tracing: Remove test of NULL define_fields callback

Every event (or event class) has it's define_fields callback,
so the test is redundant.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BFA37BC.8080707@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace_events.c

@@ -987,7 +987,6 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
 		 		  id);
 #endif
 
-	if (call->class->define_fields) {
 	/*
 	 * Other events may have the same class. Only update
 	 * the fields if they are not already defined.
@@ -1003,7 +1002,6 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
 	}
 	trace_create_file("filter", 0644, call->dir, call,
 			  filter);
-	}
 
 	trace_create_file("format", 0444, call->dir, call,
 			  format);

kernel/trace/trace_events_filter.c

@@ -639,9 +639,6 @@ static int init_subsystem_preds(struct event_subsystem *system)
 	int err;
 
 	list_for_each_entry(call, &ftrace_events, list) {
-		if (!call->class || !call->class->define_fields)
-			continue;
-
 		if (strcmp(call->class->system, system->name) != 0)
 			continue;
 
@@ -658,9 +655,6 @@ static void filter_free_subsystem_preds(struct event_subsystem *system)
 	struct ftrace_event_call *call;
 
 	list_for_each_entry(call, &ftrace_events, list) {
-		if (!call->class || !call->class->define_fields)
-			continue;
-
 		if (strcmp(call->class->system, system->name) != 0)
 			continue;
 
@@ -1263,9 +1257,6 @@ static int replace_system_preds(struct event_subsystem *system,
 	list_for_each_entry(call, &ftrace_events, list) {
 		struct event_filter *filter = call->filter;
 
-		if (!call->class || !call->class->define_fields)
-			continue;
-
 		if (strcmp(call->class->system, system->name) != 0)
 			continue;