kern_conf.c revision 140963 
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 140963 2005-01-29 15:07:13Z 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 *);
64
65void
66dev_lock(void)
67{
68	if (!mtx_initialized(&devmtx))
69		mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
70	mtx_lock(&devmtx);
71}
72
73void
74dev_unlock(void)
75{
76
77	mtx_unlock(&devmtx);
78}
79
80void
81dev_ref(struct cdev *dev)
82{
83
84	dev_lock();
85	dev->si_refcount++;
86	dev_unlock();
87}
88
89void
90dev_rel(struct vnode *vp)
91{
92	struct cdev *dev;
93	int flag;
94
95	dev = vp->v_rdev;
96	mtx_assert(&devmtx, MA_NOTOWNED);
97	dev_lock();
98	SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_specnext);
99	dev->si_usecount -= vp->v_usecount;
100	vp->v_rdev = NULL;
101	dev->si_refcount--;
102	KASSERT(dev->si_refcount >= 0,
103	    ("dev_rel(%s) gave negative count", devtoname(dev)));
104	flag = 0;
105	if (dev->si_devsw == NULL && dev->si_refcount == 0) {
106		LIST_REMOVE(dev, si_list);
107		flag = 1;
108	}
109	dev_unlock();
110	if (flag)
111		freedev(dev);
112	return;
113}
114
115struct cdevsw *
116dev_refthread(struct cdev *dev)
117{
118	struct cdevsw *csw;
119
120	mtx_assert(&devmtx, MA_NOTOWNED);
121	dev_lock();
122	csw = dev->si_devsw;
123	if (csw != NULL)
124		dev->si_threadcount++;
125	dev_unlock();
126	return (csw);
127}
128
129void
130dev_relthread(struct cdev *dev)
131{
132
133	mtx_assert(&devmtx, MA_NOTOWNED);
134	dev_lock();
135	dev->si_threadcount--;
136	dev_unlock();
137}
138
139int
140nullop(void)
141{
142
143	return (0);
144}
145
146int
147eopnotsupp(void)
148{
149
150	return (EOPNOTSUPP);
151}
152
153static int
154enxio(void)
155{
156	return (ENXIO);
157}
158
159static int
160enodev(void)
161{
162	return (ENODEV);
163}
164
165/* Define a dead_cdevsw for use when devices leave unexpectedly. */
166
167#define dead_open	(d_open_t *)enxio
168#define dead_close	(d_close_t *)enxio
169#define dead_read	(d_read_t *)enxio
170#define dead_write	(d_write_t *)enxio
171#define dead_ioctl	(d_ioctl_t *)enxio
172#define dead_poll	(d_poll_t *)enodev
173#define dead_mmap	(d_mmap_t *)enodev
174
175static void
176dead_strategy(struct bio *bp)
177{
178
179	biofinish(bp, NULL, ENXIO);
180}
181
182#define dead_dump	(dumper_t *)enxio
183#define dead_kqfilter	(d_kqfilter_t *)enxio
184
185static struct cdevsw dead_cdevsw = {
186	.d_version =	D_VERSION,
187	.d_flags =	D_NEEDGIANT, /* XXX: does dead_strategy need this ? */
188	.d_open =	dead_open,
189	.d_close =	dead_close,
190	.d_read =	dead_read,
191	.d_write =	dead_write,
192	.d_ioctl =	dead_ioctl,
193	.d_poll =	dead_poll,
194	.d_mmap =	dead_mmap,
195	.d_strategy =	dead_strategy,
196	.d_name =	"dead",
197	.d_maj =	255,
198	.d_dump =	dead_dump,
199	.d_kqfilter =	dead_kqfilter
200};
201
202/* Default methods if driver does not specify method */
203
204#define null_open	(d_open_t *)nullop
205#define null_close	(d_close_t *)nullop
206#define no_read		(d_read_t *)enodev
207#define no_write	(d_write_t *)enodev
208#define no_ioctl	(d_ioctl_t *)enodev
209#define no_mmap		(d_mmap_t *)enodev
210#define no_kqfilter	(d_kqfilter_t *)enodev
211
212static void
213no_strategy(struct bio *bp)
214{
215
216	biofinish(bp, NULL, ENODEV);
217}
218
219static int
220no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
221{
222	/*
223	 * Return true for read/write.  If the user asked for something
224	 * special, return POLLNVAL, so that clients have a way of
225	 * determining reliably whether or not the extended
226	 * functionality is present without hard-coding knowledge
227	 * of specific filesystem implementations.
228	 * Stay in sync with vop_nopoll().
