tracing: tracepoints, samples
[linux-2.6.git] / samples / tracepoints / tracepoint-probe-sample.c
1 /*
2  * tracepoint-probe-sample.c
3  *
4  * sample tracepoint probes.
5  */
6
7 #include <linux/module.h>
8 #include <linux/file.h>
9 #include <linux/dcache.h>
10 #include "tp-samples-trace.h"
11
12 /*
13  * Here the caller only guarantees locking for struct file and struct inode.
14  * Locking must therefore be done in the probe to use the dentry.
15  */
16 static void probe_subsys_event(struct inode *inode, struct file *file)
17 {
18         path_get(&file->f_path);
19         dget(file->f_path.dentry);
20         printk(KERN_INFO "Event is encountered with filename %s\n",
21                 file->f_path.dentry->d_name.name);
22         dput(file->f_path.dentry);
23         path_put(&file->f_path);
24 }
25
26 static void probe_subsys_eventb(void)
27 {
28         printk(KERN_INFO "Event B is encountered\n");
29 }
30
31 int __init tp_sample_trace_init(void)
32 {
33         int ret;
34
35         ret = register_trace_subsys_event(probe_subsys_event);
36         WARN_ON(ret);
37         ret = register_trace_subsys_eventb(probe_subsys_eventb);
38         WARN_ON(ret);
39
40         return 0;
41 }
42
43 module_init(tp_sample_trace_init);
44
45 void __exit tp_sample_trace_exit(void)
46 {
47         unregister_trace_subsys_eventb(probe_subsys_eventb);
48         unregister_trace_subsys_event(probe_subsys_event);
49 }
50
51 module_exit(tp_sample_trace_exit);
52
53 MODULE_LICENSE("GPL");
54 MODULE_AUTHOR("Mathieu Desnoyers");
55 MODULE_DESCRIPTION("Tracepoint Probes Samples");