net: use core MTU range checking in USB NIC drivers

usbnet:
- Remove stale new_mtu <= 0 check in usbnet.c
- Set min_mtu = 0, max_mtu = 65535 (sub-drivers must set their own
  max_mtu and/or min_mtu as needed)

r8152:
- Set appropriate max_mtu for different variants (1500 or 9194)

lan78xx:
- Set max_mtu = 9000

asix_driver:
- max_mtu = 16384 for ax88178 variant

ax88179:
- max_mtu = 4088

cdc_ncm:
- max_mtu from hardware

cdc-phonet:
- min_mtu = 6, max_mtu = 65541

sierra_net:
- max_mtu = 1500, call usbnet_change_mtu directly
- sierra_net_change_mtu checked for MTU > 1500, then called
  usbnet_change_mtu, but if we set max_mtu to let the network core handle
  the range check, then we can simply call usbnet_change_mtu directly

smsc75xx:
- max_mtu = 9000

CC: netdev@vger.kernel.org
CC: Woojung Huh <woojung.huh@microchip.com>
CC: Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>
CC: Hayes Wang <hayeswang@realtek.com>
CC: Oliver Neukum <oneukum@suse.com>
CC: Steve Glendinning <steve.glendinning@shawell.net>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 3 deletions

diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index cce24950a0ab..7363cc5dd1bf 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -1026,9 +1026,6 @@ static int ax88178_change_mtu(struct net_device *net, int new_mtu)
 
 	netdev_dbg(dev->net, "ax88178_change_mtu() new_mtu=%d\n", new_mtu);
 
-	if (new_mtu <= 0 || ll_mtu > 16384)
-		return -EINVAL;
-
 	if ((ll_mtu % dev->maxpacket) == 0)
 		return -EDOM;
 
@@ -1081,6 +1078,7 @@ static int ax88178_bind(struct usbnet *dev, struct usb_interface *intf)
 
 	dev->net->netdev_ops = &ax88178_netdev_ops;
 	dev->net->ethtool_ops = &ax88178_ethtool_ops;
+	dev->net->max_mtu = 16384 - (dev->net->hard_header_len + 4);
 
 	/* Blink LEDS so users know driver saw dongle */
 	asix_sw_reset(dev, 0, 0);