drivers/perf: arm_pmu: remove pointless PMU disabling

We currently disable the PMU temporarily in armpmu_add(). We may have
required this historically, but the perf core always disables an event's
PMU when calling event::pmu::add(), so this is not necessary.

We don't do similarly in armpmu_del(), or elsewhere, so this is
unnecessary and inconsistent, and only serves to confuse the reader.

Remove the pointless disable, simplifying armpmu_add() in the process.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index a1dfe895cb1db410a2c17f491c2ab413c1fc0742..316c4dcc9856c603f50227c7c1c9a286ea3facd2 100644 (file)
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -235,20 +235,15 @@ armpmu_add(struct perf_event *event, int flags)
        struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events);
        struct hw_perf_event *hwc = &event->hw;
        int idx;
-       int err = 0;
 
        /* An event following a process won't be stopped earlier */
        if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus))
                return -ENOENT;
 
-       perf_pmu_disable(event->pmu);
-
        /* If we don't have a space for the counter then finish early. */
        idx = armpmu->get_event_idx(hw_events, event);
-       if (idx < 0) {
-               err = idx;
-               goto out;
-       }
+       if (idx < 0)
+               return idx;
 
        /*
         * If there is an event in the counter we are going to use then make
@@ -265,9 +260,7 @@ armpmu_add(struct perf_event *event, int flags)
        /* Propagate our changes to the userspace mapping. */
        perf_event_update_userpage(event);
 
-out:
-       perf_pmu_enable(event->pmu);
-       return err;
+       return 0;
 }
 
 static int