kern_conf.c revision 142702 
1/*-
2 * Copyright (c) 1999-2002 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/kern/kern_conf.c 142702 2005-02-27 21:52:42Z phk $");
29
30#include <sys/param.h>
31#include <sys/kernel.h>
32#include <sys/systm.h>
33#include <sys/bio.h>
34#include <sys/lock.h>
35#include <sys/mutex.h>
36#include <sys/sysctl.h>
37#include <sys/module.h>
38#include <sys/malloc.h>
39#include <sys/conf.h>
40#include <sys/vnode.h>
41#include <sys/queue.h>
42#include <sys/poll.h>
43#include <sys/ctype.h>
44#include <sys/tty.h>
45#include <machine/stdarg.h>
46
47static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
48
49/* Built at compile time from sys/conf/majors */
50extern unsigned char reserved_majors[256];
51
52/*
53 * This is the number of hash-buckets.  Experiments with 'real-life'
54 * dev_t's show that a prime halfway between two powers of two works
55 * best.
56 */
57#define DEVT_HASH 83
58
59static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
60
61static struct mtx devmtx;
62static void freedev(struct cdev *dev);
63static struct cdev *newdev(int x, int y, struct cdev *);
64static void destroy_devl(struct cdev *dev);
65
66void
67dev_lock(void)
68{
69	if (!mtx_initialized(&devmtx))
70		mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
71	mtx_lock(&devmtx);
72}
73
74void
75dev_unlock(void)
76{
77
78	mtx_unlock(&devmtx);
79}
80
81void
82dev_ref(struct cdev *dev)
83{
84
85	mtx_assert(&devmtx, MA_OWNED);
86	dev->si_refcount++;
87}
88
89void
90dev_rel(struct cdev *dev)
91{
92	int flag = 0;
93
94	mtx_assert(&devmtx, MA_NOTOWNED);
95	dev_lock();
96	dev->si_refcount--;
97	KASSERT(dev->si_refcount >= 0,
98	    ("dev_rel(%s) gave negative count", devtoname(dev)));
99	if (dev->si_usecount == 0 &&
100	    (dev->si_flags & SI_CHEAPCLONE) && (dev->si_flags & SI_NAMED))
101	if (dev->si_devsw == NULL && dev->si_refcount == 0) {
102		LIST_REMOVE(dev, si_list);
103		flag = 1;
104	}
105	dev_unlock();
106	if (flag)
107		freedev(dev);
108}
109
110struct cdevsw *
111dev_refthread(struct cdev *dev)
112{
113	struct cdevsw *csw;
114
115	mtx_assert(&devmtx, MA_NOTOWNED);
116	dev_lock();
117	csw = dev->si_devsw;
118	if (csw != NULL)
119		dev->si_threadcount++;
120	dev_unlock();
121	return (csw);
122}
123
124void
125dev_relthread(struct cdev *dev)
126{
127
128	mtx_assert(&devmtx, MA_NOTOWNED);
129	dev_lock();
130	dev->si_threadcount--;
131	dev_unlock();
132}
133
134int
135nullop(void)
136{
137
138	return (0);
139}
140
141int
142eopnotsupp(void)
143{
144
145	return (EOPNOTSUPP);
146}
147
148static int
149enxio(void)
150{
151	return (ENXIO);
152}
153
154static int
155enodev(void)
156{
157	return (ENODEV);
158}
159
160/* Define a dead_cdevsw for use when devices leave unexpectedly. */
161
162#define dead_open	(d_open_t *)enxio
163#define dead_close	(d_close_t *)enxio
164#define dead_read	(d_read_t *)enxio
165#define dead_write	(d_write_t *)enxio
166#define dead_ioctl	(d_ioctl_t *)enxio
167#define dead_poll	(d_poll_t *)enodev
168#define dead_mmap	(d_mmap_t *)enodev
169
170static void
171dead_strategy(struct bio *bp)
172{
173
174	biofinish(bp, NULL, ENXIO);
175}
176
177#define dead_dump	(dumper_t *)enxio
178#define dead_kqfilter	(d_kqfilter_t *)enxio
179
180static struct cdevsw dead_cdevsw = {
181	.d_version =	D_VERSION,
182	.d_flags =	D_NEEDGIANT, /* XXX: does dead_strategy need this ? */
183	.d_open =	dead_open,
184	.d_close =	dead_close,
185	.d_read =	dead_read,