229	 */
230	if (events & ~POLLSTANDARD)
231		return (POLLNVAL);
232
233	return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
234}
235
236#define no_dump		(dumper_t *)enodev
237
238/*
239 * struct cdev * and u_dev_t primitives
240 */
241
242int
243major(struct cdev *x)
244{
245	if (x == NULL)
246		return NODEV;
247	return((x->si_udev >> 8) & 0xff);
248}
249
250int
251minor(struct cdev *x)
252{
253	if (x == NULL)
254		return NODEV;
255	return(x->si_udev & 0xffff00ff);
256}
257
258int
259dev2unit(struct cdev *x)
260{
261
262	if (x == NULL)
263		return NODEV;
264	return (minor2unit(minor(x));
265}
266
267int
268minor2unit(int _minor)
269{
270
271	KASSERT((_minor & 0xff00) == 0, ("Illegal minor %x", _minor));
272	return ((_minor & 0xff) | (_minor >> 8));
273}
274
275int
276unit2minor(int unit)
277{
278
279	KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
280	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
281}
282
283static struct cdev *
284allocdev(void)
285{
286	struct cdev *si;
287
288	si = malloc(sizeof *si, M_DEVT, M_USE_RESERVE | M_ZERO | M_WAITOK);
289	si->si_name = si->__si_namebuf;
290	LIST_INIT(&si->si_children);
291	return (si);
292}
293
294static struct cdev *
295newdev(int x, int y, struct cdev *si)
296{
297	struct cdev *si2;
298	dev_t	udev;
299	int hash;
300
301	mtx_assert(&devmtx, MA_OWNED);
302	if (x == umajor(NODEV) && y == uminor(NODEV))
303		panic("newdev of NODEV");
304	udev = (x << 8) | y;
305	hash = udev % DEVT_HASH;
306	LIST_FOREACH(si2, &dev_hash[hash], si_hash) {
307		if (si2->si_udev == udev) {
308			freedev(si);
309			return (si2);
310		}
311	}
312	si->si_udev = udev;
313	LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
314	return (si);
315}
316
317static void
318freedev(struct cdev *dev)
319{
320
321	free(dev, M_DEVT);
322}
323
324dev_t
325dev2udev(struct cdev *x)
326{
327	if (x == NULL)
328		return (NODEV);
329	return (x->si_udev);
330}
331
332struct cdev *
333findcdev(dev_t udev)
334{
335	struct cdev *si;
336	int hash;
337
338	mtx_assert(&devmtx, MA_NOTOWNED);
339	if (udev == NODEV)
340		return (NULL);
341	dev_lock();
342	hash = udev % DEVT_HASH;
343	LIST_FOREACH(si, &dev_hash[hash], si_hash) {
344		if (si->si_udev == udev)
345			break;
346	}
347	dev_unlock();
348	return (si);
349}
350
351int
352uminor(dev_t dev)
353{
354	return (dev & 0xffff00ff);
355}
356
357int
358umajor(dev_t dev)
359{
360	return ((dev & 0xff00) >> 8);
361}
362
363static void
364find_major(struct cdevsw *devsw)
365{
366	int i;
367
368	for (i = NUMCDEVSW - 1; i > 0; i--)
369		if (reserved_majors[i] != i)
370			break;
371	KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name));
372	devsw->d_maj = i;
373	reserved_majors[i] = i;
374	devsw->d_flags |= D_ALLOCMAJ;
375}
376
377static void
378fini_cdevsw(struct cdevsw *devsw)
379{
380	if (devsw->d_flags & D_ALLOCMAJ) {
381		reserved_majors[devsw->d_maj] = 0;
382		devsw->d_maj = MAJOR_AUTO;
383		devsw->d_flags &= ~D_ALLOCMAJ;
384	} else if (devsw->d_maj == 0)
385		devsw->d_maj = 256;
386	devsw->d_flags &= ~D_INIT;
387}
388
389static void
390prep_cdevsw(struct cdevsw *devsw)
391{
392
393	dev_lock();
394
395	if (devsw->d_version != D_VERSION_00) {
396		printf(
397		    "WARNING: Device driver \"%s\" has wrong version %s\n",
398		    devsw->d_name, "and is disabled.  Recompile KLD module.");
399		devsw->d_open = dead_open;
400		devsw->d_close = dead_close;
401		devsw->d_read = dead_read;
402		devsw->d_write = dead_write;
403		devsw->d_ioctl = dead_ioctl;
404		devsw->d_poll = dead_poll;
405		devsw->d_mmap = dead_mmap;
406		devsw->d_strategy = dead_strategy;
407		devsw->d_dump = dead_dump;
