[BUGFIX PATCH v3 1/4] selftests/ftrace: Fix to check the existence of set_ftrace_filter

[Masami Hiramatsu <mhiramat@kernel.org>]

If we run ftracetest on the kernel with CONFIG_DYNAMIC_FTRACE=n,
there is no set_ftrace_filter and all test cases are failed,
because reset_ftrace_filter returns an error.
Let's check whether set_ftrace_filter exists and remove redundant
set_ftrace_filter from initialize_ftrace().

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 tools/testing/selftests/ftrace/test.d/functions |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions
index 86986c4bba54..19d288cdf336 100644
--- a/tools/testing/selftests/ftrace/test.d/functions
+++ b/tools/testing/selftests/ftrace/test.d/functions
@@ -46,6 +46,9 @@ reset_events_filter() { # reset all current setting filters
 }
 
 reset_ftrace_filter() { # reset all triggers in set_ftrace_filter
+    if [ ! -f set_ftrace_filter ]; then
+      return 0
+    fi
     echo > set_ftrace_filter
     grep -v '^#' set_ftrace_filter | while read t; do
 	tr=`echo $t | cut -d: -f2`
@@ -93,7 +96,6 @@ initialize_ftrace() { # Reset ftrace to initial-state
     disable_events
     [ -f set_event_pid ] && echo > set_event_pid
     [ -f set_ftrace_pid ] && echo > set_ftrace_pid
-    [ -f set_ftrace_filter ] && echo | tee set_ftrace_*
     [ -f set_graph_function ] && echo | tee set_graph_*
     [ -f stack_trace_filter ] && echo > stack_trace_filter
     [ -f kprobe_events ] && echo > kprobe_events