kern_conf.c revision 163328 
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 163328 2006-10-13 20:49:24Z tegge $");
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/module.h>
37#include <sys/malloc.h>
38#include <sys/conf.h>
39#include <sys/vnode.h>
40#include <sys/queue.h>
41#include <sys/poll.h>
42#include <sys/ctype.h>
43#include <sys/tty.h>
44#include <sys/ucred.h>
45#include <machine/stdarg.h>
46
47#include <fs/devfs/devfs_int.h>
48
49static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
50
51struct mtx devmtx;
52static void destroy_devl(struct cdev *dev);
53static struct cdev *make_dev_credv(struct cdevsw *devsw, int minornr,
54	    struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
55	    va_list ap);
56
57void
58dev_lock(void)
59{
60
61	mtx_lock(&devmtx);
62}
63
64void
65dev_unlock(void)
66{
67
68	mtx_unlock(&devmtx);
69}
70
71void
72dev_ref(struct cdev *dev)
73{
74
75	mtx_assert(&devmtx, MA_NOTOWNED);
76	mtx_lock(&devmtx);
77	dev->si_refcount++;
78	mtx_unlock(&devmtx);
79}
80
81void
82dev_refl(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 0
100	if (dev->si_usecount == 0 &&
101	    (dev->si_flags & SI_CHEAPCLONE) && (dev->si_flags & SI_NAMED))
102		;
103	else
104#endif
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		devfs_free(dev);
112}
113
114struct cdevsw *
115dev_refthread(struct cdev *dev)
116{
117	struct cdevsw *csw;
118
119	mtx_assert(&devmtx, MA_NOTOWNED);
120	dev_lock();
121	csw = dev->si_devsw;
122	if (csw != NULL)
123		dev->si_threadcount++;
124	dev_unlock();
125	return (csw);
126}
127
128void
129dev_relthread(struct cdev *dev)
130{
131
132	mtx_assert(&devmtx, MA_NOTOWNED);
133	dev_lock();
134	dev->si_threadcount--;
135	dev_unlock();
136}
137
138int
139nullop(void)
140{
141
142	return (0);
143}
144
145int
146eopnotsupp(void)
147{
148
149	return (EOPNOTSUPP);
150}
151
152static int
153enxio(void)
154{
155	return (ENXIO);
156}
157
158static int
159enodev(void)
160{
161	return (ENODEV);
162}
163
164/* Define a dead_cdevsw for use when devices leave unexpectedly. */
165
166#define dead_open	(d_open_t *)enxio
167#define dead_close	(d_close_t *)enxio
168#define dead_read	(d_read_t *)enxio
169#define dead_write	(d_write_t *)enxio
170#define dead_ioctl	(d_ioctl_t *)enxio
171#define dead_poll	(d_poll_t *)enodev
172#define dead_mmap	(d_mmap_t *)enodev
173
174static void
175dead_strategy(struct bio *bp)
176{
177
178	biofinish(bp, NULL, ENXIO);
179}
180
181#define dead_dump	(dumper_t *)enxio
182#define dead_kqfilter	(d_kqfilter_t *)enxio
183
184static struct cdevsw dead_cdevsw = {
185	.d_version =	D_VERSION,
186	.d_flags =	D_NEEDGIANT, /* XXX: does dead_strategy need this ? */
187	.d_open =	dead_open,
188	.d_close =	dead_close,
189	.d_read =	dead_read,
190	.d_write =	dead_write,
191	.d_ioctl =	dead_ioctl,
192	.d_poll =	dead_poll,
193	.d_mmap =	dead_mmap,
194	.d_strategy =	dead_strategy,
195	.d_name =	"dead",
196	.d_dump =	dead_dump,
197	.d_kqfilter =	dead_kqfilter
198};
199
200/* Default methods if driver does not specify method */
201
202#define null_open	(d_open_t *)nullop
203#define null_close	(d_close_t *)nullop
204#define no_read		(d_read_t *)enodev
205#define no_write	(d_write_t *)enodev
206#define no_ioctl	(d_ioctl_t *)enodev
207#define no_mmap		(d_mmap_t *)enodev
208#define no_kqfilter	(d_kqfilter_t *)enodev
209
210static void
211no_strategy(struct bio *bp)
212{
213
214	biofinish(bp, NULL, ENODEV);
215}
216
217static int
218no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
219{
220	/*
221	 * Return true for read/write.  If the user asked for something
222	 * special, return POLLNVAL, so that clients have a way of
223	 * determining reliably whether or not the extended
224	 * functionality is present without hard-coding knowledge
225	 * of specific filesystem implementations.