186	.d_write =	dead_write,
187	.d_ioctl =	dead_ioctl,
188	.d_poll =	dead_poll,
189	.d_mmap =	dead_mmap,
190	.d_strategy =	dead_strategy,
191	.d_name =	"dead",
192	.d_maj =	255,
193	.d_dump =	dead_dump,
194	.d_kqfilter =	dead_kqfilter
195};
196
197/* Default methods if driver does not specify method */
198
199#define null_open	(d_open_t *)nullop
200#define null_close	(d_close_t *)nullop
201#define no_read		(d_read_t *)enodev
202#define no_write	(d_write_t *)enodev
203#define no_ioctl	(d_ioctl_t *)enodev
204#define no_mmap		(d_mmap_t *)enodev
205#define no_kqfilter	(d_kqfilter_t *)enodev
206
207static void
208no_strategy(struct bio *bp)
209{
210
211	biofinish(bp, NULL, ENODEV);
212}
213
214static int
215no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
216{
217	/*
218	 * Return true for read/write.  If the user asked for something
219	 * special, return POLLNVAL, so that clients have a way of
220	 * determining reliably whether or not the extended
221	 * functionality is present without hard-coding knowledge
222	 * of specific filesystem implementations.
223	 * Stay in sync with vop_nopoll().
224	 */
225	if (events & ~POLLSTANDARD)
226		return (POLLNVAL);
227
228	return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
229}
230
231#define no_dump		(dumper_t *)enodev
232
233/*
234 * struct cdev * and u_dev_t primitives
235 */
236
237int
238major(struct cdev *x)
239{
240	if (x == NULL)
241		return NODEV;
242	return((x->si_udev >> 8) & 0xff);
243}
244
245int
246minor(struct cdev *x)
247{
248	if (x == NULL)
249		return NODEV;
250	return(x->si_udev & MAXMINOR);
251}
252
253int
254dev2unit(struct cdev *x)
255{
256
257	if (x == NULL)
258		return NODEV;
259	return (minor2unit(minor(x)));
260}
261
262int
263minor2unit(int _minor)
264{
265
266	KASSERT((_minor & ~MAXMINOR) == 0, ("Illegal minor %x", _minor));
267	return ((_minor & 0xff) | (_minor >> 8));
268}
269
270int
271unit2minor(int unit)
272{
273
274	KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
275	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
276}
277
278static struct cdev *
279allocdev(void)
280{
281	struct cdev *si;
282
283	si = malloc(sizeof *si, M_DEVT, M_USE_RESERVE | M_ZERO | M_WAITOK);
284	si->si_name = si->__si_namebuf;
285	LIST_INIT(&si->si_children);
286	LIST_INIT(&si->si_alist);
287	return (si);
288}
289
290static struct cdev *
291newdev(int x, int y, struct cdev *si)
292{
293	struct cdev *si2;
294	dev_t	udev;
295	int hash;
296
297	mtx_assert(&devmtx, MA_OWNED);
298	if (x == umajor(NODEV) && y == uminor(NODEV))
299		panic("newdev of NODEV");
300	udev = (x << 8) | y;
301	hash = udev % DEVT_HASH;
302	LIST_FOREACH(si2, &dev_hash[hash], si_hash) {
303		if (si2->si_udev == udev) {
304			freedev(si);
305			return (si2);
306		}
307	}
308	si->si_udev = udev;
309	LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
310	return (si);
311}
312
313static void
314freedev(struct cdev *dev)
315{
316
317	free(dev, M_DEVT);
318}
319
320dev_t
321dev2udev(struct cdev *x)
322{
323	if (x == NULL)
324		return (NODEV);
325	return (x->si_udev);
326}
327
328struct cdev *
329findcdev(dev_t udev)
330{
331	struct cdev *si;
332	int hash;
333
334	mtx_assert(&devmtx, MA_NOTOWNED);
335	if (udev == NODEV)
336		return (NULL);
337	dev_lock();
338	hash = udev % DEVT_HASH;
339	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
340		if (si->si_udev == udev)
341			break;
342	}
343	dev_unlock();
344	return (si);
345}
346
347int
