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 */
48 int
enodev(void)49 enodev(void)
50 {
51
52 return (ENODEV);
53 }
54
55 /*
56 * Unconfigured device function; driver not configured.
57 */
58 int
enxio(void)59 enxio(void)
60 {
61
62 return (ENXIO);
63 }
64
65 /*
66 * Unsupported ioctl function.
67 */
68 int
enoioctl(void)69 enoioctl(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 */
80 int
enosys(void)81 enosys(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 */
91 int
eopnotsupp(void * v)92 eopnotsupp(void *v)
93 {
94
95 return (EOPNOTSUPP);
96 }
97
98 /*
99 * Generic null operation, always returns success.
100 */
101 int
nullop(void * v)102 nullop(void *v)
103 {
104
105 return (0);
106 }
107
108 struct bdevsw *
bdevsw_lookup(dev_t dev)109 bdevsw_lookup(dev_t dev)
110 {
111 return (&bdevsw[major(dev)]);
112 }
113
114 struct cdevsw *
cdevsw_lookup(dev_t dev)115 cdevsw_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 */
123 dev_t
chrtoblk(dev_t dev)124 chrtoblk(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 */
139 dev_t
blktochr(dev_t dev)140 blktochr(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 */
156 void
assertwaitok(void)157 assertwaitok(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