tracing: Kill destroy_call_preds()

Remove destroy_call_preds(). Its only caller, __trace_remove_event_call(),
can use free_event_filter() and nullify ->filter by hand.

Perhaps we could keep this trivial helper although imo it is pointless, but
then it should be static in trace_events.c.

Link: http://lkml.kernel.org/p/20140715184816.GA20495@redhat.com

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

include/linux/ftrace_event.h

@@ -404,7 +404,6 @@ enum event_trigger_type {
 	ETT_EVENT_ENABLE	= (1 << 3),
 };
 
-extern void destroy_call_preds(struct ftrace_event_call *call);
 extern int filter_match_preds(struct event_filter *filter, void *rec);
 
 extern int filter_check_discard(struct ftrace_event_file *file, void *rec,

kernel/trace/trace_events.c

@@ -1748,7 +1748,8 @@ static void __trace_remove_event_call(struct ftrace_event_call *call)
 {
 	event_remove(call);
 	trace_destroy_fields(call);
-	destroy_call_preds(call);
+	free_event_filter(call->filter);
+	call->filter = NULL;
 }
 
 static int probe_remove_event_call(struct ftrace_event_call *call)

kernel/trace/trace_events_filter.c

@@ -804,12 +804,6 @@ void free_event_filter(struct event_filter *filter)
 	__free_filter(filter);
 }
 
-void destroy_call_preds(struct ftrace_event_call *call)
-{
-	__free_filter(call->filter);
-	call->filter = NULL;
-}
-
 static struct event_filter *__alloc_filter(void)
 {
 	struct event_filter *filter;