ksettings_zero_link_mode(&diff1, advertising);
-	diff1.base.cmd = 0;
-	/* We set port to PORT_OTHER */
-	diff2.base.port = PORT_OTHER;
-
-	return !memcmp(&diff1, &diff2, sizeof(diff1));
-}
-
 static void netvsc_init_settings(struct net_device *dev)
 {
 	struct net_device_context *ndc = netdev_priv(dev);
@@ -1173,6 +1156,12 @@ static int netvsc_get_link_ksettings(struct net_device *dev,
 				     struct ethtool_link_ksettings *cmd)
 {
 	struct net_device_context *ndc = netdev_priv(dev);
+	struct net_device *vf_netdev;
+
+	vf_netdev = rtnl_dereference(ndc->vf_netdev);
+
+	if (vf_netdev)
+		return __ethtool_get_link_ksettings(vf_netdev, cmd);
 
 	cmd->base.speed = ndc->speed;
 	cmd->base.duplex = ndc->duplex;
@@ -1185,18 +1174,18 @@ static int netvsc_set_link_ksettings(struct net_device *dev,
 				     const struct ethtool_link_ksettings *cmd)
 {
 	struct net_device_context *ndc = netdev_priv(dev);
-	u32 speed;
+	struct net_device *vf_netdev = rtnl_dereference(ndc->vf_netdev);
 
-	speed = cmd->base.speed;
-	if (!ethtool_validate_speed(speed) ||
-	    !ethtool_validate_duplex(cmd->base.duplex) ||
-	    !netvsc_validate_ethtool_ss_cmd(cmd))
-		return -EINVAL;
+	if (vf_netdev) {
+		if (!vf_netdev->ethtool_ops->set_link_ksettings)
+			return -EOPNOTSUPP;
 
-	ndc->speed = speed;
-	ndc->duplex = cmd->base.duplex;
+		return vf_netdev->ethtool_ops->set_link_ksettings(vf_netdev,
+								  cmd);
+	}
 
-	return 0;
+	return ethtool_virtdev_set_link_ksettings(dev, cmd,
+						  &ndc->speed, &ndc->duplex);
 }
 
 static int netvsc_change_mtu(struct net_device *ndev, int mtu)