mac80211: move TX info into skb->cb

This patch converts mac80211 and all drivers to have transmit
information and status in skb->cb rather than allocating extra
memory for it and copying all the data around. To make it fit,
a union is used where only data that is necessary for all steps
is kept outside of the union.

A number of fixes were done by Ivo, as well as the rt2x00 part
of this patch.

Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2500usb.c b/drivers/net/wireless/rt2x00/rt2500usb.c
index 4122c5e..cca1504 100644
--- a/drivers/net/wireless/rt2x00/rt2500usb.c
+++ b/drivers/net/wireless/rt2x00/rt2500usb.c
@@ -1666,13 +1666,12 @@
 /*
  * IEEE80211 stack callback functions.
  */
-static int rt2500usb_beacon_update(struct ieee80211_hw *hw,
-				   struct sk_buff *skb,
-				   struct ieee80211_tx_control *control)
+static int rt2500usb_beacon_update(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;
 	struct usb_device *usb_dev = rt2x00dev_usb_dev(rt2x00dev);
-	struct rt2x00_intf *intf = vif_to_intf(control->vif);
+	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
+	struct rt2x00_intf *intf = vif_to_intf(tx_info->control.vif);
 	struct queue_entry_priv_usb_bcn *bcn_priv;
 	struct skb_frame_desc *skbdesc;
 	struct txentry_desc txdesc;
@@ -1691,7 +1690,7 @@
 	 * for our information.
 	 */
 	intf->beacon->skb = skb;
-	rt2x00queue_create_tx_descriptor(intf->beacon, &txdesc, control);
+	rt2x00queue_create_tx_descriptor(intf->beacon, &txdesc);
 
 	/*
 	 * Add the descriptor in front of the skb.