Commit b4d562e3 authored Apr 06, 2010 by Elina Pasheva Committed by David S. Miller Apr 06, 2010

NET: usb: Adding URB_ZERO_PACKET flag to usbnet.c



This patch adds setting of the urb transfer flag URB_ZERO_PACKET  before
submitting an urb for drivers that have requested it (by advertising flag
FLAG_SEND_ZLP).
The modification is in usbnet.c function usbnet_start_xmit().
This patch only adds the zero length flag.
A subsequent patch will address the buggy code we found when devices do not
advertise FLAG_SEND_ZLP in which case there is a possibility of transferring
packets with non-deterministic length.

This patch has been tested on kernel-2.6.34-rc3.
This patch has been checked against net-2.6 tree.
Signed-off-by: Elina Pasheva <epasheva@sierrawireless.com>
Signed-off-by: Rory Filer <rfiler@sierrawireless.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 17a328ca

drivers/net/usb/usbnet.c

+9 −6

Original line number	Diff line number	Diff line
		@@ -1068,12 +1068,15 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb,
		* NOTE: strictly conforming cdc-ether devices should expect
		* the ZLP here, but ignore the one-byte packet.
		*/
		if (!(info->flags & FLAG_SEND_ZLP) && (length % dev->maxpacket) == 0) {
		if (length % dev->maxpacket == 0) {
		if (!(info->flags & FLAG_SEND_ZLP)) {
		urb->transfer_buffer_length++;
		if (skb_tailroom(skb)) {
		skb->data[skb->len] = 0;
		__skb_put(skb, 1);
		}
		} else
		urb->transfer_flags \|= URB_ZERO_PACKET;
		}

		spin_lock_irqsave(&dev->txq.lock, flags);

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