perf cs-etm: Don't check cs_etm_queue::prev_packet validity

Since cs_etm_queue::prev_packet is allocated for all cases, it will
never be NULL pointer; now validity checking prev_packet is pointless,
remove all of them.

Signed-off-by: Leo Yan <[email protected]>
Tested-by: Robert Walker <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Suzuki K Poulouse <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/perf/util/cs-etm.c

@@ -981,7 +981,6 @@ static int cs_etm__sample(struct cs_etm_queue *etmq)
 	 * PREV_PACKET is a branch.
 	 */
 	if (etm->synth_opts.last_branch &&
-	    etmq->prev_packet &&
 	    etmq->prev_packet->sample_type == CS_ETM_RANGE &&
 	    etmq->prev_packet->last_instr_taken_branch)
 		cs_etm__update_last_branch_rb(etmq);
@@ -1014,7 +1013,7 @@ static int cs_etm__sample(struct cs_etm_queue *etmq)
 		etmq->period_instructions = instrs_over;
 	}
 
-	if (etm->sample_branches && etmq->prev_packet) {
+	if (etm->sample_branches) {
 		bool generate_sample = false;
 
 		/* Generate sample for tracing on packet */
@@ -1071,9 +1070,6 @@ static int cs_etm__flush(struct cs_etm_queue *etmq)
 	struct cs_etm_auxtrace *etm = etmq->etm;
 	struct cs_etm_packet *tmp;
 
-	if (!etmq->prev_packet)
-		return 0;
-
 	/* Handle start tracing packet */
 	if (etmq->prev_packet->sample_type == CS_ETM_EMPTY)
 		goto swap_packet;