tracing: Move the tracing selftest code into its own function

Move the tracing startup selftest code into its own function and
when not enabled, always have that function succeed.

This makes the register_tracer() function much more readable.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.c

@@ -818,56 +818,15 @@ static void default_wait_pipe(struct trace_iterator *iter)
 	ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file);
 }
 
-/**
- * register_tracer - register a tracer with the ftrace system.
- * @type - the plugin for the tracer
- *
- * Register a new plugin tracer.
- */
-int register_tracer(struct tracer *type)
-{
-	struct tracer *t;
-	int ret = 0;
-
-	if (!type->name) {
-		pr_info("Tracer must have a name\n");
-		return -1;
-	}
-
-	if (strlen(type->name) >= MAX_TRACER_SIZE) {
-		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
-		return -1;
-	}
-
-	mutex_lock(&trace_types_lock);
-
-	tracing_selftest_running = true;
-
-	for (t = trace_types; t; t = t->next) {
-		if (strcmp(type->name, t->name) == 0) {
-			/* already found */
-			pr_info("Tracer %s already registered\n",
-				type->name);
-			ret = -1;
-			goto out;
-		}
-	}
-
-	if (!type->set_flag)
-		type->set_flag = &dummy_set_flag;
-	if (!type->flags)
-		type->flags = &dummy_tracer_flags;
-	else
-		if (!type->flags->opts)
-			type->flags->opts = dummy_tracer_opt;
-	if (!type->wait_pipe)
-		type->wait_pipe = default_wait_pipe;
-
-
 #ifdef CONFIG_FTRACE_STARTUP_TEST
-	if (type->selftest && !tracing_selftest_disabled) {
+static int run_tracer_selftest(struct tracer *type)
+{
 	struct trace_array *tr = &global_trace;
 	struct tracer *saved_tracer = tr->current_trace;
+	int ret;
+
+	if (!type->selftest || tracing_selftest_disabled)
+		return 0;
 
 	/*
 	 * Run a selftest on this tracer.
@@ -899,7 +858,7 @@ int register_tracer(struct tracer *type)
 		printk(KERN_CONT "FAILED!\n");
 		/* Add the warning after printing 'FAILED' */
 		WARN_ON(1);
-			goto out;
+		return -1;
 	}
 	/* Only reset on passing, to avoid touching corrupted buffers */
 	tracing_reset_online_cpus(&tr->trace_buffer);
@@ -916,8 +875,63 @@ int register_tracer(struct tracer *type)
 #endif
 
 	printk(KERN_CONT "PASSED\n");
+	return 0;
+}
+#else
+static inline int run_tracer_selftest(struct tracer *type)
+{
+	return 0;
+}
+#endif /* CONFIG_FTRACE_STARTUP_TEST */
+
+/**
+ * register_tracer - register a tracer with the ftrace system.
+ * @type - the plugin for the tracer
+ *
+ * Register a new plugin tracer.
+ */
+int register_tracer(struct tracer *type)
+{
+	struct tracer *t;
+	int ret = 0;
+
+	if (!type->name) {
+		pr_info("Tracer must have a name\n");
+		return -1;
 	}
-#endif
+
+	if (strlen(type->name) >= MAX_TRACER_SIZE) {
+		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
+		return -1;
+	}
+
+	mutex_lock(&trace_types_lock);
+
+	tracing_selftest_running = true;
+
+	for (t = trace_types; t; t = t->next) {
+		if (strcmp(type->name, t->name) == 0) {
+			/* already found */
+			pr_info("Tracer %s already registered\n",
+				type->name);
+			ret = -1;
+			goto out;
+		}
+	}
+
+	if (!type->set_flag)
+		type->set_flag = &dummy_set_flag;
+	if (!type->flags)
+		type->flags = &dummy_tracer_flags;
+	else
+		if (!type->flags->opts)
+			type->flags->opts = dummy_tracer_opt;
+	if (!type->wait_pipe)
+		type->wait_pipe = default_wait_pipe;
+
+	ret = run_tracer_selftest(type);
+	if (ret < 0)
+		goto out;
 
 	type->next = trace_types;
 	trace_types = type;