1/*	$OpenBSD: subr_xxx.c,v 1.17 2019/05/17 03:53:08 visa Exp $	*/
2/*	$NetBSD: subr_xxx.c,v 1.10 1996/02/04 02:16:51 christos Exp $	*/
3
4/*
5 * Copyright (c) 1982, 1986, 1991, 1993
6 *	The Regents of the University of California.  All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 *	@(#)subr_xxx.c	8.1 (Berkeley) 6/10/93
33 */
34
35/*
36 * Miscellaneous trivial functions, including many
37 * that are often inline-expanded or done in assembler.
38 */
39#include <sys/param.h>
40#include <sys/systm.h>
41#include <sys/conf.h>
42#include <sys/smr.h>
43
44
45/*
46 * Unsupported device function (e.g. writing to read-only device).
47 */
48int
49enodev(void)
50{
51
52	return (ENODEV);
53}
54
55/*
56 * Unconfigured device function; driver not configured.
57 */
58int
59enxio(void)
60{
61
62	return (ENXIO);
63}
64
65/*
66 * Unsupported ioctl function.
67 */
68int
69enoioctl(void)
70{
71
72	return (ENOTTY);
73}
74
75/*
76 * Unsupported system function.
77 * This is used for an otherwise-reasonable operation
78 * that is not supported by the current system binary.
79 */
80int
81enosys(void)
82{
83
84	return (ENOSYS);
85}
86
87/*
88 * Return error for operation not supported
89 * on a specific object or file type.
90 */
91int
92eopnotsupp(void *v)
93{
94
95	return (EOPNOTSUPP);
96}
97
98/*
99 * Generic null operation, always returns success.
100 */
101int
102nullop(void *v)
103{
104
105	return (0);
106}
107
108struct bdevsw *
109bdevsw_lookup(dev_t dev)
110{
111	return (&bdevsw[major(dev)]);
112}
113
114struct cdevsw *
115cdevsw_lookup(dev_t dev)
116{
117	return (&cdevsw[major(dev)]);
118}
119
120/*
121 * Convert a character device number to a block device number.
122 */
123dev_t
124chrtoblk(dev_t dev)
125{
126	int blkmaj;
127
128	if (major(dev) >= nchrdev || major(dev) >= nchrtoblktbl)
129		return (NODEV);
130	blkmaj = chrtoblktbl[major(dev)];
131	if (blkmaj == NODEV)
132		return (NODEV);
133	return (makedev(blkmaj, minor(dev)));
134}
135
136/*
137 * Convert a block device number to a character device number.
138 */
139dev_t
140blktochr(dev_t dev)
141{
142	int blkmaj = major(dev);
143	int i;
144
145	if (blkmaj >= nblkdev)
146		return (NODEV);
147	for (i = 0; i < nchrtoblktbl; i++)
148		if (blkmaj == chrtoblktbl[i])
149			return (makedev(i, minor(dev)));
150	return (NODEV);
151}
152
153/*
154 * Check that we're in a context where it's okay to sleep.
155 */
156void
157assertwaitok(void)
158{
159	if (panicstr || db_active)
160		return;
161
162	splassert(IPL_NONE);
163	SMR_ASSERT_NONCRITICAL();
164#ifdef DIAGNOSTIC
165	if (curcpu()->ci_mutex_level != 0)
166		panic("assertwaitok: non-zero mutex count: %d",
167		    curcpu()->ci_mutex_level);
168#endif
169}
170