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/iwlwifi/iwl-3945-rs.c b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
index f3ca02f..10c64bd 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-3945-rs.c
@@ -445,8 +445,7 @@
  */
 static void rs_tx_status(void *priv_rate,
 			 struct net_device *dev,
-			 struct sk_buff *skb,
-			 struct ieee80211_tx_status *tx_resp)
+			 struct sk_buff *skb)
 {
 	u8 retries, current_count;
 	int scale_rate_index, first_index, last_index;
@@ -457,14 +456,15 @@
 	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
 	struct iwl3945_rs_sta *rs_sta;
 	struct ieee80211_supported_band *sband;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 
 	IWL_DEBUG_RATE("enter\n");
 
 	sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 
 
-	retries = tx_resp->retry_count;
-	first_index = sband->bitrates[tx_resp->control.tx_rate_idx].hw_value;
+	retries = info->status.retry_count;
+	first_index = sband->bitrates[info->tx_rate_idx].hw_value;
 	if ((first_index < 0) || (first_index >= IWL_RATE_COUNT)) {
 		IWL_DEBUG_RATE("leave: Rate out of bounds: %d\n", first_index);
 		return;
@@ -525,11 +525,11 @@
 	/* Update the last index window with success/failure based on ACK */
 	IWL_DEBUG_RATE("Update rate %d with %s.\n",
 		       last_index,
-		       (tx_resp->flags & IEEE80211_TX_STATUS_ACK) ?
+		       (info->flags & IEEE80211_TX_STAT_ACK) ?
 		       "success" : "failure");
 	iwl3945_collect_tx_data(rs_sta,
 			    &rs_sta->win[last_index],
-			    tx_resp->flags & IEEE80211_TX_STATUS_ACK, 1);
+			    info->flags & IEEE80211_TX_STAT_ACK, 1);
 
 	/* We updated the rate scale window -- if its been more than
 	 * flush_time since the last run, schedule the flush