From 60e453a940ac678565b6641d65f8c18541bb9f28 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Mon, 23 Sep 2013 20:59:35 +0800 Subject: [PATCH] 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 Acked-by: Oliver Neukum Signed-off-by: Ming Lei Signed-off-by: David S. Miller --- drivers/net/usb/usbnet.c | 27 +++++++++++++++++++++------ include/linux/usb/usbnet.h | 1 + 2 files changed, 22 insertions(+), 6 deletions(-) diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c index 7b331e613e02..bf94e10a37c8 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -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: diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h index 9cb2fe8ca944..e303eef94dd5 100644 --- a/include/linux/usb/usbnet.h +++ b/include/linux/usb/usbnet.h @@ -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; -- 2.20.1