ARM: perf: remove unnecessary checks for idx < 0

We currently check for hwx->idx < 0 in armpmu_read and armpmu_del
unnecessarily. The only case where hwc->idx < 0 is when armpmu_add
fails, in which case the event's state is set to
PERF_EVENT_STATE_INACTIVE.

The perf core will not attempt to read from an event in
PERF_EVENT_STATE_INACTIVE, and so the check in armpmu_read is
unnecessary. Similarly, if perf core cannot add an event it will not
attempt to delete it, so the WARN_ON in armpmu_del is unnecessary.

This patch removes these two redundant checks.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm/kernel/perf_event.c b/arch/arm/kernel/perf_event.c
index f9e8657dd24122cf67362e4def103d41cfd25329..6df1969811c839c3e8ca5b0d1b268b9ad3f65902 100644 (file)
--- a/arch/arm/kernel/perf_event.c
+++ b/arch/arm/kernel/perf_event.c
@@ -149,12 +149,6 @@ again:
 static void
 armpmu_read(struct perf_event *event)
 {
-       struct hw_perf_event *hwc = &event->hw;
-
-       /* Don't read disabled counters! */
-       if (hwc->idx < 0)
-               return;
-
        armpmu_event_update(event);
 }
 
@@ -207,8 +201,6 @@ armpmu_del(struct perf_event *event, int flags)
        struct hw_perf_event *hwc = &event->hw;
        int idx = hwc->idx;
 
-       WARN_ON(idx < 0);
-
        armpmu_stop(event, PERF_EF_UPDATE);
        hw_events->events[idx] = NULL;
        clear_bit(idx, hw_events->used_mask);