348uminor(dev_t dev)
349{
350	return (dev & MAXMINOR);
351}
352
353int
354umajor(dev_t dev)
355{
356	return ((dev & ~MAXMINOR) >> 8);
357}
358
359static void
360find_major(struct cdevsw *devsw)
361{
362	int i;
363
364	for (i = NUMCDEVSW - 1; i > 0; i--)
365		if (reserved_majors[i] != i)
366			break;
367	KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name));
368	devsw->d_maj = i;
369	reserved_majors[i] = i;
370	devsw->d_flags |= D_ALLOCMAJ;
371}
372
373static void
374fini_cdevsw(struct cdevsw *devsw)
375{
376	if (devsw->d_flags & D_ALLOCMAJ) {
377		reserved_majors[devsw->d_maj] = 0;
378		devsw->d_maj = MAJOR_AUTO;
379		devsw->d_flags &= ~D_ALLOCMAJ;
380	}
381	devsw->d_flags &= ~D_INIT;
382}
383
384static void
385prep_cdevsw(struct cdevsw *devsw)
386{
387
388	dev_lock();
389
390	if (devsw->d_version != D_VERSION_00) {
391		printf(
392		    "WARNING: Device driver \"%s\" has wrong version %s\n",
393		    devsw->d_name, "and is disabled.  Recompile KLD module.");
394		devsw->d_open = dead_open;
395		devsw->d_close = dead_close;
396		devsw->d_read = dead_read;
397		devsw->d_write = dead_write;
398		devsw->d_ioctl = dead_ioctl;
399		devsw->d_poll = dead_poll;
400		devsw->d_mmap = dead_mmap;
401		devsw->d_strategy = dead_strategy;
402		devsw->d_dump = dead_dump;
403		devsw->d_kqfilter = dead_kqfilter;
404	}
405
406	if (devsw->d_flags & D_TTY) {
407		if (devsw->d_ioctl == NULL)	devsw->d_ioctl = ttyioctl;
408		if (devsw->d_read == NULL)	devsw->d_read = ttyread;
409		if (devsw->d_write == NULL)	devsw->d_write = ttywrite;
410		if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = ttykqfilter;
411		if (devsw->d_poll == NULL)	devsw->d_poll = ttypoll;
412	}
413
414	if (devsw->d_open == NULL)	devsw->d_open = null_open;
415	if (devsw->d_close == NULL)	devsw->d_close = null_close;
416	if (devsw->d_read == NULL)	devsw->d_read = no_read;
417	if (devsw->d_write == NULL)	devsw->d_write = no_write;
418	if (devsw->d_ioctl == NULL)	devsw->d_ioctl = no_ioctl;
419	if (devsw->d_poll == NULL)	devsw->d_poll = no_poll;
420	if (devsw->d_mmap == NULL)	devsw->d_mmap = no_mmap;
421	if (devsw->d_strategy == NULL)	devsw->d_strategy = no_strategy;
422	if (devsw->d_dump == NULL)	devsw->d_dump = no_dump;
423	if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = no_kqfilter;
424
425	LIST_INIT(&devsw->d_devs);
426
427	devsw->d_flags |= D_INIT;
428
429	if (devsw->d_maj == MAJOR_AUTO) {
430		find_major(devsw);
431	} else {
432		KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256,
433		    ("Invalid major (%d) in make_dev", devsw->d_maj));
434		if (reserved_majors[devsw->d_maj] != devsw->d_maj) {
435			printf("WARNING: driver \"%s\" used %s %d\n",
436			    devsw->d_name, "unreserved major device number",
437			    devsw->d_maj);
438			reserved_majors[devsw->d_maj] = devsw->d_maj;
439		}
440	}
441	dev_unlock();
442}
443
444struct cdev *
445make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
446{
447	struct cdev *dev;
448	va_list ap;
449	int i;
450
451	KASSERT((minornr & ~MAXMINOR) == 0,
452	    ("Invalid minor (0x%x) in make_dev", minornr));
453
454	if (!(devsw->d_flags & D_INIT))
455		prep_cdevsw(devsw);
456	dev = allocdev();
457	dev_lock();
458	dev = newdev(devsw->d_maj, minornr, dev);
459	if (dev->si_flags & SI_CHEAPCLONE &&
460	    dev->si_flags & SI_NAMED &&
461	    dev->si_devsw == devsw) {
462		/*
463		 * This is allowed as it removes races and generally
464		 * simplifies cloning devices.
