From: Daniele Palmas <dnlplm@xxxxxxxxx> [ Upstream commit eae7172f8141eb98e64e6e81acc9e9d5b2add127 ] usbnet creates network interfaces with min_mtu = 0 and max_mtu = ETH_MAX_MTU. These values are not modified by qmi_wwan when the network interface is created initially, allowing, for example, to set mtu greater than 1500. When a raw_ip switch is done (raw_ip set to 'Y', then set to 'N') the mtu values for the network interface are set through ether_setup, with min_mtu = ETH_MIN_MTU and max_mtu = ETH_DATA_LEN, not allowing anymore to set mtu greater than 1500 (error: mtu greater than device maximum). The patch restores the original min/max mtu values set by usbnet after a raw_ip switch. Signed-off-by: Daniele Palmas <dnlplm@xxxxxxxxx> Acked-by: Bjørn Mork <bjorn@xxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/net/usb/qmi_wwan.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/usb/qmi_wwan.c b/drivers/net/usb/qmi_wwan.c index 189715438328f..a8d5561afc7d4 100644 --- a/drivers/net/usb/qmi_wwan.c +++ b/drivers/net/usb/qmi_wwan.c @@ -274,6 +274,9 @@ static void qmi_wwan_netdev_setup(struct net_device *net) netdev_dbg(net, "mode: raw IP\n"); } else if (!net->header_ops) { /* don't bother if already set */ ether_setup(net); + /* Restoring min/max mtu values set originally by usbnet */ + net->min_mtu = 0; + net->max_mtu = ETH_MAX_MTU; clear_bit(EVENT_NO_IP_ALIGN, &dev->flags); netdev_dbg(net, "mode: Ethernet\n"); } -- 2.20.1