rt2x00: Request usb_maxpacket() once

The usb max packet size won't change during the
device's presence. We should store it in a
variable inside rt2x00dev and use that.
This should also fix a division error when the
device is being hot-unplugged while a frame is
being send out.
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2500usb.c

@@ -1032,7 +1032,7 @@ static void rt2500usb_write_tx_desc(struct rt2x00_dev *rt2x00dev,
 }
 
 static int rt2500usb_get_tx_data_len(struct rt2x00_dev *rt2x00dev,
-				     int maxpacket, struct sk_buff *skb)
+				     struct sk_buff *skb)
 {
 	int length;
 
@@ -1041,7 +1041,7 @@ static int rt2500usb_get_tx_data_len(struct rt2x00_dev *rt2x00dev,
 	 * but it must _not_ be a multiple of the USB packet size.
 	 */
 	length = roundup(skb->len, 2);
-	length += (2 * !(length % maxpacket));
+	length += (2 * !(length % rt2x00dev->usb_maxpacket));
 
 	return length;
 }
@@ -1643,7 +1643,6 @@ static int rt2500usb_beacon_update(struct ieee80211_hw *hw,
 	struct data_entry *beacon;
 	struct data_entry *guardian;
 	int pipe = usb_sndbulkpipe(usb_dev, 1);
-	int max_packet = usb_maxpacket(usb_dev, pipe, 1);
 	int length;
 
 	/*
@@ -1672,7 +1671,7 @@ static int rt2500usb_beacon_update(struct ieee80211_hw *hw,
 							 ring->desc_size),
 				skb->len - ring->desc_size, control);
 
-	length = rt2500usb_get_tx_data_len(rt2x00dev, max_packet, skb);
+	length = rt2500usb_get_tx_data_len(rt2x00dev, skb);
 
 	usb_fill_bulk_urb(beacon->priv, usb_dev, pipe,
 			  skb->data, length, rt2500usb_beacondone, beacon);

drivers/net/wireless/rt2x00/rt2x00.h

@@ -418,7 +418,7 @@ struct rt2x00lib_ops {
 	int (*write_tx_data) (struct rt2x00_dev *rt2x00dev,
 			      struct data_ring *ring, struct sk_buff *skb,
 			      struct ieee80211_tx_control *control);
-	int (*get_tx_data_len) (struct rt2x00_dev *rt2x00dev, int maxpacket,
+	int (*get_tx_data_len) (struct rt2x00_dev *rt2x00dev,
 				struct sk_buff *skb);
 	void (*kick_tx_queue) (struct rt2x00_dev *rt2x00dev,
 			       unsigned int queue);
@@ -598,6 +598,11 @@ struct rt2x00_dev {
 	 */
 	u32 *rf;
 
+	/*
+	 * USB Max frame size (for rt2500usb & rt73usb).
+	 */
+	u16 usb_maxpacket;
+
 	/*
 	 * Current TX power value.
 	 */

drivers/net/wireless/rt2x00/rt2x00usb.c

@@ -159,7 +159,6 @@ int rt2x00usb_write_tx_data(struct rt2x00_dev *rt2x00dev,
 	    interface_to_usbdev(rt2x00dev_usb(rt2x00dev));
 	struct data_entry *entry = rt2x00_get_data_entry(ring);
 	int pipe = usb_sndbulkpipe(usb_dev, 1);
-	int max_packet = usb_maxpacket(usb_dev, pipe, 1);
 	u32 length;
 
 	if (rt2x00_ring_full(ring)) {
@@ -194,8 +193,7 @@ int rt2x00usb_write_tx_data(struct rt2x00_dev *rt2x00dev,
 	 * length of the data to usb_fill_bulk_urb. Pass the skb
 	 * to the driver to determine what the length should be.
 	 */
-	length = rt2x00dev->ops->lib->get_tx_data_len(rt2x00dev,
-						      max_packet, skb);
+	length = rt2x00dev->ops->lib->get_tx_data_len(rt2x00dev, skb);
 
 	/*
 	 * Initialize URB and send the frame to the device.
@@ -490,6 +488,11 @@ int rt2x00usb_probe(struct usb_interface *usb_intf,
 	rt2x00dev->ops = ops;
 	rt2x00dev->hw = hw;
 
+	rt2x00dev->usb_maxpacket =
+	    usb_maxpacket(usb_dev, usb_sndbulkpipe(usb_dev, 1), 1);
+	if (!rt2x00dev->usb_maxpacket)
+		rt2x00dev->usb_maxpacket = 1;
+
 	retval = rt2x00usb_alloc_reg(rt2x00dev);
 	if (retval)
 		goto exit_free_device;

drivers/net/wireless/rt2x00/rt73usb.c

@@ -1251,7 +1251,7 @@ static void rt73usb_write_tx_desc(struct rt2x00_dev *rt2x00dev,
 }
 
 static int rt73usb_get_tx_data_len(struct rt2x00_dev *rt2x00dev,
-				   int maxpacket, struct sk_buff *skb)
+				   struct sk_buff *skb)
 {
 	int length;
 
@@ -1260,7 +1260,7 @@ static int rt73usb_get_tx_data_len(struct rt2x00_dev *rt2x00dev,
 	 * but it must _not_ be a multiple of the USB packet size.
 	 */
 	length = roundup(skb->len, 4);
-	length += (4 * !(length % maxpacket));
+	length += (4 * !(length % rt2x00dev->usb_maxpacket));
 
 	return length;
 }