226	 * Stay in sync with vop_nopoll().
227	 */
228	if (events & ~POLLSTANDARD)
229		return (POLLNVAL);
230
231	return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
232}
233
234#define no_dump		(dumper_t *)enodev
235
236static int
237giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
238{
239	int retval;
240
241	mtx_lock(&Giant);
242	retval = dev->si_devsw->d_gianttrick->
243	    d_open(dev, oflags, devtype, td);
244	mtx_unlock(&Giant);
245	return (retval);
246}
247
248static int
249giant_fdopen(struct cdev *dev, int oflags, struct thread *td, int fdidx)
250{
251	int retval;
252
253	mtx_lock(&Giant);
254	retval = dev->si_devsw->d_gianttrick->
255	    d_fdopen(dev, oflags, td, fdidx);
256	mtx_unlock(&Giant);
257	return (retval);
258}
259
260static int
261giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
262{
263	int retval;
264
265	mtx_lock(&Giant);
266	retval = dev->si_devsw->d_gianttrick->
267	    d_close(dev, fflag, devtype, td);
268	mtx_unlock(&Giant);
269	return (retval);
270}
271
272static void
273giant_strategy(struct bio *bp)
274{
275
276	mtx_lock(&Giant);
277	bp->bio_dev->si_devsw->d_gianttrick->
278	    d_strategy(bp);
279	mtx_unlock(&Giant);
280}
281
282static int
283giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
284{
285	int retval;
286
287	mtx_lock(&Giant);
288	retval = dev->si_devsw->d_gianttrick->
289	    d_ioctl(dev, cmd, data, fflag, td);
290	mtx_unlock(&Giant);
291	return (retval);
292}
293
294static int
295giant_read(struct cdev *dev, struct uio *uio, int ioflag)
296{
297	int retval;
298
299	mtx_lock(&Giant);
300	retval = dev->si_devsw->d_gianttrick->
301	    d_read(dev, uio, ioflag);
302	mtx_unlock(&Giant);
303	return (retval);
304}
305
306static int
307giant_write(struct cdev *dev, struct uio *uio, int ioflag)
308{
309	int retval;
310
311	mtx_lock(&Giant);
312	retval = dev->si_devsw->d_gianttrick->
313		d_write(dev, uio, ioflag);
314	mtx_unlock(&Giant);
315	return (retval);
316}
317
318static int
319giant_poll(struct cdev *dev, int events, struct thread *td)
320{
321	int retval;
322
323	mtx_lock(&Giant);
324	retval = dev->si_devsw->d_gianttrick->
325	    d_poll(dev, events, td);
326	mtx_unlock(&Giant);
327	return (retval);
328}
329
330static int
331giant_kqfilter(struct cdev *dev, struct knote *kn)
332{
333	int retval;
334
335	mtx_lock(&Giant);
336	retval = dev->si_devsw->d_gianttrick->
337	    d_kqfilter(dev, kn);
338	mtx_unlock(&Giant);
339	return (retval);
340}
341
342static int
343giant_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot)
344{
345	int retval;
346
347	mtx_lock(&Giant);
348	retval = dev->si_devsw->d_gianttrick->
349	    d_mmap(dev, offset, paddr, nprot);
350	mtx_unlock(&Giant);
351	return (retval);
352}
353
354
355/*
356 * struct cdev * and u_dev_t primitives
357 */
358
359int
360minor(struct cdev *x)
361{
362	if (x == NULL)
363		return NODEV;
364	return(x->si_drv0 & MAXMINOR);
365}
366
367int
368dev2unit(struct cdev *x)
369{
370
371	if (x == NULL)
372		return NODEV;
373	return (minor2unit(minor(x)));
374}
375
376u_int
377minor2unit(u_int _minor)
378{
379
380	KASSERT((_minor & ~MAXMINOR) == 0, ("Illegal minor %x", _minor));
381	return ((_minor & 0xff) | ((_minor >> 8) & 0xffff00));
382}
383
384int
385unit2minor(int unit)
386{
387
388	KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
389	return ((unit & 0xff) | ((unit << 8) & ~0xffff));
390}
391
392static struct cdev *
393newdev(struct cdevsw *csw, int y, struct cdev *si)
394{
395	struct cdev *si2;
396	dev_t	udev;
397
398	mtx_assert(&devmtx, MA_OWNED);
