tracing: Move the tracing selftest code into its own function
authorSteven Rostedt (Red Hat) <srostedt@redhat.com>
Thu, 7 Mar 2013 16:10:56 +0000 (11:10 -0500)
committerSteven Rostedt <rostedt@goodmis.org>
Fri, 15 Mar 2013 04:35:53 +0000 (00:35 -0400)
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

index 307524d784ecbeda1a7a0ca05178dbb44f8faed1..57b4220d96a9d14244441b192b1735b8735b7001 100644 (file)
@@ -818,6 +818,72 @@ static void default_wait_pipe(struct trace_iterator *iter)
        ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file);
 }
 
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+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.
+        * Here we reset the trace buffer, and set the current
+        * tracer to be this tracer. The tracer can then run some
+        * internal tracing to verify that everything is in order.
+        * If we fail, we do not register this tracer.
+        */
+       tracing_reset_online_cpus(&tr->trace_buffer);
+
+       tr->current_trace = type;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+       if (type->use_max_tr) {
+               /* If we expanded the buffers, make sure the max is expanded too */
+               if (ring_buffer_expanded)
+                       ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
+                                          RING_BUFFER_ALL_CPUS);
+               tr->allocated_snapshot = true;
+       }
+#endif
+
+       /* the test is responsible for initializing and enabling */
+       pr_info("Testing tracer %s: ", type->name);
+       ret = type->selftest(type, tr);
+       /* the test is responsible for resetting too */
+       tr->current_trace = saved_tracer;
+       if (ret) {
+               printk(KERN_CONT "FAILED!\n");
+               /* Add the warning after printing 'FAILED' */
+               WARN_ON(1);
+               return -1;
+       }
+       /* Only reset on passing, to avoid touching corrupted buffers */
+       tracing_reset_online_cpus(&tr->trace_buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+       if (type->use_max_tr) {
+               tr->allocated_snapshot = false;
+
+               /* Shrink the max buffer again */
+               if (ring_buffer_expanded)
+                       ring_buffer_resize(tr->max_buffer.buffer, 1,
+                                          RING_BUFFER_ALL_CPUS);
+       }
+#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
@@ -863,61 +929,9 @@ int register_tracer(struct tracer *type)
        if (!type->wait_pipe)
                type->wait_pipe = default_wait_pipe;
 
-
-#ifdef CONFIG_FTRACE_STARTUP_TEST
-       if (type->selftest && !tracing_selftest_disabled) {
-               struct trace_array *tr = &global_trace;
-               struct tracer *saved_tracer = tr->current_trace;
-
-               /*
-                * Run a selftest on this tracer.
-                * Here we reset the trace buffer, and set the current
-                * tracer to be this tracer. The tracer can then run some
-                * internal tracing to verify that everything is in order.
-                * If we fail, we do not register this tracer.
-                */
-               tracing_reset_online_cpus(&tr->trace_buffer);
-
-               tr->current_trace = type;
-
-#ifdef CONFIG_TRACER_MAX_TRACE
-               if (type->use_max_tr) {
-                       /* If we expanded the buffers, make sure the max is expanded too */
-                       if (ring_buffer_expanded)
-                               ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
-                                                  RING_BUFFER_ALL_CPUS);
-                       tr->allocated_snapshot = true;
-               }
-#endif
-
-               /* the test is responsible for initializing and enabling */
-               pr_info("Testing tracer %s: ", type->name);
-               ret = type->selftest(type, tr);
-               /* the test is responsible for resetting too */
-               tr->current_trace = saved_tracer;
-               if (ret) {
-                       printk(KERN_CONT "FAILED!\n");
-                       /* Add the warning after printing 'FAILED' */
-                       WARN_ON(1);
-                       goto out;
-               }
-               /* Only reset on passing, to avoid touching corrupted buffers */
-               tracing_reset_online_cpus(&tr->trace_buffer);
-
-#ifdef CONFIG_TRACER_MAX_TRACE
-               if (type->use_max_tr) {
-                       tr->allocated_snapshot = false;
-
-                       /* Shrink the max buffer again */
-                       if (ring_buffer_expanded)
-                               ring_buffer_resize(tr->max_buffer.buffer, 1,
-                                                  RING_BUFFER_ALL_CPUS);
-               }
-#endif
-
-               printk(KERN_CONT "PASSED\n");
-       }
-#endif
+       ret = run_tracer_selftest(type);
+       if (ret < 0)
+               goto out;
 
        type->next = trace_types;
        trace_types = type;