DEVFS - remove dev_ops_add(), dev_ops_get(), and get_dev()
[dragonfly.git] / sys / kern / kern_conf.c
CommitLineData
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1/*-
2 * Parts Copyright (c) 1995 Terrence R. Lambert
3 * Copyright (c) 1995 Julian R. Elischer
4 * All rights reserved.
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 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by Terrence R. Lambert.
17 * 4. The name Terrence R. Lambert may not be used to endorse or promote
18 * products derived from this software without specific prior written
19 * permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY
22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD: src/sys/kern/kern_conf.c,v 1.73.2.3 2003/03/10 02:18:25 imp Exp $
0e9b9130 34 * $DragonFly: src/sys/kern/kern_conf.c,v 1.23 2007/05/09 00:53:34 dillon Exp $
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35 */
36
37#include <sys/param.h>
38#include <sys/kernel.h>
39#include <sys/sysctl.h>
40#include <sys/systm.h>
41#include <sys/module.h>
42#include <sys/malloc.h>
43#include <sys/conf.h>
44#include <sys/vnode.h>
45#include <sys/queue.h>
335dda38 46#include <sys/device.h>
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47#include <machine/stdarg.h>
48
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49#include <sys/sysref2.h>
50
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51#include <vfs/devfs/devfs.h>
52
53
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54static void cdev_terminate(struct cdev *dev);
55
b13267a5 56MALLOC_DEFINE(M_DEVT, "cdev_t", "dev_t storage");
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57
58/*
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59 * SYSREF Integration - reference counting, allocation,
60 * sysid and syslink integration.
61 */
62static struct sysref_class cdev_sysref_class = {
63 .name = "cdev",
64 .mtype = M_DEVT,
65 .proto = SYSREF_PROTO_DEV,
66 .offset = offsetof(struct cdev, si_sysref),
67 .objsize = sizeof(struct cdev),
68 .mag_capacity = 32,
69 .flags = 0,
70 .ops = {
71 .terminate = (sysref_terminate_func_t)cdev_terminate
72 }
73};
74
75/*
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76 * This is the number of hash-buckets. Experiements with 'real-life'
77 * udev_t's show that a prime halfway between two powers of two works
78 * best.
79 */
0e9b9130 80#define DEVT_HASH 128 /* must be power of 2 */
0de08e6d 81static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
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82
83static int free_devt;
84SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
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85int dev_ref_debug = 0;
86SYSCTL_INT(_debug, OID_AUTO, dev_refs, CTLFLAG_RW, &dev_ref_debug, 0, "");
984263bc 87
984263bc 88/*
b13267a5 89 * cdev_t and u_dev_t primitives. Note that the major number is always
0e9b9130 90 * extracted from si_umajor, not from si_devsw, because si_devsw is replaced
e4c9c0c8 91 * when a device is destroyed.
984263bc 92 */
984263bc 93int
028066b1 94major(cdev_t dev)
984263bc 95{
028066b1 96 if (dev == NULL)
984263bc 97 return NOUDEV;
0e9b9130 98 return(dev->si_umajor);
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99}
100
101int
028066b1 102minor(cdev_t dev)
984263bc 103{
028066b1 104 if (dev == NULL)
984263bc 105 return NOUDEV;
0e9b9130 106 return(dev->si_uminor);
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107}
108
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109/*
110 * Compatibility function with old udev_t format to convert the
111 * non-consecutive minor space into a consecutive minor space.
112 */
984263bc 113int
028066b1 114lminor(cdev_t dev)
984263bc 115{
0e9b9130 116 int y;
984263bc 117
028066b1 118 if (dev == NULL)
984263bc 119 return NOUDEV;
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120 y = dev->si_uminor;
121 if (y & 0x0000ff00)
122 return NOUDEV;
123 return ((y & 0xff) | (y >> 8));
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124}
125
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126/*
127 * This is a bit complex because devices are always created relative to
128 * a particular cdevsw, including 'hidden' cdevsw's (such as the raw device
129 * backing a disk subsystem overlay), so we have to compare both the
130 * devsw and udev fields to locate the correct device.