465		 * XXX: still ??
466		 */
467		dev_unlock();
468		return (dev);
469	}
470	KASSERT(!(dev->si_flags & SI_NAMED),
471	    ("make_dev() by driver %s on pre-existing device (maj=%d, min=%d, name=%s)",
472	    devsw->d_name, major(dev), minor(dev), devtoname(dev)));
473
474	va_start(ap, fmt);
475	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
476	if (i > (sizeof dev->__si_namebuf - 1)) {
477		printf("WARNING: Device name truncated! (%s)\n",
478		    dev->__si_namebuf);
479	}
480	va_end(ap);
481
482	dev->si_devsw = devsw;
483	dev->si_uid = uid;
484	dev->si_gid = gid;
485	dev->si_mode = perms;
486	dev->si_flags |= SI_NAMED;
487
488	LIST_INSERT_HEAD(&devsw->d_devs, dev, si_list);
489	devfs_create(dev);
490	dev_unlock();
491	return (dev);
492}
493
494int
495dev_named(struct cdev *pdev, const char *name)
496{
497	struct cdev *cdev;
498
499	if (strcmp(devtoname(pdev), name) == 0)
500		return (1);
501	LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
502		if (strcmp(devtoname(cdev), name) == 0)
503			return (1);
504	return (0);
505}
506
507void
508dev_depends(struct cdev *pdev, struct cdev *cdev)
509{
510
511	dev_lock();
512	cdev->si_parent = pdev;
513	cdev->si_flags |= SI_CHILD;
514	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
515	dev_unlock();
516}
517
518struct cdev *
519make_dev_alias(struct cdev *pdev, const char *fmt, ...)
520{
521	struct cdev *dev;
522	va_list ap;
523	int i;
524
525	dev = allocdev();
526	dev_lock();
527	dev->si_flags |= SI_ALIAS;
528	dev->si_flags |= SI_NAMED;
529	va_start(ap, fmt);
530	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
531	if (i > (sizeof dev->__si_namebuf - 1)) {
532		printf("WARNING: Device name truncated! (%s)\n",
533		    dev->__si_namebuf);
534	}
535	va_end(ap);
536
537	devfs_create(dev);
538	dev_unlock();
539	dev_depends(pdev, dev);
540	return (dev);
541}
542
543static void
544destroy_devl(struct cdev *dev)
545{
546	struct cdevsw *csw;
547
548	mtx_assert(&devmtx, MA_OWNED);
549	KASSERT(dev->si_flags & SI_NAMED,
550	    ("WARNING: Driver mistake: destroy_dev on %d/%d\n",
551	    major(dev), minor(dev)));
552
553	devfs_destroy(dev);
554
555	/* Remove name marking */
556	dev->si_flags &= ~SI_NAMED;
557
558	/* If we are a child, remove us from the parents list */
559	if (dev->si_flags & SI_CHILD) {
560		LIST_REMOVE(dev, si_siblings);
561		dev->si_flags &= ~SI_CHILD;
562	}
563
564	/* Kill our children */
565	while (!LIST_EMPTY(&dev->si_children))
566		destroy_devl(LIST_FIRST(&dev->si_children));
567
568	/* Remove from clone list */
569	if (dev->si_flags & SI_CLONELIST) {
570		LIST_REMOVE(dev, si_clone);
571		dev->si_flags &= ~SI_CLONELIST;
572	}
573
574	csw = dev->si_devsw;
575	dev->si_devsw = NULL;	/* already NULL for SI_ALIAS */
576	while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