408		devsw->d_kqfilter = dead_kqfilter;
409	}
410
411	if (devsw->d_flags & D_TTY) {
412		if (devsw->d_ioctl == NULL)	devsw->d_ioctl = ttyioctl;
413		if (devsw->d_read == NULL)	devsw->d_read = ttyread;
414		if (devsw->d_write == NULL)	devsw->d_write = ttywrite;
415		if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = ttykqfilter;
416		if (devsw->d_poll == NULL)	devsw->d_poll = ttypoll;
417	}
418
419	if (devsw->d_open == NULL)	devsw->d_open = null_open;
420	if (devsw->d_close == NULL)	devsw->d_close = null_close;
421	if (devsw->d_read == NULL)	devsw->d_read = no_read;
422	if (devsw->d_write == NULL)	devsw->d_write = no_write;
423	if (devsw->d_ioctl == NULL)	devsw->d_ioctl = no_ioctl;
424	if (devsw->d_poll == NULL)	devsw->d_poll = no_poll;
425	if (devsw->d_mmap == NULL)	devsw->d_mmap = no_mmap;
426	if (devsw->d_strategy == NULL)	devsw->d_strategy = no_strategy;
427	if (devsw->d_dump == NULL)	devsw->d_dump = no_dump;
428	if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = no_kqfilter;
429
430	LIST_INIT(&devsw->d_devs);
431
432	devsw->d_flags |= D_INIT;
433
434	if (devsw->d_maj == MAJOR_AUTO) {
435		find_major(devsw);
436	} else {
437		if (devsw->d_maj == 256)	/* XXX: tty_cons.c is magic */
438			devsw->d_maj = 0;
439		KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256,
440		    ("Invalid major (%d) in make_dev", devsw->d_maj));
441		if (reserved_majors[devsw->d_maj] != devsw->d_maj) {
442			printf("WARNING: driver \"%s\" used %s %d\n",
443			    devsw->d_name, "unreserved major device number",
444			    devsw->d_maj);
445			reserved_majors[devsw->d_maj] = devsw->d_maj;
446		}
447	}
448	dev_unlock();
449}
450
451struct cdev *
452make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
453{
454	struct cdev *dev;
455	va_list ap;
456	int i;
457
458	KASSERT((minornr & ~0xffff00ff) == 0,
459	    ("Invalid minor (0x%x) in make_dev", minornr));
460
461	if (!(devsw->d_flags & D_INIT))
462		prep_cdevsw(devsw);
463	dev = allocdev();
464	dev_lock();
465	dev = newdev(devsw->d_maj, minornr, dev);
466	if (dev->si_flags & SI_CHEAPCLONE &&
467	    dev->si_flags & SI_NAMED &&
468	    dev->si_devsw == devsw) {
469		/*
470		 * This is allowed as it removes races and generally
471		 * simplifies cloning devices.
472		 * XXX: still ??
473		 */
474		dev_unlock();
475		return (dev);
476	}
477	KASSERT(!(dev->si_flags & SI_NAMED),
478	    ("make_dev() by driver %s on pre-existing device (maj=%d, min=%d, name=%s)",
479	    devsw->d_name, major(dev), minor(dev), devtoname(dev)));
480
481	va_start(ap, fmt);
482	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
483	if (i > (sizeof dev->__si_namebuf - 1)) {
484		printf("WARNING: Device name truncated! (%s)\n",
485		    dev->__si_namebuf);
486	}
487	va_end(ap);
488
489	dev->si_devsw = devsw;
490	dev->si_uid = uid;
491	dev->si_gid = gid;
492	dev->si_mode = perms;
493	dev->si_flags |= SI_NAMED;
494
495	LIST_INSERT_HEAD(&devsw->d_devs, dev, si_list);
496	devfs_create(dev);
497	dev_unlock();
498	return (dev);
499}
500
501int
502dev_named(struct cdev *pdev, const char *name)
503{
504	struct cdev *cdev;
505
506	if (strcmp(devtoname(pdev), name) == 0)
507		return (1);
508	LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
509		if (strcmp(devtoname(cdev), name) == 0)
510			return (1);
511	return (0);
512}
513
514void
515dev_depends(struct cdev *pdev, struct cdev *cdev)
516{
517
518	dev_lock();
519	cdev->si_parent = pdev;
520	cdev->si_flags |= SI_CHILD;
521	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
522	dev_unlock();
523}
524
525struct cdev *
526make_dev_alias(struct cdev *pdev, const char *fmt, ...)
