tracing: Use class->reg() for all registering of events

Because kprobes and syscalls need special processing to register
events, the class->reg() method was created to handle the differences.

But instead of creating a default ->reg for perf and ftrace events,
the code was scattered with:

	if (class->reg)
		class->reg();
	else
		default_reg();

This is messy and can also lead to bugs.

This patch cleans up this code and creates a default reg() entry for
the events allowing for the code to directly call the class->reg()
without the condition.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 3 insertions, 16 deletions

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 6053982dc302..23751659582e 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -54,13 +54,7 @@ static int perf_trace_event_init(struct ftrace_event_call *tp_event,
                 }
         }
 
-        if (tp_event->class->reg)
-                ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER);
-        else
-                ret = tracepoint_probe_register(tp_event->name,
-                                                tp_event->class->perf_probe,
-                                                tp_event);
-
+        ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER);
         if (ret)
                 goto fail;
 
@@ -94,9 +88,7 @@ int perf_trace_init(struct perf_event *p_event)
         mutex_lock(&event_mutex);
         list_for_each_entry(tp_event, &ftrace_events, list) {
                 if (tp_event->event.type == event_id &&
-                    tp_event->class &&
-                    (tp_event->class->perf_probe ||
-                     tp_event->class->reg) &&
+                    tp_event->class && tp_event->class->reg &&
                     try_module_get(tp_event->mod)) {
                         ret = perf_trace_event_init(tp_event, p_event);
                         break;
@@ -136,12 +128,7 @@ void perf_trace_destroy(struct perf_event *p_event)
         if (--tp_event->perf_refcount > 0)
                 goto out;
 
-        if (tp_event->class->reg)
-                tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER);
-        else
-                tracepoint_probe_unregister(tp_event->name,
-                                            tp_event->class->perf_probe,
-                                            tp_event);
+        tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER);
 
         /*
          * Ensure our callback won't be called anymore. See