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tracing: Use class->reg() for all registering of events

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Because kprobes and syscalls need special processing to register
events, the class->reg() method was created to handle the differences.

But instead of creating a default ->reg for perf and ftrace events,
the code was scattered with:

	if (class->reg)
		class->reg();
	else
		default_reg();

This is messy and can also lead to bugs.

This patch cleans up this code and creates a default reg() entry for
the events allowing for the code to directly call the class->reg()
without the condition.

Reported-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2010-06-08 11:22:06 -04:00 committed by Steven Rostedt
parent d62f85d1e2
commit a1d0ce8213
4 changed files with 44 additions and 35 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
include/linux/ftrace_event.h
View file

@ -146,6 +146,9 @@ struct ftrace_event_class {
int (*raw_init)(struct ftrace_event_call *);
};
extern int ftrace_event_reg(struct ftrace_event_call *event,
enum trace_reg type);
enum {
TRACE_EVENT_FL_ENABLED_BIT,
TRACE_EVENT_FL_FILTERED_BIT,

2
include/trace/ftrace.h
View file

@ -439,6 +439,7 @@ static inline notrace int ftrace_get_offsets_##call( \
* .fields = LIST_HEAD_INIT(event_class_##call.fields),
* .raw_init = trace_event_raw_init,
* .probe = ftrace_raw_event_##call,
* .reg = ftrace_event_reg,
* };
*
* static struct ftrace_event_call __used
@ -567,6 +568,7 @@ static struct ftrace_event_class __used event_class_##call = { \
.fields = LIST_HEAD_INIT(event_class_##call.fields),\
.raw_init = trace_event_raw_init, \
.probe = ftrace_raw_event_##call, \
.reg = ftrace_event_reg, \
_TRACE_PERF_INIT(call) \
};

19
kernel/trace/trace_event_perf.c
View file

@ -54,13 +54,7 @@ static int perf_trace_event_init(struct ftrace_event_call *tp_event,
}
}
if (tp_event->class->reg)
ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER);
else
ret = tracepoint_probe_register(tp_event->name,
tp_event->class->perf_probe,
tp_event);
ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER);
if (ret)
goto fail;
@ -94,9 +88,7 @@ int perf_trace_init(struct perf_event *p_event)
mutex_lock(&event_mutex);
list_for_each_entry(tp_event, &ftrace_events, list) {
if (tp_event->event.type == event_id &&
tp_event->class &&
(tp_event->class->perf_probe ||
tp_event->class->reg) &&
tp_event->class && tp_event->class->reg &&
try_module_get(tp_event->mod)) {
ret = perf_trace_event_init(tp_event, p_event);
break;
@ -136,12 +128,7 @@ void perf_trace_destroy(struct perf_event *p_event)
if (--tp_event->perf_refcount > 0)
goto out;
if (tp_event->class->reg)
tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER);
else
tracepoint_probe_unregister(tp_event->name,
tp_event->class->perf_probe,
tp_event);
tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER);
/*
* Ensure our callback won't be called anymore. See

55
kernel/trace/trace_events.c
View file

@ -141,6 +141,35 @@ int trace_event_raw_init(struct ftrace_event_call *call)
}
EXPORT_SYMBOL_GPL(trace_event_raw_init);
int ftrace_event_reg(struct ftrace_event_call *call, enum trace_reg type)
{
switch (type) {
case TRACE_REG_REGISTER:
return tracepoint_probe_register(call->name,
call->class->probe,
call);
case TRACE_REG_UNREGISTER:
tracepoint_probe_unregister(call->name,
call->class->probe,
call);
return 0;
#ifdef CONFIG_PERF_EVENTS
case TRACE_REG_PERF_REGISTER:
return tracepoint_probe_register(call->name,
call->class->perf_probe,
call);
case TRACE_REG_PERF_UNREGISTER:
tracepoint_probe_unregister(call->name,
call->class->perf_probe,
call);
return 0;
#endif
}
return 0;
}
EXPORT_SYMBOL_GPL(ftrace_event_reg);
static int ftrace_event_enable_disable(struct ftrace_event_call *call,
int enable)
{
@ -151,23 +180,13 @@ static int ftrace_event_enable_disable(struct ftrace_event_call *call,
if (call->flags & TRACE_EVENT_FL_ENABLED) {
call->flags &= ~TRACE_EVENT_FL_ENABLED;
tracing_stop_cmdline_record();
if (call->class->reg)
call->class->reg(call, TRACE_REG_UNREGISTER);
else
tracepoint_probe_unregister(call->name,
call->class->probe,
call);
call->class->reg(call, TRACE_REG_UNREGISTER);
}
break;
case 1:
if (!(call->flags & TRACE_EVENT_FL_ENABLED)) {
tracing_start_cmdline_record();
if (call->class->reg)
ret = call->class->reg(call, TRACE_REG_REGISTER);
else
ret = tracepoint_probe_register(call->name,
call->class->probe,
call);
ret = call->class->reg(call, TRACE_REG_REGISTER);
if (ret) {
tracing_stop_cmdline_record();
pr_info("event trace: Could not enable event "
@ -205,8 +224,7 @@ static int __ftrace_set_clr_event(const char *match, const char *sub,
mutex_lock(&event_mutex);
list_for_each_entry(call, &ftrace_events, list) {
if (!call->name || !call->class ||
(!call->class->probe && !call->class->reg))
if (!call->name || !call->class || !call->class->reg)
continue;
if (match &&
@ -332,7 +350,7 @@ t_next(struct seq_file *m, void *v, loff_t *pos)
* The ftrace subsystem is for showing formats only.
* They can not be enabled or disabled via the event files.
*/
if (call->class && (call->class->probe || call->class->reg))
if (call->class && call->class->reg)
return call;
}
@ -485,8 +503,7 @@ system_enable_read(struct file *filp, char __user *ubuf, size_t cnt,
mutex_lock(&event_mutex);
list_for_each_entry(call, &ftrace_events, list) {
if (!call->name || !call->class ||
(!call->class->probe && !call->class->reg))
if (!call->name || !call->class || !call->class->reg)
continue;
if (system && strcmp(call->class->system, system) != 0)
@ -977,12 +994,12 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events,
return -1;
}
if (call->class->probe || call->class->reg)
if (call->class->reg)
trace_create_file("enable", 0644, call->dir, call,
enable);
#ifdef CONFIG_PERF_EVENTS
if (call->event.type && (call->class->perf_probe || call->class->reg))
if (call->event.type && call->class->reg)
trace_create_file("id", 0444, call->dir, call,
id);
#endif