[PATCH net-next v2 2/5] net: thunderbolt: Allow changing MTU of the device

[Mika Westerberg <mika.westerberg@linux.intel.com>]

In some cases it is useful to be able to use different MTU than the
default one. Especially when dealing against non-Linux networking stack.
For this reason add possibility to change the MTU of the device.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
---
 drivers/net/thunderbolt/main.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/thunderbolt/main.c b/drivers/net/thunderbolt/main.c
index 57b226afeb84..20bac55a3e20 100644
--- a/drivers/net/thunderbolt/main.c
+++ b/drivers/net/thunderbolt/main.c
@@ -1257,12 +1257,23 @@ static void tbnet_get_stats64(struct net_device *dev,
 	stats->rx_missed_errors = net->stats.rx_missed_errors;
 }
 
+static int tbnet_change_mtu(struct net_device *dev, int new_mtu)
+{
+	/* Keep the MTU within supported range */
+	if (new_mtu < 68 || new_mtu > (TBNET_MAX_MTU - ETH_HLEN))
+		return -EINVAL;
+
+	dev->mtu = new_mtu;
+	return 0;
+}
+
 static const struct net_device_ops tbnet_netdev_ops = {
 	.ndo_open = tbnet_open,
 	.ndo_stop = tbnet_stop,
 	.ndo_start_xmit = tbnet_start_xmit,
 	.ndo_set_mac_address = eth_mac_addr,
 	.ndo_get_stats64 = tbnet_get_stats64,
+	.ndo_change_mtu	= tbnet_change_mtu,
 };
 
 static void tbnet_generate_mac(struct net_device *dev)
-- 
2.50.1