527{
528	struct cdev *dev;
529	va_list ap;
530	int i;
531
532	dev = allocdev();
533	dev_lock();
534	dev->si_flags |= SI_ALIAS;
535	dev->si_flags |= SI_NAMED;
536	va_start(ap, fmt);
537	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
538	if (i > (sizeof dev->__si_namebuf - 1)) {
539		printf("WARNING: Device name truncated! (%s)\n",
540		    dev->__si_namebuf);
541	}
542	va_end(ap);
543
544	devfs_create(dev);
545	dev_unlock();
546	dev_depends(pdev, dev);
547	return (dev);
548}
549
550static void
551idestroy_dev(struct cdev *dev)
552{
553	struct cdevsw *csw;
554
555	KASSERT(dev->si_flags & SI_NAMED,
556	    ("WARNING: Driver mistake: destroy_dev on %d/%d\n",
557	    major(dev), minor(dev)));
558
559	devfs_destroy(dev);
560
561	/* Remove name marking */
562	dev->si_flags &= ~SI_NAMED;
563
564	/* If we are a child, remove us from the parents list */
565	if (dev->si_flags & SI_CHILD) {
566		LIST_REMOVE(dev, si_siblings);
567		dev->si_flags &= ~SI_CHILD;
568	}
569
570	/* Kill our children */
571	while (!LIST_EMPTY(&dev->si_children))
572		idestroy_dev(LIST_FIRST(&dev->si_children));
573
574	/* Remove from clone list */
575	if (dev->si_flags & SI_CLONELIST) {
576		LIST_REMOVE(dev, si_clone);
577		dev->si_flags &= ~SI_CLONELIST;
578	}
579
580	csw = dev->si_devsw;
581	dev->si_devsw = NULL;	/* already NULL for SI_ALIAS */
582	while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
583		printf("Purging %lu threads from %s\n",
584		    dev->si_threadcount, devtoname(dev));
585		csw->d_purge(dev);
586		msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
587	}
588	if (csw != NULL && csw->d_purge != NULL)
589		printf("All threads purged from %s\n", devtoname(dev));
590
591	dev->si_drv1 = 0;
592	dev->si_drv2 = 0;
593	bzero(&dev->__si_u, sizeof(dev->__si_u));
594
595	if (!(dev->si_flags & SI_ALIAS)) {
596		/* Remove from cdevsw list */
597		LIST_REMOVE(dev, si_list);
598
599		/* If cdevsw has no struct cdev *'s, clean it */
600		if (LIST_EMPTY(&csw->d_devs))
601			fini_cdevsw(csw);
602
603		LIST_REMOVE(dev, si_hash);
604	}
605	dev->si_flags &= ~SI_ALIAS;
606
607	if (dev->si_refcount > 0) {
608		LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
609	} else {
610		freedev(dev);
611	}
612}
613
614void
615destroy_dev(struct cdev *dev)
616{
617
618	dev_lock();
619	idestroy_dev(dev);
620	dev_unlock();
621}
622
623const char *
624devtoname(struct cdev *dev)
625{
626	char *p;
627	struct cdevsw *csw;
628	int mynor;
629
630	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
631		p = dev->si_name;
632		sprintf(p, "#%d", major(dev));
633		p += strlen(p);
634		csw = dev_refthread(dev);
635		if (csw != NULL) {
636			sprintf(p, "(%s)", csw->d_name);
637			dev_relthread(dev);
638		}
639		p += strlen(p);
640		mynor = minor(dev);
641		if (mynor < 0 || mynor > 255)
642			sprintf(p, "/%#x", (u_int)mynor);
643		else
644			sprintf(p, "/%d", mynor);
645	}
646	return (dev->si_name);
647}
648
649int
650dev_stdclone(char *name, char **namep, const char *stem, int *unit)
651{
652	int u, i;
653
654	i = strlen(stem);
655	if (bcmp(stem, name, i) != 0)
656		return (0);
657	if (!isdigit(name[i]))
658		return (0);
659	u = 0;
660	if (name[i] == '0' && isdigit(name[i+1]))
661		return (0);
662	while (isdigit(name[i])) {
663		u *= 10;
664		u += name[i++] - '0';
665	}
666	if (u > 0xffffff)
667		return (0);
668	*unit = u;
669	if (namep)
670		*namep = &name[i];
671	if (name[i])
672		return (2);
673	return (1);
674}
675
676/*
677 * Helper functions for cloning device drivers.
678 *
679 * The objective here is to make it unnecessary for the device drivers to
680 * use rman or similar to manage their unit number space.  Due to the way
681 * we do "on-demand" devices, using rman or other "private" methods
682 * will be very tricky to lock down properly once we lock down this file.
683 *
684 * Instead we give the drivers these routines which puts the struct cdev *'s
685 * that are to be managed on their own list, and gives the driver the ability
686 * to ask for the first free unit number or a given specified unit number.
687 *
688 * In addition these routines support paired devices (pty, nmdm and similar)
689 * by respecting a number of "flag" bits in the minor number.
690 *
691 */
692
693struct clonedevs {
694	LIST_HEAD(,cdev)	head;
695};
696
697void
698clone_setup(struct clonedevs **cdp)
699{
700
701	*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
702	LIST_INIT(&(*cdp)->head);
703}
704
705int
706clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra)
707{
708	struct clonedevs *cd;
709	struct cdev *dev, *ndev, *dl, *de;
710	int unit, low, u;
711
712	KASSERT(*cdp != NULL,
713	    ("clone_setup() not called in driver \"%s\"", csw->d_name));
714	KASSERT(!(extra & CLONE_UNITMASK),
715	    ("Illegal extra bits (0x%x) in clone_create", extra));
716	KASSERT(*up <= CLONE_UNITMASK,
717	    ("Too high unit (0x%x) in clone_create", *up));
718
719	if (csw->d_maj == MAJOR_AUTO)
720		find_major(csw);
721
722	/*
723	 * Search the list for a lot of things in one go:
724	 *   A preexisting match is returned immediately.
725	 *   The lowest free unit number if we are passed -1, and the place
726	 *	 in the list where we should insert that new element.
727	 *   The place to insert a specified unit number, if applicable
728	 *       the end of the list.
729	 */
730	unit = *up;
731	ndev = allocdev();
732	dev_lock();
733	low = extra;
734	de = dl = NULL;
735	cd = *cdp;
736	LIST_FOREACH(dev, &cd->head, si_clone) {
737		KASSERT(dev->si_flags & SI_CLONELIST,
738		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
739		u = dev2unit(dev);
740		if (u == (unit | extra)) {
741			*dp = dev;
742			freedev(ndev);
743			dev_unlock();
744			return (0);
745		}
746		if (unit == -1 && u == low) {
747			low++;
748			de = dev;
749			continue;
750		}
751		if (u > (unit | extra)) {
752			dl = dev;
753			break;
754		}
755	}
756	if (unit == -1)
757		unit = low & CLONE_UNITMASK;
758	dev = newdev(csw->d_maj, unit2minor(unit | extra), ndev);
759	if (dev->si_flags & SI_CLONELIST) {
760		printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
761		printf("unit=%d\n", unit);
762		LIST_FOREACH(dev, &cd->head, si_clone) {
763			printf("\t%p %s\n", dev, dev->si_name);
764		}
765		panic("foo");
766	}
767	KASSERT(!(dev->si_flags & SI_CLONELIST),
768	    ("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
769	if (dl != NULL)
770		LIST_INSERT_BEFORE(dl, dev, si_clone);
771	else if (de != NULL)
772		LIST_INSERT_AFTER(de, dev, si_clone);
773	else
774		LIST_INSERT_HEAD(&cd->head, dev, si_clone);
775	dev->si_flags |= SI_CLONELIST;
776	*up = unit;
777	dev_unlock();
778	return (1);
779}
780
781/*
782 * Kill everything still on the list.  The driver should already have
783 * disposed of any softc hung of the struct cdev *'s at this time.
784 */
785void
786clone_cleanup(struct clonedevs **cdp)
787{
788	struct cdev *dev, *tdev;
789	struct clonedevs *cd;
790
791	cd = *cdp;
792	if (cd == NULL)
793		return;
794	dev_lock();
795	LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) {
796		KASSERT(dev->si_flags & SI_CLONELIST,
797		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
798		KASSERT(dev->si_flags & SI_NAMED,
799		    ("Driver has goofed in cloning underways udev %x", dev->si_udev));
800		idestroy_dev(dev);
801	}
802	dev_unlock();
803	free(cd, M_DEVBUF);
804	*cdp = NULL;
805}
806
807/*
808 * Helper sysctl for devname(3).  We're given a struct cdev * and return
809 * the name, if any, registered by the device driver.
810 */
811static int
812sysctl_devname(SYSCTL_HANDLER_ARGS)
813{
814	int error;
815	dev_t ud;
816	struct cdev *dev;
817
818	error = SYSCTL_IN(req, &ud, sizeof (ud));
819	if (error)
820		return (error);
821	if (ud == NODEV)
822		return(EINVAL);
823	dev = findcdev(ud);
824	if (dev == NULL)
825		error = ENOENT;
826	else
827		error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
828	return (error);
829}
830
831SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
832	NULL, 0, sysctl_devname, "", "devname(3) handler");
833