mac80211: make ieee80211_find_sta per virtual interface

Since we have a TODO item to make all station
management dependent on virtual interfaces, I
figured I'd start with pushing such a change
to drivers before more drivers start using the
ieee80211_find_sta() API with a hw pointer and
cause us grief later on.

For now continue exporting the old API in form
of ieee80211_find_sta_by_hw(), but discourage
its use strongly.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index e12293e..7f035d7 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2106,16 +2106,37 @@
 /**
  * ieee80211_find_sta - find a station
  *
- * @hw: pointer as obtained from ieee80211_alloc_hw()
+ * @vif: virtual interface to look for station on
  * @addr: station's address
  *
  * This function must be called under RCU lock and the
  * resulting pointer is only valid under RCU lock as well.
  */
-struct ieee80211_sta *ieee80211_find_sta(struct ieee80211_hw *hw,
+struct ieee80211_sta *ieee80211_find_sta(struct ieee80211_vif *vif,
 					 const u8 *addr);
 
 /**
+ * ieee80211_find_sta_by_hw - find a station on hardware
+ *
+ * @hw: pointer as obtained from ieee80211_alloc_hw()
+ * @addr: station's address
+ *
+ * This function must be called under RCU lock and the
+ * resulting pointer is only valid under RCU lock as well.
+ *
+ * NOTE: This function should not be used! When mac80211 is converted
+ *	 internally to properly keep track of stations on multiple
+ *	 virtual interfaces, it will not always know which station to
+ *	 return here since a single address might be used by multiple
+ *	 logical stations (e.g. consider a station connecting to another
+ *	 BSSID on the same AP hardware without disconnecting first).
+ *
+ * DO NOT USE THIS FUNCTION.
+ */
+struct ieee80211_sta *ieee80211_find_sta_by_hw(struct ieee80211_hw *hw,
+					       const u8 *addr);
+
+/**
  * ieee80211_beacon_loss - inform hardware does not receive beacons
  *
  * @vif: &struct ieee80211_vif pointer from &struct ieee80211_if_init_conf.