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>
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 877c951..7141817 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -740,10 +740,6 @@ static void cdc_ncm_free(struct cdc_ncm_ctx *ctx)
int cdc_ncm_change_mtu(struct net_device *net, int new_mtu)
{
struct usbnet *dev = netdev_priv(net);
- int maxmtu = cdc_ncm_max_dgram_size(dev) - cdc_ncm_eth_hlen(dev);
-
- if (new_mtu <= 0 || new_mtu > maxmtu)
- return -EINVAL;
net->mtu = new_mtu;
cdc_ncm_set_dgram_size(dev, new_mtu + cdc_ncm_eth_hlen(dev));
@@ -909,6 +905,7 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
/* must handle MTU changes */
dev->net->netdev_ops = &cdc_ncm_netdev_ops;
+ dev->net->max_mtu = cdc_ncm_max_dgram_size(dev) - cdc_ncm_eth_hlen(dev);
return 0;
