net: usb: cdc_eem: fix mtu

BugLink: http://bugs.launchpad.net/bugs/981162

[ Upstream commit 78fb72f7936c01d5b426c03a691eca082b03f2b9 ]

Make CDC EEM recalculate the hard_mtu after adjusting the
hard_header_len.

Without this, usbnet adjusts the MTU down to 1494 bytes, and the host is
unable to receive standard 1500-byte frames from the device.

Tested with the Linux USB Ethernet gadget.

Cc: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Leann Ogasawara <leann.ogasawara@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/net/usb/cdc_eem.c b/drivers/net/usb/cdc_eem.c
index 882f53f..82d43b2 100644 (file)
--- a/drivers/net/usb/cdc_eem.c
+++ b/drivers/net/usb/cdc_eem.c
@@ -93,6 +93,7 @@ static int eem_bind(struct usbnet *dev, struct usb_interface *intf)
        /* no jumbogram (16K) support for now */
 
        dev->net->hard_header_len += EEM_HEAD + ETH_FCS_LEN;
+       dev->hard_mtu = dev->net->mtu + dev->net->hard_header_len;
 
        return 0;
 }