From mboxrd@z Thu Jan 1 00:00:00 1970 From: Elina Pasheva Subject: [PATCH 1/1] NET: usb: Adding URB_ZERO_PACKET flag to usbnet.c Date: Tue, 6 Apr 2010 17:23:07 -0700 Message-ID: <1270599787.8900.8.camel@Linuxdev4-laptop> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: , , , To: Return-path: Received: from carmd-sa02.sierrawireless.com ([208.81.121.46]:49373 "EHLO carmd-sa02.sierrawireless.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932229Ab0DGAXN (ORCPT ); Tue, 6 Apr 2010 20:23:13 -0400 Sender: netdev-owner@vger.kernel.org List-ID: Subject: [PATCH 1/1] NET: usb: Adding URB_ZERO_PACKET flag to usbnet.c From: Elina Pasheva 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 Signed-off-by: Rory Filer --- 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);