net: usb: smsc75xx: fix mtu

[ Upstream commit a99ff7d0123b19ecad3b589480b6542716ab6b52 ]

Make smsc75xx recalculate the hard_mtu after adjusting the
hard_header_len.

Without this, usbnet adjusts the MTU down to 1492 bytes, and the host is
unable to receive standard 1500-byte frames from the device.

Inspired by same fix on cdc_eem 78fb72f7936c01d5b426c03a691eca082b03f2b9.

Tested on ARM/Omap3 with EVB-LAN7500-LC.

Signed-off-by: Stephane Fillod <fillods@users.sf.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/usb/smsc75xx.c b/drivers/net/usb/smsc75xx.c
index 15b3d68..de0de3e 100644 (file)
--- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c
@@ -1049,6 +1049,7 @@ static int smsc75xx_bind(struct usbnet *dev, struct usb_interface *intf)
        dev->net->ethtool_ops = &smsc75xx_ethtool_ops;
        dev->net->flags |= IFF_MULTICAST;
        dev->net->hard_header_len += SMSC75XX_TX_OVERHEAD;
+       dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;
        return 0;
 }