[PATCH 10/19] perf/arm-ni: Improve event validation

[Robin Murphy]

Although it is entirely benign for arm_ni_val_count_event() to count
any old hardware leader/sibling as an NI event (perf core will still
ultimately reject the cross-PMU group), it would still be nicer if it
didn't. Stop trying to special-case software events and simply skip any
event which doesn't belong to our PMU. Similarly drop the early return
paths since they can almost never actually return early.

Signed-off-by: Robin Murphy <robin.mur...@arm.com>
---
 drivers/perf/arm-ni.c | 29 +++++++++++++----------------
 1 file changed, 13 insertions(+), 16 deletions(-)

diff --git a/drivers/perf/arm-ni.c b/drivers/perf/arm-ni.c
index 1615a0564031..d6b683a0264e 100644
--- a/drivers/perf/arm-ni.c
+++ b/drivers/perf/arm-ni.c
@@ -271,40 +271,37 @@ static void arm_ni_pmu_disable(struct pmu *pmu)
 }
 
 struct arm_ni_val {
+       const struct pmu *pmu;
        unsigned int evcnt;
        unsigned int ccnt;
 };
 
-static bool arm_ni_val_count_event(struct perf_event *evt, struct arm_ni_val 
*val)
+static void arm_ni_val_count_event(struct perf_event *evt, struct arm_ni_val 
*val)
 {
-       if (is_software_event(evt))
-               return true;
-
-       if (NI_EVENT_TYPE(evt) == NI_PMU) {
-               val->ccnt++;
-               return val->ccnt <= 1;
+       if (evt->pmu == val->pmu) {
+               if (NI_EVENT_TYPE(evt) == NI_PMU)
+                       val->ccnt++;
+               else
+                       val->evcnt++;
        }
-
-       val->evcnt++;
-       return val->evcnt <= NI_NUM_COUNTERS;
 }
 
 static int arm_ni_validate_group(struct perf_event *event)
 {
        struct perf_event *sibling, *leader = event->group_leader;
-       struct arm_ni_val val = { 0 };
+       struct arm_ni_val val = { .pmu = event->pmu };
 
        if (leader == event)
                return 0;
 
        arm_ni_val_count_event(event, &val);
-       if (!arm_ni_val_count_event(leader, &val))
+       arm_ni_val_count_event(leader, &val);
+       for_each_sibling_event(sibling, leader)
+               arm_ni_val_count_event(sibling, &val);
+
+       if (val.evcnt > NI_NUM_COUNTERS || val.ccnt > 1)
                return -EINVAL;
 
-       for_each_sibling_event(sibling, leader) {
-               if (!arm_ni_val_count_event(sibling, &val))
-                       return -EINVAL;
-       }
        return 0;
 }
 
-- 
2.39.2.101.g768bb238c484.dirty