mac80211: Look out for some other AP when disassoc is received.

When a disassoc packet is received from the AP with a reason code of
'leaving the BSS', mac80211 should go into DISABLED state just as it
would do if the AP suddenly went away for some reason, as that is what
will happen shortly after the AP leaves anyway.
Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/mlme.c

@@ -802,6 +802,10 @@ static void ieee80211_authenticate(struct ieee80211_sub_if_data *sdata,
 	mod_timer(&ifsta->timer, jiffies + IEEE80211_AUTH_TIMEOUT);
 }
 
+/*
+ * The disassoc 'reason' argument can be either our own reason
+ * if self disconnected or a reason code from the AP.
+ */
 static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata,
 				   struct ieee80211_if_sta *ifsta, bool deauth,
 				   bool self_disconnected, u16 reason)
@@ -848,7 +852,7 @@ static void ieee80211_set_disassoc(struct ieee80211_sub_if_data *sdata,
 
 	ieee80211_sta_send_apinfo(sdata, ifsta);
 
-	if (self_disconnected)
+	if (self_disconnected || reason == WLAN_REASON_DISASSOC_STA_HAS_LEFT)
 		ifsta->state = IEEE80211_STA_MLME_DISABLED;
 
 	sta_info_unlink(&sta);
@@ -1163,7 +1167,7 @@ static void ieee80211_rx_mgmt_disassoc(struct ieee80211_sub_if_data *sdata,
 				      IEEE80211_RETRY_AUTH_INTERVAL);
 	}
 
-	ieee80211_set_disassoc(sdata, ifsta, false, false, 0);
+	ieee80211_set_disassoc(sdata, ifsta, false, false, reason_code);
 }