1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2019 Eric van Gyzen
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 * $FreeBSD$
28 */
29
30/*
31 * Free a pending callout.  This was useful for testing the
32 * "show callout_last" ddb command.
33 */
34
35#include <sys/param.h>
36#include <sys/conf.h>
37#include <sys/kernel.h>
38#include <sys/lock.h>
39#include <sys/module.h>
40#include <sys/mutex.h>
41#include <sys/systm.h>
42
43static struct callout callout_free;
44static struct mtx callout_free_mutex;
45static int callout_free_arg;
46
47static void
48callout_free_func(void *arg)
49{
50	printf("squirrel!\n");
51	mtx_destroy(&callout_free_mutex);
52	memset(&callout_free, 'C', sizeof(callout_free));
53}
54
55static int
56callout_free_load(module_t mod, int cmd, void *arg)
57{
58	int error;
59
60	switch (cmd) {
61	case MOD_LOAD:
62		mtx_init(&callout_free_mutex, "callout_free", NULL, MTX_DEF);
63		/*
64		 * Do not pass CALLOUT_RETURNUNLOCKED so the callout
65		 * subsystem will unlock the "destroyed" mutex.
66		 */
67		callout_init_mtx(&callout_free, &callout_free_mutex, 0);
68		printf("callout_free_func = %p\n", callout_free_func);
69		printf("callout_free_arg = %p\n", &callout_free_arg);
70		callout_reset(&callout_free, hz/10, callout_free_func,
71		    &callout_free_arg);
72		error = 0;
73		break;
74
75	case MOD_UNLOAD:
76		error = 0;
77		break;
78
79	default:
80		error = EOPNOTSUPP;
81		break;
82	}
83
84	return (error);
85}
86
87DEV_MODULE(callout_free, callout_free_load, NULL);
88