tracing/filters: Add __field_ext() to TRACE_EVENT

Add __field_ext(), so a field can be assigned to a specific
filter_type, which matches a corresponding filter function.

For example, a later patch will allow this:
	__field_ext(const char *, str, FILTER_PTR_STR);

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A7B9272.6050709@cn.fujitsu.com>

[
  Fixed a -1 to FILTER_OTHER
  Forward ported to latest kernel.
]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h
index df5b085..0440bea 100644
--- a/include/linux/ftrace_event.h
+++ b/include/linux/ftrace_event.h
@@ -140,9 +140,16 @@
 					void *rec,
 					struct ring_buffer_event *event);
 
+enum {
+	FILTER_OTHER = 0,
+	FILTER_STATIC_STRING,
+	FILTER_DYN_STRING,
+};
+
 extern int trace_define_field(struct ftrace_event_call *call,
 			      const char *type, const char *name,
-			      int offset, int size, int is_signed);
+			      int offset, int size, int is_signed,
+			      int filter_type);
 extern int trace_define_common_fields(struct ftrace_event_call *call);
 
 #define is_signed_type(type)	(((type)(-1)) < 0)