1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2017 Joe Lawrence <joe.lawrence@redhat.com>
4  */
5 
6 /*
7  * livepatch-callbacks-busymod.c - (un)patching callbacks demo support module
8  *
9  *
10  * Purpose
11  * -------
12  *
13  * Simple module to demonstrate livepatch (un)patching callbacks.
14  *
15  *
16  * Usage
17  * -----
18  *
19  * This module is not intended to be standalone.  See the "Usage"
20  * section of livepatch-callbacks-mod.c.
21  */
22 
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/workqueue.h>
28 #include <linux/delay.h>
29 
30 static int sleep_secs;
31 module_param(sleep_secs, int, 0644);
32 MODULE_PARM_DESC(sleep_secs, "sleep_secs (default=0)");
33 
34 static void busymod_work_func(struct work_struct *work);
35 static DECLARE_DELAYED_WORK(work, busymod_work_func);
36 
37 static void busymod_work_func(struct work_struct *work)
38 {
39 	pr_info("%s, sleeping %d seconds ...\n", __func__, sleep_secs);
40 	msleep(sleep_secs * 1000);
41 	pr_info("%s exit\n", __func__);
42 }
43 
44 static int livepatch_callbacks_mod_init(void)
45 {
46 	pr_info("%s\n", __func__);
47 	schedule_delayed_work(&work,
48 		msecs_to_jiffies(1000 * 0));
49 	return 0;
50 }
51 
52 static void livepatch_callbacks_mod_exit(void)
53 {
54 	cancel_delayed_work_sync(&work);
55 	pr_info("%s\n", __func__);
56 }
57 
58 module_init(livepatch_callbacks_mod_init);
59 module_exit(livepatch_callbacks_mod_exit);
60 MODULE_LICENSE("GPL");
61