[tip:perf/core] ftrace/perf: Check sample types only for sampling events

[tip-bot for Jiri Olsa]

Commit-ID:  0a74c5b3d20d2a8693848b6ae4f1a97624f5b781
Gitweb:     http://git.kernel.org/tip/0a74c5b3d20d2a8693848b6ae4f1a97624f5b781
Author:     Jiri Olsa <jolsa@xxxxxxxxxx>
AuthorDate: Wed, 16 Mar 2016 15:34:29 +0100
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 31 Mar 2016 10:30:45 +0200

ftrace/perf: Check sample types only for sampling events

Currently we check sample type for ftrace:function events
even if it's not created as a sampling event. That prevents
creating ftrace_function event in counting mode.

Make sure we check sample types only for sampling events.

Before:
  $ sudo perf stat -e ftrace:function ls
  ...

   Performance counter stats for 'ls':

     <not supported>      ftrace:function

         0.001983662 seconds time elapsed

After:
  $ sudo perf stat -e ftrace:function ls
  ...

   Performance counter stats for 'ls':

              44,498      ftrace:function

         0.037534722 seconds time elapsed

Suggested-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1458138873-1553-2-git-send-email-jolsa@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 kernel/trace/trace_event_perf.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 00df25f..e11108f 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -47,6 +47,9 @@ static int perf_trace_event_perm(struct trace_event_call *tp_event,
 		if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
 			return -EPERM;
 
+		if (!is_sampling_event(p_event))
+			return 0;
+
 		/*
 		 * We don't allow user space callchains for  function trace
 		 * event, due to issues with page faults while tracing page