399	udev = y;
400	LIST_FOREACH(si2, &csw->d_devs, si_list) {
401		if (si2->si_drv0 == udev) {
402			devfs_free(si);
403			return (si2);
404		}
405	}
406	si->si_drv0 = udev;
407	si->si_devsw = csw;
408	LIST_INSERT_HEAD(&csw->d_devs, si, si_list);
409	return (si);
410}
411
412int
413uminor(dev_t dev)
414{
415	return (dev & MAXMINOR);
416}
417
418int
419umajor(dev_t dev)
420{
421	return ((dev & ~MAXMINOR) >> 8);
422}
423
424static void
425fini_cdevsw(struct cdevsw *devsw)
426{
427	struct cdevsw *gt;
428
429	if (devsw->d_gianttrick != NULL) {
430		gt = devsw->d_gianttrick;
431		memcpy(devsw, gt, sizeof *devsw);
432		free(gt, M_DEVT);
433		devsw->d_gianttrick = NULL;
434	}
435	devsw->d_flags &= ~D_INIT;
436}
437
438static void
439prep_cdevsw(struct cdevsw *devsw)
440{
441	struct cdevsw *dsw2;
442
443	if (devsw->d_flags & D_NEEDGIANT)
444		dsw2 = malloc(sizeof *dsw2, M_DEVT, M_WAITOK);
445	else
446		dsw2 = NULL;
447	dev_lock();
448
449	if (devsw->d_version != D_VERSION_01) {
450		printf(
451		    "WARNING: Device driver \"%s\" has wrong version %s\n",
452		    devsw->d_name == NULL ? "???" : devsw->d_name,
453		    "and is disabled.  Recompile KLD module.");
454		devsw->d_open = dead_open;
455		devsw->d_close = dead_close;
456		devsw->d_read = dead_read;
457		devsw->d_write = dead_write;
458		devsw->d_ioctl = dead_ioctl;
459		devsw->d_poll = dead_poll;
460		devsw->d_mmap = dead_mmap;
461		devsw->d_strategy = dead_strategy;
462		devsw->d_dump = dead_dump;
463		devsw->d_kqfilter = dead_kqfilter;
464	}
465
466	if (devsw->d_flags & D_TTY) {
467		if (devsw->d_ioctl == NULL)	devsw->d_ioctl = ttyioctl;
468		if (devsw->d_read == NULL)	devsw->d_read = ttyread;
469		if (devsw->d_write == NULL)	devsw->d_write = ttywrite;
470		if (devsw->d_kqfilter == NULL)	devsw->d_kqfilter = ttykqfilter;
471		if (devsw->d_poll == NULL)	devsw->d_poll = ttypoll;
472	}
473
474	if (devsw->d_flags & D_NEEDGIANT) {
475		if (devsw->d_gianttrick == NULL) {
476			memcpy(dsw2, devsw, sizeof *dsw2);
477			devsw->d_gianttrick = dsw2;
478		} else
479			free(dsw2, M_DEVT);
480	}
481
482#define FIXUP(member, noop, giant) 				\
483	do {							\
484		if (devsw->member == NULL) {			\
485			devsw->member = noop;			\
486		} else if (devsw->d_flags & D_NEEDGIANT)	\
487			devsw->member = giant;			\
488		}						\
489	while (0)
490
491	FIXUP(d_open,		null_open,	giant_open);
492	FIXUP(d_fdopen,		NULL,		giant_fdopen);
493	FIXUP(d_close,		null_close,	giant_close);
494	FIXUP(d_read,		no_read,	giant_read);
495	FIXUP(d_write,		no_write,	giant_write);
496	FIXUP(d_ioctl,		no_ioctl,	giant_ioctl);
497	FIXUP(d_poll,		no_poll,	giant_poll);
498	FIXUP(d_mmap,		no_mmap,	giant_mmap);
499	FIXUP(d_strategy,	no_strategy,	giant_strategy);
500	FIXUP(d_kqfilter,	no_kqfilter,	giant_kqfilter);
501
502	if (devsw->d_dump == NULL)	devsw->d_dump = no_dump;
503
504	LIST_INIT(&devsw->d_devs);
505
506	devsw->d_flags |= D_INIT;
507
508	dev_unlock();
509}
510
511static struct cdev *
512make_dev_credv(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid,
513    gid_t gid, int mode, const char *fmt, va_list ap)
514{
515	struct cdev *dev;
516	int i;
517
518	KASSERT((minornr & ~MAXMINOR) == 0,
519	    ("Invalid minor (0x%x) in make_dev", minornr));
520
521	if (!(devsw->d_flags & D_INIT))
522		prep_cdevsw(devsw);
523	dev = devfs_alloc();
524	dev_lock();
525	dev = newdev(devsw, minornr, dev);
526	if (dev->si_flags & SI_CHEAPCLONE &&
527	    dev->si_flags & SI_NAMED) {
528		/*
529		 * This is allowed as it removes races and generally
530		 * simplifies cloning devices.
