tracing/filters: move preds into event_filter object

Create a new event_filter object, and move the pred-related members
out of the call and subsystem objects and into the filter object - the
details of the filter implementation don't need to be exposed in the
call and subsystem in any case, and it will also help make the new
parser implementation a little cleaner.

[ Impact: refactor trace-filter code to prepare for new features ]

Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: fweisbec@gmail.com
Cc: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <1240905887.6416.119.camel@tropicana>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index be4d3a4..1cd1f37 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -757,8 +757,7 @@
 
 	list_add(&system->list, &event_subsystems);
 
-	system->preds = NULL;
-	system->n_preds = 0;
+	system->filter = NULL;
 
 	entry = debugfs_create_file("filter", 0644, system->entry, system,
 				    &ftrace_subsystem_filter_fops);