tracing: Let tracepoints have data passed to tracepoint callbacks
[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(void *ignore,
17                                struct inode *inode, struct file *file)
18 {
19         path_get(&file->f_path);
20         dget(file->f_path.dentry);
21         printk(KERN_INFO "Event is encountered with filename %s\n",
22                 file->f_path.dentry->d_name.name);
23         dput(file->f_path.dentry);
24         path_put(&file->f_path);
25 }
26
27 static void probe_subsys_eventb(void *ignore)
28 {
29         printk(KERN_INFO "Event B is encountered\n");
30 }
31
32 static int __init tp_sample_trace_init(void)
33 {
34         int ret;
35
36         ret = register_trace_subsys_event(probe_subsys_event, NULL);
37         WARN_ON(ret);
38         ret = register_trace_subsys_eventb(probe_subsys_eventb, NULL);
39         WARN_ON(ret);
40
41         return 0;
42 }
43
44 module_init(tp_sample_trace_init);
45
46 static void __exit tp_sample_trace_exit(void)
47 {
48         unregister_trace_subsys_eventb(probe_subsys_eventb, NULL);
49         unregister_trace_subsys_event(probe_subsys_event, NULL);
50         tracepoint_synchronize_unregister();
51 }
52
53 module_exit(tp_sample_trace_exit);
54
55 MODULE_LICENSE("GPL");
56 MODULE_AUTHOR("Mathieu Desnoyers");
57 MODULE_DESCRIPTION("Tracepoint Probes Samples");