577		printf("Purging %lu threads from %s\n",
578		    dev->si_threadcount, devtoname(dev));
579		csw->d_purge(dev);
580		msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
581	}
582	if (csw != NULL && csw->d_purge != NULL)
583		printf("All threads purged from %s\n", devtoname(dev));
584
585	dev->si_drv1 = 0;
586	dev->si_drv2 = 0;
587	bzero(&dev->__si_u, sizeof(dev->__si_u));
588
589	if (!(dev->si_flags & SI_ALIAS)) {
590		/* Remove from cdevsw list */
591		LIST_REMOVE(dev, si_list);
592
593		/* If cdevsw has no struct cdev *'s, clean it */
594		if (LIST_EMPTY(&csw->d_devs))
595			fini_cdevsw(csw);
596
597		LIST_REMOVE(dev, si_hash);
598	}
599	dev->si_flags &= ~SI_ALIAS;
600
601	if (dev->si_refcount > 0) {
602		LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
603	} else {
604		freedev(dev);
605	}
606}
607
608void
609destroy_dev(struct cdev *dev)
610{
611
612	dev_lock();
613	destroy_devl(dev);
614	dev_unlock();
615}
616
617const char *
618devtoname(struct cdev *dev)
619{
620	char *p;
621	struct cdevsw *csw;
622	int mynor;
623
624	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
625		p = dev->si_name;
626		sprintf(p, "#%d", major(dev));
627		p += strlen(p);
628		csw = dev_refthread(dev);
629		if (csw != NULL) {
630			sprintf(p, "(%s)", csw->d_name);
631			dev_relthread(dev);
632		}
633		p += strlen(p);
634		mynor = minor(dev);
635		if (mynor < 0 || mynor > 255)
636			sprintf(p, "/%#x", (u_int)mynor);
637		else
638			sprintf(p, "/%d", mynor);
639	}
640	return (dev->si_name);
641}
642
643int
644dev_stdclone(char *name, char **namep, const char *stem, int *unit)
645{
646	int u, i;
647
648	i = strlen(stem);
649	if (bcmp(stem, name, i) != 0)
650		return (0);
651	if (!isdigit(name[i]))
652		return (0);
653	u = 0;
654	if (name[i] == '0' && isdigit(name[i+1]))
655		return (0);
656	while (isdigit(name[i])) {
657		u *= 10;
658		u += name[i++] - '0';
659	}
660	if (u > 0xffffff)
661		return (0);
662	*unit = u;
663	if (namep)
664		*namep = &name[i];
665	if (name[i])
666		return (2);
667	return (1);
668}
669
670/*
671 * Helper functions for cloning device drivers.
672 *
673 * The objective here is to make it unnecessary for the device drivers to
674 * use rman or similar to manage their unit number space.  Due to the way
675 * we do "on-demand" devices, using rman or other "private" methods
676 * will be very tricky to lock down properly once we lock down this file.
677 *
678 * Instead we give the drivers these routines which puts the struct cdev *'s
679 * that are to be managed on their own list, and gives the driver the ability
680 * to ask for the first free unit number or a given specified unit number.
681 *
682 * In addition these routines support paired devices (pty, nmdm and similar)
683 * by respecting a number of "flag" bits in the minor number.
