tools lib traceevent: Add destructor for format_field

Move the calls that frees the resources allocated for a struct format_field to
a separate routine.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1426790181-19118-1-git-send-email-dsahern@gmail.com
[ Split this part from a larger patch, added pevent_ prefix as requested by Steven ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/traceevent/event-parse.c

@@ -6228,15 +6228,20 @@ void pevent_ref(struct pevent *pevent)
 	pevent->ref_count++;
 }
 
+void pevent_free_format_field(struct format_field *field)
+{
+	free(field->type);
+	free(field->name);
+	free(field);
+}
+
 static void free_format_fields(struct format_field *field)
 {
 	struct format_field *next;
 
 	while (field) {
 		next = field->next;
-		free(field->type);
-		free(field->name);
-		free(field);
+		pevent_free_format_field(field);
 		field = next;
 	}
 }

tools/lib/traceevent/event-parse.h

@@ -619,6 +619,7 @@ enum pevent_errno pevent_parse_format(struct pevent *pevent,
 				      const char *buf,
 				      unsigned long size, const char *sys);
 void pevent_free_format(struct event_format *event);
+void pevent_free_format_field(struct format_field *field);
 
 void *pevent_get_field_raw(struct trace_seq *s, struct event_format *event,
 			   const char *name, struct pevent_record *record,