531		 * XXX: still ??
532		 */
533		dev_unlock();
534		return (dev);
535	}
536	KASSERT(!(dev->si_flags & SI_NAMED),
537	    ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
538	    devsw->d_name, minor(dev), devtoname(dev)));
539
540	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
541	if (i > (sizeof dev->__si_namebuf - 1)) {
542		printf("WARNING: Device name truncated! (%s)\n",
543		    dev->__si_namebuf);
544	}
545
546	dev->si_flags |= SI_NAMED;
547	if (cr != NULL)
548		dev->si_cred = crhold(cr);
549	else
550		dev->si_cred = NULL;
551	dev->si_uid = uid;
552	dev->si_gid = gid;
553	dev->si_mode = mode;
554
555	devfs_create(dev);
556	dev_unlock();
557	return (dev);
558}
559
560struct cdev *
561make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int mode,
562    const char *fmt, ...)
563{
564	struct cdev *dev;
565	va_list ap;
566
567	va_start(ap, fmt);
568	dev = make_dev_credv(devsw, minornr, NULL, uid, gid, mode, fmt, ap);
569	va_end(ap);
570	return (dev);
571}
572
573struct cdev *
574make_dev_cred(struct cdevsw *devsw, int minornr, struct ucred *cr, uid_t uid,
575    gid_t gid, int mode, const char *fmt, ...)
576{
577	struct cdev *dev;
578	va_list ap;
579
580	va_start(ap, fmt);
581	dev = make_dev_credv(devsw, minornr, cr, uid, gid, mode, fmt, ap);
582	va_end(ap);
583
584	return (dev);
585}
586
587static void
588dev_dependsl(struct cdev *pdev, struct cdev *cdev)
589{
590
591	cdev->si_parent = pdev;
592	cdev->si_flags |= SI_CHILD;
593	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
594}
595
596
597void
598dev_depends(struct cdev *pdev, struct cdev *cdev)
599{
600
601	dev_lock();
602	dev_dependsl(pdev, cdev);
603	dev_unlock();
604}
605
606struct cdev *
607make_dev_alias(struct cdev *pdev, const char *fmt, ...)
608{
609	struct cdev *dev;
610	va_list ap;
611	int i;
612
613	dev = devfs_alloc();
614	dev_lock();
615	dev->si_flags |= SI_ALIAS;
616	dev->si_flags |= SI_NAMED;
617	va_start(ap, fmt);
618	i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
619	if (i > (sizeof dev->__si_namebuf - 1)) {
620		printf("WARNING: Device name truncated! (%s)\n",
621		    dev->__si_namebuf);
622	}
623	va_end(ap);
624
625	devfs_create(dev);
626	dev_unlock();
627	dev_depends(pdev, dev);
628	return (dev);
629}
630
631static void
632destroy_devl(struct cdev *dev)
633{
634	struct cdevsw *csw;
635
636	mtx_assert(&devmtx, MA_OWNED);
637	KASSERT(dev->si_flags & SI_NAMED,
638	    ("WARNING: Driver mistake: destroy_dev on %d\n", minor(dev)));
639
640	devfs_destroy(dev);
641
642	/* Remove name marking */
643	dev->si_flags &= ~SI_NAMED;
644
645	/* If we are a child, remove us from the parents list */
646	if (dev->si_flags & SI_CHILD) {
647		LIST_REMOVE(dev, si_siblings);
648		dev->si_flags &= ~SI_CHILD;
649	}
650
651	/* Kill our children */
652	while (!LIST_EMPTY(&dev->si_children))
653		destroy_devl(LIST_FIRST(&dev->si_children));
654
655	/* Remove from clone list */
656	if (dev->si_flags & SI_CLONELIST) {
657		LIST_REMOVE(dev, si_clone);
658		dev->si_flags &= ~SI_CLONELIST;
659	}
660
661	dev->si_refcount++;	/* Avoid race with dev_rel() */
662	csw = dev->si_devsw;
663	dev->si_devsw = NULL;	/* already NULL for SI_ALIAS */
664	while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
665		csw->d_purge(dev);
666		msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
