[PATCH 2/2] net: asix: handle packets crossing URB boundaries

[Lucas Stach <dev-8ppwABl0HbeELgA04lAiVw@public.gmane.org>]

ASIX AX88772B started to pack data even more tightly. Packets and the ASIX packet
header may now cross URB boundaries. To handle this we have to introduce
some state between individual calls to asix_rx_fixup().

Signed-off-by: Lucas Stach <dev-8ppwABl0HbeELgA04lAiVw@public.gmane.org>
---
I've running this patch for some weeks already now and it gets rid of all
the commonly seen rx failures with AX88772B.
---
 drivers/net/usb/asix.h         | 10 ++++++
 drivers/net/usb/asix_common.c  | 81 +++++++++++++++++++++++++++++-------------
 drivers/net/usb/asix_devices.c |  8 +++++
 3 Dateien geändert, 75 Zeilen hinzugefügt(+), 24 Zeilen entfernt(-)

diff --git a/drivers/net/usb/asix.h b/drivers/net/usb/asix.h
index e889631..3b4f7a8 100644
--- a/drivers/net/usb/asix.h
+++ b/drivers/net/usb/asix.h
@@ -167,6 +167,16 @@ struct asix_data {
 	u8 res;
 };
 
+struct asix_rx_fixup_info {
+	struct sk_buff *ax_skb;
+	u32 header;
+	u16 size;
+	bool split_head;
+};
+struct asix_private {
+	struct asix_rx_fixup_info rx_fixup_info;
+};
+
 int asix_read_cmd(struct usbnet *dev, u8 cmd, u16 value, u16 index,
 		  u16 size, void *data);
 
diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c
index 50d1673..17f9801 100644
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -53,44 +53,77 @@ void asix_write_cmd_async(struct usbnet *dev, u8 cmd, u16 value, u16 index,
 
 int asix_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
 {
+	struct asix_private *dp = dev->driver_priv;
+	struct asix_rx_fixup_info *rx = &dp->rx_fixup_info;
 	int offset = 0;
 
-	while (offset + sizeof(u32) < skb->len) {
-		struct sk_buff *ax_skb;
-		u16 size;
-		u32 header = get_unaligned_le32(skb->data + offset);
-
-		offset += sizeof(u32);
-
-		/* get the packet length */
-		size = (u16) (header & 0x7ff);
-		if (size != ((~header >> 16) & 0x07ff)) {
-			netdev_err(dev->net, "asix_rx_fixup() Bad Header Length\n");
-			return 0;
+	while (offset + sizeof(u16) <= skb->len) {
+		u16 remaining = 0;
+		unsigned char *data;
+
+		if (!rx->size) {
+			if ((skb->len - offset == sizeof(u16)) ||
+			    rx->split_head) {
+				if(!rx->split_head) {
+					rx->header = get_unaligned_le16(
+							skb->data + offset);
+					rx->split_head = true;
+					offset += sizeof(u16);
+					break;
+				} else {
+					rx->header |= (get_unaligned_le16(
+							skb->data + offset)
+							<< 16);
+					rx->split_head = false;
+					offset += sizeof(u16);
+				}
+			} else {
+				rx->header = get_unaligned_le32(skb->data +
+								offset);
+				offset += sizeof(u32);
+			}
+
+			/* get the packet length */
+			rx->size = (u16) (rx->header & 0x7ff);
+			if (rx->size != ((~rx->header >> 16) & 0x7ff)) {
+				netdev_err(dev->net, "asix_rx_fixup() Bad Header Length 0x%x, offset %d\n",
+					   rx->header, offset);
+				rx->size = 0;
+				return 0;
+			}
+			rx->ax_skb = netdev_alloc_skb_ip_align(dev->net,
+							       rx->size);
+			if (!rx->ax_skb)
+				return 0;
 		}
 
-		if ((size > dev->net->mtu + ETH_HLEN + VLAN_HLEN) ||
-		    (size + offset > skb->len)) {
+		if (rx->size > dev->net->mtu + ETH_HLEN + VLAN_HLEN) {
 			netdev_err(dev->net, "asix_rx_fixup() Bad RX Length %d\n",
-				   size);
+				   rx->size);
+			kfree_skb(rx->ax_skb);
 			return 0;
 		}
-		ax_skb = netdev_alloc_skb_ip_align(dev->net, size);
-		if (!ax_skb)
-			return 0;
 
-		skb_put(ax_skb, size);
-		memcpy(ax_skb->data, skb->data + offset, size);
-		usbnet_skb_return(dev, ax_skb);
+		if (rx->size > skb->len - offset) {
+			remaining = rx->size - (skb->len - offset);
+			rx->size = skb->len - offset;
+		}
+
+		data = skb_put(rx->ax_skb, rx->size);
+		memcpy(data, skb->data + offset, rx->size);
+		if (!remaining)
+			usbnet_skb_return(dev, rx->ax_skb);
 
-		offset += (size + 1) & 0xfffe;
+		offset += (rx->size + 1) & 0xfffe;
+		rx->size = remaining;
 	}
 
 	if (skb->len != offset) {
-		netdev_err(dev->net, "asix_rx_fixup() Bad SKB Length %d\n",
-			   skb->len);
+		netdev_err(dev->net, "asix_rx_fixup() Bad SKB Length %d, %d\n",
+			   skb->len, offset);
 		return 0;
 	}
+
 	return 1;
 }
 
diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index 06f7f7cb..2e1f3ec 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -495,6 +495,10 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
 		dev->rx_urb_size = 2048;
 	}
 
+	dev->driver_priv = kzalloc(sizeof(struct asix_private), GFP_KERNEL);
+	if (!dev->driver_priv)
+		return -ENOMEM;
+
 	return 0;
 }
 
@@ -829,6 +833,10 @@ static int ax88178_bind(struct usbnet *dev, struct usb_interface *intf)
 		dev->rx_urb_size = 2048;
 	}
 
+	dev->driver_priv = kzalloc(sizeof(struct asix_private), GFP_KERNEL);
+	if (!dev->driver_priv)
+			return -ENOMEM;
+
 	return 0;
 }
 
-- 
1.7.11.7

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html