net: vlan: convert to ndo_hwtstamp_get() / ndo_hwtstamp_set()

8021q is one of the stackable net devices which pass the hardware
timestamping ops to the real device through ndo_eth_ioctl(). This
prevents converting any device driver to the new hwtimestamping API
without regressions.

Remove that limitation in the vlan driver by using the newly introduced
helpers for timestamping through lower devices, that handle both the new
and the old driver API.

Signed-off-by: Maxim Georgiev <glipus@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20230801142824.1772134-4-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/8021q/vlan_dev.c

@@ -354,6 +354,26 @@ static int vlan_dev_set_mac_address(struct net_device *dev, void *p)
 	return 0;
 }
 
+static int vlan_hwtstamp_get(struct net_device *dev,
+			     struct kernel_hwtstamp_config *cfg)
+{
+	struct net_device *real_dev = vlan_dev_priv(dev)->real_dev;
+
+	return generic_hwtstamp_get_lower(real_dev, cfg);
+}
+
+static int vlan_hwtstamp_set(struct net_device *dev,
+			     struct kernel_hwtstamp_config *cfg,
+			     struct netlink_ext_ack *extack)
+{
+	struct net_device *real_dev = vlan_dev_priv(dev)->real_dev;
+
+	if (!net_eq(dev_net(dev), dev_net(real_dev)))
+		return -EOPNOTSUPP;
+
+	return generic_hwtstamp_set_lower(real_dev, cfg, extack);
+}
+
 static int vlan_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 {
 	struct net_device *real_dev = vlan_dev_priv(dev)->real_dev;
@@ -365,14 +385,9 @@ static int vlan_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 	ifrr.ifr_ifru = ifr->ifr_ifru;
 
 	switch (cmd) {
-	case SIOCSHWTSTAMP:
-		if (!net_eq(dev_net(dev), dev_net(real_dev)))
-			break;
-		fallthrough;
 	case SIOCGMIIPHY:
 	case SIOCGMIIREG:
 	case SIOCSMIIREG:
-	case SIOCGHWTSTAMP:
 		if (netif_device_present(real_dev) && ops->ndo_eth_ioctl)
 			err = ops->ndo_eth_ioctl(real_dev, &ifrr, cmd);
 		break;
@@ -1081,6 +1096,8 @@ static const struct net_device_ops vlan_netdev_ops = {
 	.ndo_fix_features	= vlan_dev_fix_features,
 	.ndo_get_iflink		= vlan_dev_get_iflink,
 	.ndo_fill_forward_path	= vlan_dev_fill_forward_path,
+	.ndo_hwtstamp_get	= vlan_hwtstamp_get,
+	.ndo_hwtstamp_set	= vlan_hwtstamp_set,
 };
 
 static void vlan_dev_free(struct net_device *dev)