USBNET: fix handling padding packet
Commit 638c5115a7949(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: David Laight <David.Laight@aculab.com>
Acked-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 7b331e6..bf94e10 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1241,7 +1241,9 @@
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 @@
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 @@
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 @@
usb_kill_urb(dev->interrupt);
usb_free_urb(dev->interrupt);
+ kfree(dev->padding_pkt);
free_netdev(net);
}
@@ -1679,9 +1685,16 @@
/* 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 @@
return 0;
+out5:
+ kfree(dev->padding_pkt);
out4:
usb_free_urb(dev->interrupt);
out3: