measurement: make sure state is reset on chan act.

At the moment only lchan_meas_reset is reset on channel activation.
All other states are not reset. This may lead to irretations in the
first measurement interval if there are still leftover messages from
a previous connection. Lets ensure everything is reset to zero by
zeroing out the whole .meas struct in struct lchan.

- Add a centralized function that does the reset
- Call that function from rsl_tx_chan_act_ack() in rsl.c

Change-Id: I880ae3030df6dcd60c32b7144c3430528429bdea
Related: OS#2975
Related: OS#2987

include/osmo-bts/measurement.h

@@ -10,4 +10,6 @@ int lchan_meas_check_compute(struct gsm_lchan *lchan, uint32_t fn);
 
 void lchan_meas_process_measurement(struct gsm_lchan *lchan, struct bts_ul_meas *ulm, uint32_t fn);
 
+void lchan_meas_reset(struct gsm_lchan *lchan);
+
 #endif

src/common/measurement.c

@@ -490,3 +490,11 @@ void lchan_meas_process_measurement(struct gsm_lchan *lchan, struct bts_ul_meas
 	 * measurment report at Meas period End */
 	lchan_meas_check_compute(lchan, fn);
 }
+
+/* Reset all measurement related struct members to their initial values. This
+ * function will be called every time an lchan is activated to ensure the
+ * measurement process starts with a defined state. */
+void lchan_meas_reset(struct gsm_lchan *lchan)
+{
+	memset(&lchan->meas, 0, sizeof(lchan->meas));
+}

src/common/rsl.c

@@ -750,7 +750,7 @@ static int rsl_tx_chan_act_ack(struct gsm_lchan *lchan)
 	msg->trx = lchan->ts->trx;
 
 	/* since activation was successful, do some lchan initialization */
-	lchan->meas.res_nr = 0;
+	lchan_meas_reset(lchan);
 
 	return abis_bts_rsl_sendmsg(msg);
 }