drivers/perf: hisi_pcie: Check the type first in pmu::event_init()

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: 8404b0f ("drivers/perf: hisi: Add driver for HiSilicon PCIe PMU")
Signed-off-by: Yicong Yang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

Author: Yicong Yang

drivers/perf/hisilicon/hisi_pcie_pmu.c

@@ -353,16 +353,17 @@ 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)))
 		hwc->event_base = HISI_PCIE_EXT_CNT;
 	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;