684 *
685 */
686
687struct clonedevs {
688	LIST_HEAD(,cdev)	head;
689};
690
691void
692clone_setup(struct clonedevs **cdp)
693{
694
695	*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
696	LIST_INIT(&(*cdp)->head);
697}
698
699int
700clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra)
701{
702	struct clonedevs *cd;
703	struct cdev *dev, *ndev, *dl, *de;
704	int unit, low, u;
705
706	KASSERT(*cdp != NULL,
707	    ("clone_setup() not called in driver \"%s\"", csw->d_name));
708	KASSERT(!(extra & CLONE_UNITMASK),
709	    ("Illegal extra bits (0x%x) in clone_create", extra));
710	KASSERT(*up <= CLONE_UNITMASK,
711	    ("Too high unit (0x%x) in clone_create", *up));
712
713	if (csw->d_maj == MAJOR_AUTO)
714		find_major(csw);
715
716	/*
717	 * Search the list for a lot of things in one go:
718	 *   A preexisting match is returned immediately.
719	 *   The lowest free unit number if we are passed -1, and the place
720	 *	 in the list where we should insert that new element.
721	 *   The place to insert a specified unit number, if applicable
722	 *       the end of the list.
723	 */
724	unit = *up;
725	ndev = allocdev();
726	dev_lock();
727	low = extra;
728	de = dl = NULL;
729	cd = *cdp;
730	LIST_FOREACH(dev, &cd->head, si_clone) {
731		KASSERT(dev->si_flags & SI_CLONELIST,
732		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
733		u = dev2unit(dev);
734		if (u == (unit | extra)) {
735			*dp = dev;
736			freedev(ndev);
737			dev_unlock();
738			return (0);
739		}
740		if (unit == -1 && u == low) {
741			low++;
742			de = dev;
743			continue;
744		}
745		if (u > (unit | extra)) {
746			dl = dev;
747			break;
748		}
749	}
750	if (unit == -1)
751		unit = low & CLONE_UNITMASK;
752	dev = newdev(csw->d_maj, unit2minor(unit | extra), ndev);
753	if (dev->si_flags & SI_CLONELIST) {
754		printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
755		printf("unit=%d\n", unit);
756		LIST_FOREACH(dev, &cd->head, si_clone) {
757			printf("\t%p %s\n", dev, dev->si_name);
758		}
759		panic("foo");
760	}
761	KASSERT(!(dev->si_flags & SI_CLONELIST),
762	    ("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
763	if (dl != NULL)
764		LIST_INSERT_BEFORE(dl, dev, si_clone);
765	else if (de != NULL)
766		LIST_INSERT_AFTER(de, dev, si_clone);
767	else
768		LIST_INSERT_HEAD(&cd->head, dev, si_clone);
769	dev->si_flags |= SI_CLONELIST;
770	*up = unit;
771	dev_unlock();
772	return (1);
773}
774
775/*
776 * Kill everything still on the list.  The driver should already have
777 * disposed of any softc hung of the struct cdev *'s at this time.
778 */
779void
780clone_cleanup(struct clonedevs **cdp)
781{
782	struct cdev *dev, *tdev;
783	struct clonedevs *cd;
784
785	cd = *cdp;
786	if (cd == NULL)
787		return;
788	dev_lock();
789	LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) {
790		KASSERT(dev->si_flags & SI_CLONELIST,
791		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
792		KASSERT(dev->si_flags & SI_NAMED,
793		    ("Driver has goofed in cloning underways udev %x", dev->si_udev));
794		destroy_devl(dev);
795	}
796	dev_unlock();
797	free(cd, M_DEVBUF);
798	*cdp = NULL;
799}
800
801/*
802 * Helper sysctl for devname(3).  We're given a struct cdev * and return
803 * the name, if any, registered by the device driver.
804 */
805static int
806sysctl_devname(SYSCTL_HANDLER_ARGS)
807{
808	int error;
809	dev_t ud;
810	struct cdev *dev;
811
812	error = SYSCTL_IN(req, &ud, sizeof (ud));
813	if (error)
814		return (error);
815	if (ud == NODEV)
816		return(EINVAL);
817	dev = findcdev(ud);
818	if (dev == NULL)
819		error = ENOENT;
820	else
821		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
822	return (error);
823}
824
825SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
826	NULL, 0, sysctl_devname, "", "devname(3) handler");
827