131 *
132 * The device is created if it does not already exist. If SI_ADHOC is not
133 * set the device will be referenced (once) and SI_ADHOC will be set.
134 * The caller must explicitly add additional references to the device if
135 * the caller wishes to track additional references.
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136 *
137 * NOTE: The passed ops vector must normally match the device. This is
138 * because the kernel may create shadow devices that are INVISIBLE TO
139 * USERLAND. For example, the block device backing a disk is created
140 * as a shadow underneath the user-visible disklabel management device.
141 * Sometimes a device ops vector can be overridden, such as by /dev/console.
142 * In this case and this case only we allow a match when the ops vector
143 * otherwise would not match.
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144 */
145static
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146int
147__devthash(int x, int y)
148{
149 return(((x << 2) ^ y) & (DEVT_HASH - 1));
150}
151
152static
b13267a5 153cdev_t
a13d2b31 154hashdev(struct dev_ops *ops, int x, int y, int allow_intercept)
984263bc 155{
0de08e6d 156 struct cdev *si;
984263bc 157 int hash;
984263bc 158
0e9b9130 159 hash = __devthash(x, y);
984263bc 160 LIST_FOREACH(si, &dev_hash[hash], si_hash) {
0e9b9130 161 if (si->si_umajor == x && si->si_uminor == y) {
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162 if (si->si_ops == ops)
163 return (si);
164 if (allow_intercept && (si->si_flags & SI_INTERCEPTED))
165 return (si);
d4569e90 166 }
984263bc 167 }
028066b1 168 si = sysref_alloc(&cdev_sysref_class);
fef8985e 169 si->si_ops = ops;
e4c9c0c8 170 si->si_flags |= SI_HASHED | SI_ADHOC;
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171 si->si_umajor = x;
172 si->si_uminor = y;
cd29885a 173 si->si_inode = 0;
984263bc 174 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
028066b1 175 sysref_activate(&si->si_sysref);
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176
177 dev_dclone(si);
178 if (ops != &dead_dev_ops)
179 ++ops->head.refs;
e4c9c0c8 180 if (dev_ref_debug) {
6ea70f76 181 kprintf("create dev %p %s(minor=%08x) refs=%d\n",
0e9b9130 182 si, devtoname(si), y,
028066b1 183 si->si_sysref.refcnt);
984263bc 184 }
e4c9c0c8 185 return (si);
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186}
187
e4c9c0c8 188/*
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189 * Convert a device pointer to an old style device number. Return NOUDEV
190 * if the device is invalid or if the device (maj,min) cannot be converted
191 * to an old style udev_t.
e4c9c0c8 192 */
984263bc 193udev_t
028066b1 194dev2udev(cdev_t dev)
984263bc 195{
028066b1 196 if (dev == NULL)
984263bc 197 return NOUDEV;
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198
199 return (udev_t)dev->si_inode;
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200}
201
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202/*
203 * Convert a device number to a device pointer. The device is referenced
204 * ad-hoc, meaning that the caller should call reference_dev() if it wishes
205 * to keep ahold of the returned structure long term.
206 *
207 * The returned device is associated with the currently installed cdevsw
028066b1 208 * for the requested major number. NULL is returned if the major number
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209 * has not been registered.
210 */
b13267a5 211cdev_t
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212udev2dev(udev_t x, int b)
213{
e4c9c0c8 214 if (x == NOUDEV || b != 0)
028066b1 215 return(NULL);
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216
217 return devfs_find_device_by_udev(x);
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218}
219
220int
b13267a5 221dev_is_good(cdev_t dev)
e4c9c0c8 222{
028066b1 223 if (dev != NULL && dev->si_ops != &dead_dev_ops)
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224 return(1);
225 return(0);
226}
227
228/*
229 * Various user device number extraction and conversion routines
230 */
231int
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232uminor(udev_t dev)
233{
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234 if (dev == NOUDEV)
235 return(-1);
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236 return(dev & 0xffff00ff);
237}
238
239int
240umajor(udev_t dev)
241{
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242 if (dev == NOUDEV)
243 return(-1);
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244 return((dev & 0xff00) >> 8);
245}
246
247udev_t
248makeudev(int x, int y)
249{
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250 if ((x & 0xffffff00) || (y & 0x0000ff00))
251 return NOUDEV;
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252 return ((x << 8) | y);
253}
254
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255/*
256 * Create an internal or external device.
