Commit 1c80025a authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
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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: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent e6e7a65a
......@@ -2638,8 +2638,11 @@ static int tracing_set_tracer(char *buf)
current_trace->reset(tr);
current_trace = t;
if (t->init)
t->init(tr);
if (t->init) {
ret = t->init(tr);
if (ret)
goto out;
}
trace_branch_enable(tr);
out:
......
......@@ -264,7 +264,8 @@ enum print_line_t {
*/
struct tracer {
const char *name;
void (*init)(struct trace_array *tr);
/* Your tracer should raise a warning if init fails */
int (*init)(struct trace_array *tr);
void (*reset)(struct trace_array *tr);
void (*start)(struct trace_array *tr);
void (*stop)(struct trace_array *tr);
......
......@@ -47,7 +47,7 @@ static void reset_boot_trace(struct trace_array *tr)
tracing_reset(tr, cpu);
}
static void boot_trace_init(struct trace_array *tr)
static int boot_trace_init(struct trace_array *tr)
{
int cpu;
boot_trace = tr;
......@@ -56,6 +56,7 @@ static void boot_trace_init(struct trace_array *tr)
tracing_reset(tr, cpu);
tracing_sched_switch_assign_trace(tr);
return 0;
}
static enum print_line_t
......
......@@ -125,7 +125,7 @@ static void stop_branch_trace(struct trace_array *tr)
disable_branch_tracing();
}
static void branch_trace_init(struct trace_array *tr)
static int branch_trace_init(struct trace_array *tr)
{
int cpu;
......@@ -133,6 +133,7 @@ static void branch_trace_init(struct trace_array *tr)
tracing_reset(tr, cpu);
start_branch_trace(tr);
return 0;
}
static void branch_trace_reset(struct trace_array *tr)
......
......@@ -42,9 +42,10 @@ static void stop_function_trace(struct trace_array *tr)
tracing_stop_cmdline_record();
}
static void function_trace_init(struct trace_array *tr)
static int function_trace_init(struct trace_array *tr)
{
start_function_trace(tr);
return 0;
}
static void function_trace_reset(struct trace_array *tr)
......
......@@ -24,13 +24,14 @@ static void stop_return_trace(struct trace_array *tr)
unregister_ftrace_return();
}
static void return_trace_init(struct trace_array *tr)
static int return_trace_init(struct trace_array *tr)
{
int cpu;
for_each_online_cpu(cpu)
tracing_reset(tr, cpu);
start_return_trace(tr);
return 0;
}
static void return_trace_reset(struct trace_array *tr)
......
......@@ -416,11 +416,12 @@ static void irqsoff_tracer_close(struct trace_iterator *iter)
}
#ifdef CONFIG_IRQSOFF_TRACER
static void irqsoff_tracer_init(struct trace_array *tr)
static int irqsoff_tracer_init(struct trace_array *tr)
{
trace_type = TRACER_IRQS_OFF;
__irqsoff_tracer_init(tr);
return 0;
}
static struct tracer irqsoff_tracer __read_mostly =
{
......@@ -442,11 +443,12 @@ static struct tracer irqsoff_tracer __read_mostly =
#endif
#ifdef CONFIG_PREEMPT_TRACER
static void preemptoff_tracer_init(struct trace_array *tr)
static int preemptoff_tracer_init(struct trace_array *tr)
{
trace_type = TRACER_PREEMPT_OFF;
__irqsoff_tracer_init(tr);
return 0;
}
static struct tracer preemptoff_tracer __read_mostly =
......@@ -471,11 +473,12 @@ static struct tracer preemptoff_tracer __read_mostly =
#if defined(CONFIG_IRQSOFF_TRACER) && \
defined(CONFIG_PREEMPT_TRACER)
static void preemptirqsoff_tracer_init(struct trace_array *tr)
static int preemptirqsoff_tracer_init(struct trace_array *tr)
{
trace_type = TRACER_IRQS_OFF | TRACER_PREEMPT_OFF;
__irqsoff_tracer_init(tr);
return 0;
}
static struct tracer preemptirqsoff_tracer __read_mostly =
......
......@@ -30,13 +30,14 @@ static void mmio_reset_data(struct trace_array *tr)
tracing_reset(tr, cpu);
}
static void mmio_trace_init(struct trace_array *tr)
static int mmio_trace_init(struct trace_array *tr)
{
pr_debug("in %s\n", __func__);
mmio_trace_array = tr;
mmio_reset_data(tr);
enable_mmiotrace();
return 0;
}
static void mmio_trace_reset(struct trace_array *tr)
......
......@@ -24,7 +24,7 @@ static void stop_nop_trace(struct trace_array *tr)
/* Nothing to do! */
}
static void nop_trace_init(struct trace_array *tr)
static int nop_trace_init(struct trace_array *tr)
{
int cpu;
ctx_trace = tr;
......@@ -33,6 +33,7 @@ static void nop_trace_init(struct trace_array *tr)
tracing_reset(tr, cpu);
start_nop_trace(tr);
return 0;
}
static void nop_trace_reset(struct trace_array *tr)
......
......@@ -206,10 +206,11 @@ static void stop_sched_trace(struct trace_array *tr)
tracing_stop_sched_switch_record();
}
static void sched_switch_trace_init(struct trace_array *tr)
static int sched_switch_trace_init(struct trace_array *tr)
{
ctx_trace = tr;
start_sched_trace(tr);
return 0;
}
static void sched_switch_trace_reset(struct trace_array *tr)
......
......@@ -331,10 +331,11 @@ static void stop_wakeup_tracer(struct trace_array *tr)
unregister_trace_sched_wakeup(probe_wakeup);
}
static void wakeup_tracer_init(struct trace_array *tr)
static int wakeup_tracer_init(struct trace_array *tr)
{
wakeup_trace = tr;
start_wakeup_tracer(tr);
return 0;
}
static void wakeup_tracer_reset(struct trace_array *tr)
......
......@@ -71,6 +71,11 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count)
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 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
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 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr)
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 @@ trace_selftest_startup_irqsoff(struct tracer *trace, struct trace_array *tr)
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 @@ trace_selftest_startup_preemptoff(struct tracer *trace, struct trace_array *tr)
}
/* 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 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array *
}
/* 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 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr)
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 @@ trace_selftest_startup_sched_switch(struct tracer *trace, struct trace_array *tr
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 @@ trace_selftest_startup_sysprof(struct tracer *trace, struct trace_array *tr)
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 @@ trace_selftest_startup_branch(struct tracer *trace, struct trace_array *tr)
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. */
......
......@@ -261,11 +261,12 @@ static void stop_stack_trace(struct trace_array *tr)
mutex_unlock(&sample_timer_lock);
}
static void stack_trace_init(struct trace_array *tr)
static int stack_trace_init(struct trace_array *tr)
{
sysprof_trace = tr;
start_stack_trace(tr);
return 0;
}
static void stack_trace_reset(struct trace_array *tr)
......
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