tracing/ftrace: change the type of the init() callback
Impact: extend the ->init() method with the ability to fail
This bring a way to know if the initialization of a tracer successed.
A tracer must return 0 on success and a traditional error (ie:
-ENOMEM) if it fails.
If a tracer fails to init, it is free to print a detailed warn. The
tracing api will not and switch to a new tracer will just return the
error from the init callback.
Note: this will be used for the return tracer.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 5cb64ea..88c8eb7 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -71,6 +71,11 @@
return ret;
}
+static inline void warn_failed_init_tracer(struct tracer *trace, int init_ret)
+{
+ printk(KERN_WARNING "Failed to init %s tracer, init returned %d\n",
+ trace->name, init_ret);
+}
#ifdef CONFIG_FUNCTION_TRACER
#ifdef CONFIG_DYNAMIC_FTRACE
@@ -111,7 +116,11 @@
ftrace_set_filter(func_name, strlen(func_name), 1);
/* enable tracing */
- trace->init(tr);
+ ret = trace->init(tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ goto out;
+ }
/* Sleep for a 1/10 of a second */
msleep(100);
@@ -181,7 +190,12 @@
ftrace_enabled = 1;
tracer_enabled = 1;
- trace->init(tr);
+ ret = trace->init(tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ goto out;
+ }
+
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */
@@ -223,7 +237,12 @@
int ret;
/* start the tracing */
- trace->init(tr);
+ ret = trace->init(tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ return ret;
+ }
+
/* reset the max latency */
tracing_max_latency = 0;
/* disable interrupts for a bit */
@@ -272,7 +291,12 @@
}
/* start the tracing */
- trace->init(tr);
+ ret = trace->init(tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ return ret;
+ }
+
/* reset the max latency */
tracing_max_latency = 0;
/* disable preemption for a bit */
@@ -321,7 +345,11 @@
}
/* start the tracing */
- trace->init(tr);
+ ret = trace->init(tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ goto out;
+ }
/* reset the max latency */
tracing_max_latency = 0;
@@ -449,7 +477,12 @@
wait_for_completion(&isrt);
/* start the tracing */
- trace->init(tr);
+ ret = trace->init(tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ return ret;
+ }
+
/* reset the max latency */
tracing_max_latency = 0;
@@ -505,7 +538,12 @@
int ret;
/* start the tracing */
- trace->init(tr);
+ ret = trace->init(tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ return ret;
+ }
+
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */
@@ -532,7 +570,12 @@
int ret;
/* start the tracing */
- trace->init(tr);
+ ret = trace->init(tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ return 0;
+ }
+
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */
@@ -554,7 +597,12 @@
int ret;
/* start the tracing */
- trace->init(tr);
+ ret = trace->init(tr);
+ if (ret) {
+ warn_failed_init_tracer(trace, ret);
+ return ret;
+ }
+
/* Sleep for a 1/10 of a second */
msleep(100);
/* stop the tracing. */