[PATCH -tip v3 4/9] selftests: ftrace: Check whether snapshot trigger is supported correctly

[Masami Hiramatsu]

If "snapshot" special file doesn't exist, that kernel does
not support snapshot and snapshot trigger too. In that case
snapshot trigger test results to unsupported instead of fail.

Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
 .../ftrace/test.d/trigger/trigger-snapshot.tc      |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tools/testing/selftests/ftrace/test.d/trigger/trigger-snapshot.tc b/tools/testing/selftests/ftrace/test.d/trigger/trigger-snapshot.tc
index f84b80d..ed94f0c 100644
--- a/tools/testing/selftests/ftrace/test.d/trigger/trigger-snapshot.tc
+++ b/tools/testing/selftests/ftrace/test.d/trigger/trigger-snapshot.tc
@@ -23,6 +23,11 @@ if [ ! -f events/sched/sched_process_fork/trigger ]; then
     exit_unsupported
 fi
 
+if [ ! -f snapshot ]; then
+    echo "snapshot is not supported"
+    exit_unsupported
+fi
+
 reset_tracer
 do_reset