usbnet: Zero padding byte if there is tail room in skb

Usbnet adds a padding byte if a 0 byte USB packet would be sent. Zero
padding byte if there is tail room in skb.

Signed-of-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>

Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 6 insertions, 3 deletions

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 5b16d9a1269a..a12f576391cf 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -953,11 +953,14 @@ static int usbnet_start_xmit (struct sk_buff *skb, struct net_device *net)
         /* don't assume the hardware handles USB_ZERO_PACKET
          * NOTE:  strictly conforming cdc-ether devices should expect
          * the ZLP here, but ignore the one-byte packet.
-         *
-         * FIXME zero that byte, if it doesn't require a new skb.
          */
-        if ((length % dev->maxpacket) == 0)
+        if ((length % dev->maxpacket) == 0) {
                 urb->transfer_buffer_length++;
+                if (skb_tailroom(skb)) {
+                        skb->data[skb->len] = 0;
+                        __skb_put(skb, 1);
+                }
+        }
 
         spin_lock_irqsave (&dev->txq.lock, flags);