Commit 60e453a9 authored by Ming Lei's avatar Ming Lei Committed by David S. Miller
Browse files

USBNET: fix handling padding packet 



Commit 638c5115(USBNET: support DMA SG) introduces DMA SG
if the usb host controller is capable of building packet from
discontinuous buffers, but missed handling padding packet when
building DMA SG.

This patch attachs the pre-allocated padding packet at the
end of the sg list, so padding packet can be sent to device
if drivers require that.

Reported-by: default avatarDavid Laight <David.Laight@aculab.com>
Acked-by: default avatarOliver Neukum <oliver@neukum.org>
Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 66451615

drivers/net/usb/usbnet.c

+21 −6
Original line number Diff line number Diff line
@@ -1241,7 +1241,9 @@ static int build_dma_sg(const struct sk_buff *skb, struct urb *urb) 
	if (num_sgs == 1)

		return 0;



	urb->sg = kmalloc(num_sgs * sizeof(struct scatterlist), GFP_ATOMIC);

	/* reserve one for zero packet */

	urb->sg = kmalloc((num_sgs + 1) * sizeof(struct scatterlist),

			  GFP_ATOMIC);

	if (!urb->sg)

		return -ENOMEM;
@@ -1305,7 +1307,7 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb, 
		if (build_dma_sg(skb, urb) < 0)

			goto drop;

	}

	entry->length = length = urb->transfer_buffer_length;

	length = urb->transfer_buffer_length;



	/* don't assume the hardware handles USB_ZERO_PACKET

	 * NOTE:  strictly conforming cdc-ether devices should expect
@@ -1317,15 +1319,18 @@ netdev_tx_t usbnet_start_xmit (struct sk_buff *skb, 
	if (length % dev->maxpacket == 0) {

		if (!(info->flags & FLAG_SEND_ZLP)) {

			if (!(info->flags & FLAG_MULTI_PACKET)) {

				urb->transfer_buffer_length++;

				if (skb_tailroom(skb)) {

				length++;

				if (skb_tailroom(skb) && !urb->num_sgs) {

					skb->data[skb->len] = 0;

					__skb_put(skb, 1);

				}

				} else if (urb->num_sgs)

					sg_set_buf(&urb->sg[urb->num_sgs++],

							dev->padding_pkt, 1);

			}

		} else

			urb->transfer_flags |= URB_ZERO_PACKET;

	}

	entry->length = urb->transfer_buffer_length = length;



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

	retval = usb_autopm_get_interface_async(dev->intf);
@@ -1509,6 +1514,7 @@ void usbnet_disconnect (struct usb_interface *intf) 


	usb_kill_urb(dev->interrupt);

	usb_free_urb(dev->interrupt);

	kfree(dev->padding_pkt);



	free_netdev(net);

}
@@ -1679,9 +1685,16 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod) 
	/* initialize max rx_qlen and tx_qlen */

	usbnet_update_max_qlen(dev);



	if (dev->can_dma_sg && !(info->flags & FLAG_SEND_ZLP) &&

		!(info->flags & FLAG_MULTI_PACKET)) {

		dev->padding_pkt = kzalloc(1, GFP_KERNEL);

		if (!dev->padding_pkt)

			goto out4;

	}



	status = register_netdev (net);

	if (status)

		goto out4;

		goto out5;

	netif_info(dev, probe, dev->net,

		   "register '%s' at usb-%s-%s, %s, %pM\n",

		   udev->dev.driver->name,
@@ -1699,6 +1712,8 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod) 


	return 0;



out5:

	kfree(dev->padding_pkt);

out4:

	usb_free_urb(dev->interrupt);

out3:

include/linux/usb/usbnet.h

+1 −0
Original line number Diff line number Diff line
@@ -42,6 +42,7 @@ struct usbnet { 
	struct usb_host_endpoint *status;

	unsigned		maxpacket;

	struct timer_list	delay;

	const char		*padding_pkt;



	/* protocol/interface state */

	struct net_device	*net;

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