257 *
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258 * This routine creates and returns an unreferenced ad-hoc entry for the
259 * device which will remain intact until the device is destroyed. If the
260 * caller intends to store the device pointer it must call reference_dev()
261 * to retain a real reference to the device.
262 *
263 * If an entry already exists, this function will set (or override)
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264 * its cred requirements and name (XXX DEVFS interface).
265 */
b13267a5 266cdev_t
fef8985e 267make_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
e4c9c0c8 268 int perms, const char *fmt, ...)
984263bc 269{
cd29885a 270 cdev_t devfs_dev;
e2565a42 271 __va_list ap;
984263bc 272 int i;
cd29885a 273 char dev_name[PATH_MAX+1];
984263bc 274
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275 /*
276 * compile the cdevsw and install the device
277 */
fef8985e 278 compile_dev_ops(ops);
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279
280 /*
281 * Set additional fields (XXX DEVFS interface goes here)
282 */
e2565a42 283 __va_start(ap, fmt);
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284 i = kvcprintf(fmt, NULL, dev_name, 32, ap);
285 dev_name[i] = '\0';
e2565a42 286 __va_end(ap);
984263bc 287
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288/*
289 if ((devfs_dev = devfs_find_device_by_name(dev_name)) != NULL) {
290 kprintf("make_dev: Device %s already exists, returning old dev without creating new node\n", dev_name);
291 return devfs_dev;
292 }
293*/
294
295 devfs_dev = devfs_new_cdev(ops, minor);
296 memcpy(devfs_dev->si_name, dev_name, i+1);
297
298 devfs_debug(DEVFS_DEBUG_INFO, "make_dev called for %s\n", devfs_dev->si_name);
299 devfs_create_dev(devfs_dev, uid, gid, perms);
300
301 return (devfs_dev);
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302}
303
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304
305cdev_t
306make_only_devfs_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
307 int perms, const char *fmt, ...)
308{
309 cdev_t devfs_dev;
310 __va_list ap;
311 int i;
312 //char *dev_name;
313
314 /*
315 * compile the cdevsw and install the device
316 */
317 compile_dev_ops(ops);
318 devfs_dev = devfs_new_cdev(ops, minor);
319
320 /*
321 * Set additional fields (XXX DEVFS interface goes here)
322 */
323 __va_start(ap, fmt);
324 i = kvcprintf(fmt, NULL, devfs_dev->si_name, 32, ap);
325 devfs_dev->si_name[i] = '\0';
326 __va_end(ap);
327
328
329 devfs_create_dev(devfs_dev, uid, gid, perms);
330
331 return (devfs_dev);
332}
333
334
335cdev_t
336make_only_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
337 int perms, const char *fmt, ...)
338{
339 cdev_t devfs_dev;
340 __va_list ap;
341 int i;
342 //char *dev_name;
343
344 /*
345 * compile the cdevsw and install the device
346 */
347 compile_dev_ops(ops);
348 devfs_dev = devfs_new_cdev(ops, minor);
349 devfs_dev->si_perms = perms;
350 devfs_dev->si_uid = uid;
351 devfs_dev->si_gid = gid;
352
353 /*
354 * Set additional fields (XXX DEVFS interface goes here)
355 */
356 __va_start(ap, fmt);
357 i = kvcprintf(fmt, NULL, devfs_dev->si_name, 32, ap);
358 devfs_dev->si_name[i] = '\0';
359 __va_end(ap);
360
361 reference_dev(devfs_dev);
362
363 return (devfs_dev);
364}
365
366void
367destroy_only_dev(cdev_t dev)
368{
369 devfs_destroy_cdev(dev);
370}
371
372
217ff971 373/*
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374 * This function is similar to make_dev() but no cred information or name
375 * need be specified.
