mac80211: Fix ieee80211_sta_conn_mon_timer with hw connection monitoring

When IEEE80211_HW_CONNECTION_MONITOR is configured by the driver, starting
of ieee80211_sta_conn_mon_timer should be prevented, as it is then not needed.

This is currently partially the case. As it seems, when a probe-response is
received from the AP the timer is still restarted, thus restarting the host
based connection keep-alive mechanism. These probe-responses happen at least
when scanning while associated.

Fix this by preventing starting of the ieee80211_sta_conn_mon_timer in the
ieee80211_rx_mgmt_probe_resp function.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

net/mac80211/mlme.c

@@ -1330,12 +1330,17 @@ static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
 		mutex_lock(&sdata->local->iflist_mtx);
 		ieee80211_recalc_ps(sdata->local, -1);
 		mutex_unlock(&sdata->local->iflist_mtx);
+
+		if (sdata->local->hw.flags & IEEE80211_HW_CONNECTION_MONITOR)
+			return;
+
 		/*
 		 * We've received a probe response, but are not sure whether
 		 * we have or will be receiving any beacons or data, so let's
 		 * schedule the timers again, just in case.
 		 */
 		mod_beacon_timer(sdata);
+
 		mod_timer(&ifmgd->conn_mon_timer,
 			  round_jiffies_up(jiffies +
 					   IEEE80211_CONNECTION_IDLE_TIME));