Subject: [PATCH v2 2/2] net: asix: handle packets crossing URB boundaries

From: Lucas Stach <[email-masked]>
Date: Tue, 18 Dec 2012 16:21:23 +0100

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 <[email-masked]>
---
I've running this patch for some weeks already now and it gets rid of all
the commonly seen rx failures with AX88772B.

v2: don't forget to free driver_private
---
 drivers/net/usb/asix.h         | 11 ++++++
 drivers/net/usb/asix_common.c  | 81 +++++++++++++++++++++++++++++-------------
 drivers/net/usb/asix_devices.c | 17 +++++++++
 3 Dateien geändert, 85 Zeilen hinzugefügt(+), 24 Zeilen entfernt(-)

diff --git a/drivers/net/usb/asix.h b/drivers/net/usb/asix.h
index 7afe8ac..4dfdbf6 100644
--- a/drivers/net/usb/asix.h
+++ b/drivers/net/usb/asix.h
@@ -167,6 +167,17 @@ 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;
+};
+
 /* ASIX specific flags */
 #define FLAG_EEPROM_MAC		(1UL << 0)  /* init device MAC from eeprom */
 
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 0ecc3bc..c651243 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -495,9 +495,19 @@ 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;
 }
 
+void ax88772_unbind(struct usbnet *dev, struct usb_interface *intf)
+{
+	if (dev->driver_priv)
+		kfree(dev->driver_priv);
+}
+
 static const struct ethtool_ops ax88178_ethtool_ops = {
 	.get_drvinfo		= asix_get_drvinfo,
 	.get_link		= asix_get_link,
@@ -829,6 +839,10 @@ 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;
 }
 
@@ -875,6 +889,7 @@ static const struct driver_info hawking_uf200_info = {
 static const struct driver_info ax88772_info = {
 	.description = "ASIX AX88772 USB 2.0 Ethernet",
 	.bind = ax88772_bind,
+	.unbind = ax88772_unbind,
 	.status = asix_status,
 	.link_reset = ax88772_link_reset,
 	.reset = ax88772_reset,
@@ -886,6 +901,7 @@ static const struct driver_info ax88772_info = {
 static const struct driver_info ax88772b_info = {
 	.description = "ASIX AX88772B USB 2.0 Ethernet",
 	.bind = ax88772_bind,
+	.unbind = ax88772_unbind,
 	.status = asix_status,
 	.link_reset = ax88772_link_reset,
 	.reset = ax88772_reset,
@@ -899,6 +915,7 @@ static const struct driver_info ax88772b_info = {
 static const struct driver_info ax88178_info = {
 	.description = "ASIX AX88178 USB 2.0 Ethernet",
 	.bind = ax88178_bind,
+	.unbind = ax88772_unbind,
 	.status = asix_status,
 	.link_reset = ax88178_link_reset,
 	.reset = ax88178_reset,
-- 
1.7.11.7

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