tracing: Reset ftrace_graph_filter_enabled if count is zero

The ftrace_graph_count can be decreased with a "!" pattern, so that
the enabled flag should be updated too.

Link: http://lkml.kernel.org/r/1365663698-2413-1-git-send-email-namhyung@kernel.org

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index c9f31491009f..9e3198782507 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3792,7 +3792,8 @@ out:
         if (fail)
                 return -EINVAL;
 
-        ftrace_graph_filter_enabled = 1;
+        ftrace_graph_filter_enabled = !!(*idx);
+
         return 0;
 }