iwlwifi: mvm: Disconnect on large beacon loss

Some buggy APs stop sending beacons, but continue to ack our null data
packets or even run some traffic. It's better not to stick connected to
such an AP forever, so disconnect after some larger beacon loss
threshold is crossed.
Signed-off-by: Andrei Otcheretianski <andrei.otcheretianski@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c

@@ -1415,8 +1415,9 @@ void iwl_mvm_rx_missed_beacons_notif(struct iwl_mvm *mvm,
 	 * TODO: the threshold should be adjusted based on latency conditions,
 	 * and/or in case of a CS flow on one of the other AP vifs.
 	 */
-	if (le32_to_cpu(mb->consec_missed_beacons_since_last_rx) >
-	     IWL_MVM_MISSED_BEACONS_THRESHOLD)
+	if (rx_missed_bcon > IWL_MVM_MISSED_BEACONS_THRESHOLD_LONG)
+		iwl_mvm_connection_loss(mvm, vif, "missed beacons");
+	else if (rx_missed_bcon_since_rx > IWL_MVM_MISSED_BEACONS_THRESHOLD)
 		ieee80211_beacon_loss(vif);
 
 	trigger = iwl_fw_dbg_trigger_on(&mvm->fwrt, ieee80211_vif_to_wdev(vif),

drivers/net/wireless/intel/iwlwifi/mvm/mvm.h

@@ -94,6 +94,8 @@
 /* RSSI offset for WkP */
 #define IWL_RSSI_OFFSET 50
 #define IWL_MVM_MISSED_BEACONS_THRESHOLD 8
+#define IWL_MVM_MISSED_BEACONS_THRESHOLD_LONG 16
+
 /* A TimeUnit is 1024 microsecond */
 #define MSEC_TO_TU(_msec)	(_msec*1000/1024)