samples/livepatch/livepatch-callbacks-busymod.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright (C) 2017 Joe Lawrence <joe.lawrence@redhat.com>
0004  */
0005
0006 /*
0007  * livepatch-callbacks-busymod.c - (un)patching callbacks demo support module
0008  *
0009  *
0010  * Purpose
0011  * -------
0012  *
0013  * Simple module to demonstrate livepatch (un)patching callbacks.
0014  *
0015  *
0016  * Usage
0017  * -----
0018  *
0019  * This module is not intended to be standalone.  See the "Usage"
0020  * section of livepatch-callbacks-mod.c.
0021  */
0022
0023 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
0024
0025 #include <linux/module.h>
0026 #include <linux/kernel.h>
0027 #include <linux/workqueue.h>
0028 #include <linux/delay.h>
0029
0030 static int sleep_secs;
0031 module_param(sleep_secs, int, 0644);
0032 MODULE_PARM_DESC(sleep_secs, "sleep_secs (default=0)");
0033
0034 static void busymod_work_func(struct work_struct *work);
0035 static DECLARE_DELAYED_WORK(work, busymod_work_func);
0036
0037 static void busymod_work_func(struct work_struct *work)
0038 {
0039     pr_info("%s, sleeping %d seconds ...\n", __func__, sleep_secs);
0040     msleep(sleep_secs * 1000);
0041     pr_info("%s exit\n", __func__);
0042 }
0043
0044 static int livepatch_callbacks_mod_init(void)
0045 {
0046     pr_info("%s\n", __func__);
0047     schedule_delayed_work(&work,
0048         msecs_to_jiffies(1000 * 0));
0049     return 0;
0050 }
0051
0052 static void livepatch_callbacks_mod_exit(void)
0053 {
0054     cancel_delayed_work_sync(&work);
0055     pr_info("%s\n", __func__);
0056 }
0057
0058 module_init(livepatch_callbacks_mod_init);
0059 module_exit(livepatch_callbacks_mod_exit);
0060 MODULE_LICENSE("GPL");