[PATCH 1/2] drivers/perf: hisi_pcie: Check the type first in pmu::event_init()

[Yicong Yang]

From: Yicong Yang <yangyicong@xxxxxxxxxxxxx>

Check whether the event type matches the PMU type firstly in
pmu::event_init() before touching the event. Otherwise we'll
change the events of others and lead to incorrect results.
Since in perf_init_event() we may call every pmu's event_init()
in a certain case, we should not modify the event if it's not
ours.

Fixes: 8404b0fbc7fb ("drivers/perf: hisi: Add driver for HiSilicon PCIe PMU")
Signed-off-by: Yicong Yang <yangyicong@xxxxxxxxxxxxx>
---
 drivers/perf/hisilicon/hisi_pcie_pmu.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/perf/hisilicon/hisi_pcie_pmu.c b/drivers/perf/hisilicon/hisi_pcie_pmu.c
index 5a00adb2de8c..051efffc44c8 100644
--- a/drivers/perf/hisilicon/hisi_pcie_pmu.c
+++ b/drivers/perf/hisilicon/hisi_pcie_pmu.c
@@ -353,6 +353,10 @@ static int hisi_pcie_pmu_event_init(struct perf_event *event)
 	struct hisi_pcie_pmu *pcie_pmu = to_pcie_pmu(event->pmu);
 	struct hw_perf_event *hwc = &event->hw;
 
+	/* Check the type first before going on, otherwise it's not our event */
+	if (event->attr.type != event->pmu->type)
+		return -ENOENT;
+
 	event->cpu = pcie_pmu->on_cpu;
 
 	if (EXT_COUNTER_IS_USED(hisi_pcie_get_event(event)))
@@ -360,9 +364,6 @@ static int hisi_pcie_pmu_event_init(struct perf_event *event)
 	else
 		hwc->event_base = HISI_PCIE_CNT;
 
-	if (event->attr.type != event->pmu->type)
-		return -ENOENT;
-
 	/* Sampling is not supported. */
 	if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK)
 		return -EOPNOTSUPP;
-- 
2.24.0