perf arm-spe: Refactor arm_spe_get_events()

In function arm_spe_get_events(), the event packet's 'index' is assigned
as payload length, but the flow is not directive: it firstly gets the
packet length from the return value of arm_spe_get_payload(), the value
includes header length (1) and payload length:

  int ret = arm_spe_get_payload(buf, len, packet);

and then reduces header length from packet length, so finally get the
payload length:

  packet->index = ret - 1;

To simplify the code, this patch directly assigns payload length to
event packet's index; and at the end it calls arm_spe_get_payload() to
return the payload value.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20201111071149.815-5-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
index a8eb7be..57904da 100644 (file)
--- a/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
+++ b/tools/perf/util/arm-spe-decoder/arm-spe-pkt-decoder.c
@@ -136,8 +136,6 @@ static int arm_spe_get_timestamp(const unsigned char *buf, size_t len,
 static int arm_spe_get_events(const unsigned char *buf, size_t len,
                              struct arm_spe_pkt *packet)
 {
-       int ret = arm_spe_get_payload(buf, len, packet);
-
        packet->type = ARM_SPE_EVENTS;
 
        /* we use index to identify Events with a less number of
@@ -145,9 +143,9 @@ static int arm_spe_get_events(const unsigned char *buf, size_t len,
         * LLC-REFILL, and REMOTE-ACCESS events are identified if
         * index > 1.
         */
-       packet->index = ret - 1;
+       packet->index = arm_spe_payload_len(buf[0]);
 
-       return ret;
+       return arm_spe_get_payload(buf, len, packet);
 }
 
 static int arm_spe_get_data_source(const unsigned char *buf, size_t len,