Subject: [PATCH 1/1] NET: usb: Adding URB_ZERO_PACKET flag to usbnet.c
From: Elina Pasheva <epasheva@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Rory Filer <rfiler@xxxxxxxxxxxxxxxxxx>
---
drivers/net/usb/usbnet.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
--- a/drivers/net/usb/usbnet.c 2010-04-06 10:52:54.000000000 -0700
+++ b/drivers/net/usb/usbnet.c 2010-04-06 16:54:44.000000000 -0700
@@ -1068,12 +1068,15 @@ netdev_tx_t usbnet_start_xmit (struct sk
* 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) {
- urb->transfer_buffer_length++;
- if (skb_tailroom(skb)) {
- skb->data[skb->len] = 0;
- __skb_put(skb, 1);
- }
+ 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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