376 */
b13267a5 377cdev_t
fef8985e 378make_adhoc_dev(struct dev_ops *ops, int minor)
e4c9c0c8 379{
b13267a5 380 cdev_t dev;
e4c9c0c8 381
d4569e90 382 dev = hashdev(ops, ops->head.maj, minor, FALSE);
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383 return(dev);
384}
385
386/*
387 * This function is similar to make_dev() except the new device is created
388 * using an old device as a template.
389 */
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390cdev_t
391make_sub_dev(cdev_t odev, int minor)
e4c9c0c8 392{
b13267a5 393 cdev_t dev;
e4c9c0c8 394
0e9b9130 395 dev = hashdev(odev->si_ops, odev->si_umajor, minor, FALSE);
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396
397 /*
398 * Copy cred requirements and name info XXX DEVFS.
399 */
400 if (dev->si_name[0] == 0 && odev->si_name[0])
401 bcopy(odev->si_name, dev->si_name, sizeof(dev->si_name));
402 return (dev);
403}
404
405/*
406 * destroy_dev() removes the adhoc association for a device and revectors
fef8985e 407 * its ops to &dead_dev_ops.
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408 *
409 * This routine releases the reference count associated with the ADHOC
410 * entry, plus releases the reference count held by the caller. What this
411 * means is that you should not call destroy_dev(make_dev(...)), because
412 * make_dev() does not bump the reference count (beyond what it needs to
413 * create the ad-hoc association). Any procedure that intends to destroy
414 * a device must have its own reference to it first.
217ff971 415 */
984263bc 416void
b13267a5 417destroy_dev(cdev_t dev)
984263bc 418{
e4c9c0c8 419 int hash;
217ff971 420
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421 if (dev) {
422 devfs_debug(DEVFS_DEBUG_DEBUG,
423 "destroy_dev called for %s\n",
424 dev->si_name);
425 devfs_destroy_dev(dev);
e4c9c0c8 426 }
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427}
428
429/*
430 * Destroy all ad-hoc device associations associated with a domain within a
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431 * device switch. Only the minor numbers are included in the mask/match
432 * values.
433 *
fef8985e 434 * Unlike the ops functions whos link structures do not contain
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435 * any major bits, this function scans through the dev list via
436 * si_umajor/si_uminor.
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437 *
438 * The caller must not include any major bits in the match value.
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439 */
440void
fef8985e 441destroy_all_devs(struct dev_ops *ops, u_int mask, u_int match)
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442{
443 int i;
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444 cdev_t dev;
445 cdev_t ndev;
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446
447 for (i = 0; i < DEVT_HASH; ++i) {
448 ndev = LIST_FIRST(&dev_hash[i]);
449 while ((dev = ndev) != NULL) {
450 ndev = LIST_NEXT(dev, si_hash);
fef8985e 451 if (dev->si_ops == ops &&
0e9b9130 452 ((u_int)dev->si_uminor & mask) == match
e4c9c0c8 453 ) {
493f17de 454 KKASSERT(dev->si_flags & SI_ADHOC);
028066b1 455 reference_dev(dev);
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456 destroy_dev(dev);
457 }
458 }
459 }
460}
461
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462
463int
464make_dev_alias(cdev_t target, const char *fmt, ...)
465{
466 char name[PATH_MAX + 1];
467 __va_list ap;
468 int i;
469
470 __va_start(ap, fmt);
471 i = kvcprintf(fmt, NULL, name, 32, ap);
472 name[i] = '\0';
473 __va_end(ap);
474
475 devfs_make_alias(name, target);
476
477 return 0;
478}
479
480
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481/*
482 * Add a reference to a device. Callers generally add their own references
483 * when they are going to store a device node in a variable for long periods
484 * of time, to prevent a disassociation from free()ing the node.
