tracing: Restore system filter behavior

Though not all events have field 'prev_pid', it was allowed to do this:

  # echo 'prev_pid == 100' > events/sched/filter

but commit 75b8e98263fdb0bfbdeba60d4db463259f1fe8a2 (tracing/filter: Swap
entire filter of events) broke it without any reason.

Link: http://lkml.kernel.org/r/4EAF46CF.8040408@cn.fujitsu.com

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index 96efa6794ea5..c3da42dd22ba 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -172,6 +172,7 @@ enum {
         TRACE_EVENT_FL_FILTERED_BIT,
         TRACE_EVENT_FL_RECORDED_CMD_BIT,
         TRACE_EVENT_FL_CAP_ANY_BIT,
+        TRACE_EVENT_FL_NO_SET_FILTER_BIT,
 };
 
 enum {
@@ -179,6 +180,7 @@ enum {
         TRACE_EVENT_FL_FILTERED         = (1 << TRACE_EVENT_FL_FILTERED_BIT),
         TRACE_EVENT_FL_RECORDED_CMD     = (1 << TRACE_EVENT_FL_RECORDED_CMD_BIT),
         TRACE_EVENT_FL_CAP_ANY          = (1 << TRACE_EVENT_FL_CAP_ANY_BIT),
+        TRACE_EVENT_FL_NO_SET_FILTER    = (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),
 };
 
 struct ftrace_event_call {