[Adding James]

Hi Jiapeng,

On Fri, May 06, 2022 at 05:17:18PM +0800, Jiapeng Chong wrote:

Clean the following coccicheck warning:

./tools/perf/util/cs-etm.c:418:34-35: WARNING opportunity for swap().

Reported-by: Abaci Robot abaci@linux.alibaba.com Signed-off-by: Jiapeng Chong jiapeng.chong@linux.alibaba.com

---

tools/perf/util/cs-etm.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 8b95fb3c4d7b..0cb555cc766f 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -406,18 +406,13 @@ struct cs_etm_packet_queue static void cs_etm__packet_swap(struct cs_etm_auxtrace *etm, struct cs_etm_traceid_queue *tidq) {

• struct cs_etm_packet *tmp;
• if (etm->synth_opts.branches || etm->synth_opts.last_branch ||

•    etm->synth_opts.instructions) {
  

•    etm->synth_opts.instructions)
  

  /*
  • Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
  • the next incoming packet.
  */

• tmp = tidq->packet;
  

• tidq->packet = tidq->prev_packet;
  

• tidq->prev_packet = tmp;
  

Those 3 lines have burned a lot of eyes... As far as I can remember the idea is simply to make sure that after that point, ->prev_packet is now set to ->packet in preparation for the next iteration. There is no point in setting ->packet to ->prev_packet. As such the following would work just fine:

tidq->prev_packet = tidq->packet;

... but I will let James and Leo have a final say on that.

• }

• swap(tidq->packet, tidq->prev_packet);
  

If we absolutely need to keep swapping the packets please add the header file where swap() is found.

Thanks, Mathieu

} static void cs_etm__packet_dump(const char *pkt_string) -- 2.20.1.7.g153144c