485 *
486 * Also note that a caller that intends to call destroy_dev() must first
487 * obtain a reference on the device. The ad-hoc reference you get with
488 * make_dev() and friends is NOT sufficient to be able to call destroy_dev().
489 */
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490cdev_t
491reference_dev(cdev_t dev)
e4c9c0c8 492{
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493 //kprintf("reference_dev\n");
494
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495 if (dev != NULL) {
496 sysref_get(&dev->si_sysref);
e4c9c0c8 497 if (dev_ref_debug) {
6ea70f76 498 kprintf("reference dev %p %s(minor=%08x) refs=%d\n",
0e9b9130 499 dev, devtoname(dev), dev->si_uminor,
028066b1 500 dev->si_sysref.refcnt);
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501 }
502 }
503 return(dev);
504}
505
506/*
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507 * release a reference on a device. The device will be terminated when the
508 * last reference has been released.
e4c9c0c8 509 *
0e9b9130 510 * NOTE: we must use si_umajor to figure out the original major number,
fef8985e 511 * because si_ops could already be pointing at dead_dev_ops.
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512 */
513void
b13267a5 514release_dev(cdev_t dev)
e4c9c0c8 515{
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516 //kprintf("release_dev\n");
517
028066b1 518 if (dev == NULL)
e4c9c0c8 519 return;
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520 sysref_put(&dev->si_sysref);
521}
522
523static
524void
525cdev_terminate(struct cdev *dev)
526{
527 int messedup = 0;
528
e4c9c0c8 529 if (dev_ref_debug) {
6ea70f76 530 kprintf("release dev %p %s(minor=%08x) refs=%d\n",
0e9b9130 531 dev, devtoname(dev), dev->si_uminor,
028066b1 532 dev->si_sysref.refcnt);
e4c9c0c8 533 }
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534 if (dev->si_flags & SI_ADHOC) {
535 kprintf("Warning: illegal final release on ADHOC"
536 " device %p(%s), the device was never"
537 " destroyed!\n",
538 dev, devtoname(dev));
539 messedup = 1;
540 }
541 if (dev->si_flags & SI_HASHED) {
542 kprintf("Warning: last release on device, no call"
543 " to destroy_dev() was made! dev %p(%s)\n",
544 dev, devtoname(dev));
545 reference_dev(dev);
546 destroy_dev(dev);
547 messedup = 1;
548 }
549 if (SLIST_FIRST(&dev->si_hlist) != NULL) {
550 kprintf("Warning: last release on device, vnode"
551 " associations still exist! dev %p(%s)\n",
552 dev, devtoname(dev));
553 messedup = 1;
554 }
555 if (dev->si_ops && dev->si_ops != &dead_dev_ops) {
556 dev_ops_release(dev->si_ops);
557 dev->si_ops = NULL;
e4c9c0c8 558 }
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559 if (messedup == 0)
560 sysref_put(&dev->si_sysref);
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561}
562
563const char *
b13267a5 564devtoname(cdev_t dev)
984263bc 565{
984263bc 566 int mynor;
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567 int len;
568 char *p;
569 const char *dname;
984263bc 570
028066b1 571 if (dev == NULL)
e4c9c0c8 572 return("#nodev");
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573 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
574 p = dev->si_name;
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575 len = sizeof(dev->si_name);
576 if ((dname = dev_dname(dev)) != NULL)
f8c7a42d 577 ksnprintf(p, len, "#%s/", dname);
984263bc 578 else
f8c7a42d 579 ksnprintf(p, len, "#%d/", major(dev));
335dda38 580 len -= strlen(p);
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581 p += strlen(p);
582 mynor = minor(dev);
583 if (mynor < 0 || mynor > 255)
f8c7a42d 584 ksnprintf(p, len, "%#x", (u_int)mynor);
984263bc 585 else
f8c7a42d 586 ksnprintf(p, len, "%d", mynor);
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587 }
588 return (dev->si_name);
589}
e4c9c0c8 590