[for-next][PATCH 17/17] tracing: Move the tracing selftest code into its own function

From: Steven Rostedt
Date: Thu Mar 07 2013 - 22:10:34 EST


From: "Steven Rostedt (Red Hat)" <srostedt@xxxxxxxxxx>

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@xxxxxxxxxxx>
---
kernel/trace/trace.c | 124 ++++++++++++++++++++++++++++----------------------
1 file changed, 69 insertions(+), 55 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index c15ba8b..86a6d7a 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -817,6 +817,72 @@ 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
@@ -862,61 +928,9 @@ 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;
--
1.7.10.4


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