Commit d75f717e authored by Steven Rostedt's avatar Steven Rostedt Committed by Steven Rostedt

tracing: Remove tracepoint sample code

The tracepoint sample code was used to teach developers how to
create their own tracepoints. But now the trace_events have been
added as a higher level that is used directly by developers today.

Only the trace_event code should use the tracepoint interface
directly and no new tracepoints should be added.

Besides, the example had a race condition with the use of the
 ->d_name.name dentry field, as pointed out by Al Viro.

Best just to remove the code so it wont be used by other developers.

Link: http://lkml.kernel.org/r/20130123225523.GY4939@ZenIV.linux.org.uk

Cc: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: 's avatarMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: 's avatarSteven Rostedt <rostedt@goodmis.org>
parent b736f48b
......@@ -5,12 +5,6 @@ menuconfig SAMPLES
if SAMPLES
config SAMPLE_TRACEPOINTS
tristate "Build tracepoints examples -- loadable modules only"
depends on TRACEPOINTS && m
help
This build tracepoints example modules.
config SAMPLE_TRACE_EVENTS
tristate "Build trace_events examples -- loadable modules only"
depends on EVENT_TRACING && m
......
# Makefile for Linux samples code
obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ tracepoints/ trace_events/ \
obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ trace_events/ \
hw_breakpoint/ kfifo/ kdb/ hidraw/ rpmsg/ seccomp/
# builds the tracepoint example kernel modules;
# then to use one (as root): insmod <module_name.ko>
obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-sample.o
obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample.o
obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample2.o
#ifndef _TP_SAMPLES_TRACE_H
#define _TP_SAMPLES_TRACE_H
#include <linux/proc_fs.h> /* for struct inode and struct file */
#include <linux/tracepoint.h>
DECLARE_TRACE(subsys_event,
TP_PROTO(struct inode *inode, struct file *file),
TP_ARGS(inode, file));
DECLARE_TRACE_NOARGS(subsys_eventb);
#endif
/*
* tracepoint-probe-sample.c
*
* sample tracepoint probes.
*/
#include <linux/module.h>
#include <linux/file.h>
#include <linux/dcache.h>
#include "tp-samples-trace.h"
/*
* Here the caller only guarantees locking for struct file and struct inode.
* Locking must therefore be done in the probe to use the dentry.
*/
static void probe_subsys_event(void *ignore,
struct inode *inode, struct file *file)
{
path_get(&file->f_path);
dget(file->f_path.dentry);
printk(KERN_INFO "Event is encountered with filename %s\n",
file->f_path.dentry->d_name.name);
dput(file->f_path.dentry);
path_put(&file->f_path);
}
static void probe_subsys_eventb(void *ignore)
{
printk(KERN_INFO "Event B is encountered\n");
}
static int __init tp_sample_trace_init(void)
{
int ret;
ret = register_trace_subsys_event(probe_subsys_event, NULL);
WARN_ON(ret);
ret = register_trace_subsys_eventb(probe_subsys_eventb, NULL);
WARN_ON(ret);
return 0;
}
module_init(tp_sample_trace_init);
static void __exit tp_sample_trace_exit(void)
{
unregister_trace_subsys_eventb(probe_subsys_eventb, NULL);
unregister_trace_subsys_event(probe_subsys_event, NULL);
tracepoint_synchronize_unregister();
}
module_exit(tp_sample_trace_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint Probes Samples");
/*
* tracepoint-probe-sample2.c
*
* 2nd sample tracepoint probes.
*/
#include <linux/module.h>
#include <linux/fs.h>
#include "tp-samples-trace.h"
/*
* Here the caller only guarantees locking for struct file and struct inode.
* Locking must therefore be done in the probe to use the dentry.
*/
static void probe_subsys_event(void *ignore,
struct inode *inode, struct file *file)
{
printk(KERN_INFO "Event is encountered with inode number %lu\n",
inode->i_ino);
}
static int __init tp_sample_trace_init(void)
{
int ret;
ret = register_trace_subsys_event(probe_subsys_event, NULL);
WARN_ON(ret);
return 0;
}
module_init(tp_sample_trace_init);
static void __exit tp_sample_trace_exit(void)
{
unregister_trace_subsys_event(probe_subsys_event, NULL);
tracepoint_synchronize_unregister();
}
module_exit(tp_sample_trace_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint Probes Samples");
/* tracepoint-sample.c
*
* Executes a tracepoint when /proc/tracepoint-sample is opened.
*
* (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
*
* This file is released under the GPLv2.
* See the file COPYING for more details.
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include "tp-samples-trace.h"
DEFINE_TRACE(subsys_event);
DEFINE_TRACE(subsys_eventb);
struct proc_dir_entry *pentry_sample;
static int my_open(struct inode *inode, struct file *file)
{
int i;
trace_subsys_event(inode, file);
for (i = 0; i < 10; i++)
trace_subsys_eventb();
return -EPERM;
}
static const struct file_operations mark_ops = {
.open = my_open,
.llseek = noop_llseek,
};
static int __init sample_init(void)
{
printk(KERN_ALERT "sample init\n");
pentry_sample = proc_create("tracepoint-sample", 0444, NULL,
&mark_ops);
if (!pentry_sample)
return -EPERM;
return 0;
}
static void __exit sample_exit(void)
{
printk(KERN_ALERT "sample exit\n");
remove_proc_entry("tracepoint-sample", NULL);
}
module_init(sample_init)
module_exit(sample_exit)
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mathieu Desnoyers");
MODULE_DESCRIPTION("Tracepoint sample");
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