How about limiting refresh ioctl to sampling events ?

[Franck Bui-Huu <vagabon.xyz@gmail.com>]

Hello Peter,

I'm looking at the perf event stuff and wondering if
perf_event_refresh() should be limited to sampling events.

Does the following make sense ?

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 3b105e0..1a90a6c 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -1072,7 +1072,7 @@ static int perf_event_refresh(struct perf_event *event, int refresh)
 	/*
 	 * not supported on inherited events
 	 */
-	if (event->attr.inherit)
+	if (event->attr.inherit || !event->attr.sample_period)
 		return -EINVAL;
 
 	atomic_add(refresh, &event->event_limit);

Thanks
-- 
		Franck