667		if (dev->si_threadcount)
668			printf("Still %lu threads in %s\n",
669			    dev->si_threadcount, devtoname(dev));
670	}
671	while (dev->si_threadcount != 0) {
672		/* Use unique dummy wait ident */
673		msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10);
674	}
675
676	dev->si_drv1 = 0;
677	dev->si_drv2 = 0;
678	bzero(&dev->__si_u, sizeof(dev->__si_u));
679
680	if (!(dev->si_flags & SI_ALIAS)) {
681		/* Remove from cdevsw list */
682		LIST_REMOVE(dev, si_list);
683
684		/* If cdevsw has no more struct cdev *'s, clean it */
685		if (LIST_EMPTY(&csw->d_devs))
686			fini_cdevsw(csw);
687	}
688	dev->si_flags &= ~SI_ALIAS;
689	dev->si_refcount--;	/* Avoid race with dev_rel() */
690
691	if (dev->si_refcount > 0) {
692		LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
693	} else {
694		devfs_free(dev);
695	}
696}
697
698void
699destroy_dev(struct cdev *dev)
700{
701
702	dev_lock();
703	destroy_devl(dev);
704	dev_unlock();
705}
706
707const char *
708devtoname(struct cdev *dev)
709{
710	char *p;
711	struct cdevsw *csw;
712	int mynor;
713
714	if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
715		p = dev->si_name;
716		csw = dev_refthread(dev);
717		if (csw != NULL) {
718			sprintf(p, "(%s)", csw->d_name);
719			dev_relthread(dev);
720		}
721		p += strlen(p);
722		mynor = minor(dev);
723		if (mynor < 0 || mynor > 255)
724			sprintf(p, "/%#x", (u_int)mynor);
725		else
726			sprintf(p, "/%d", mynor);
727	}
728	return (dev->si_name);
729}
730
731int
732dev_stdclone(char *name, char **namep, const char *stem, int *unit)
733{
734	int u, i;
735
736	i = strlen(stem);
737	if (bcmp(stem, name, i) != 0)
738		return (0);
739	if (!isdigit(name[i]))
740		return (0);
741	u = 0;
742	if (name[i] == '0' && isdigit(name[i+1]))
743		return (0);
744	while (isdigit(name[i])) {
745		u *= 10;
746		u += name[i++] - '0';
747	}
748	if (u > 0xffffff)
749		return (0);
750	*unit = u;
751	if (namep)
752		*namep = &name[i];
753	if (name[i])
754		return (2);
755	return (1);
756}
757
758/*
759 * Helper functions for cloning device drivers.
760 *
761 * The objective here is to make it unnecessary for the device drivers to
762 * use rman or similar to manage their unit number space.  Due to the way
763 * we do "on-demand" devices, using rman or other "private" methods
764 * will be very tricky to lock down properly once we lock down this file.
765 *
766 * Instead we give the drivers these routines which puts the struct cdev *'s
767 * that are to be managed on their own list, and gives the driver the ability
768 * to ask for the first free unit number or a given specified unit number.
769 *
770 * In addition these routines support paired devices (pty, nmdm and similar)
771 * by respecting a number of "flag" bits in the minor number.
772 *
773 */
774
775struct clonedevs {
776	LIST_HEAD(,cdev)	head;
777};
778
779void
780clone_setup(struct clonedevs **cdp)
781{
782
783	*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
784	LIST_INIT(&(*cdp)->head);
785}
786
787int
788clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra)
789{
790	struct clonedevs *cd;
791	struct cdev *dev, *ndev, *dl, *de;
792	int unit, low, u;
793
794	KASSERT(*cdp != NULL,
795	    ("clone_setup() not called in driver \"%s\"", csw->d_name));
796	KASSERT(!(extra & CLONE_UNITMASK),
797	    ("Illegal extra bits (0x%x) in clone_create", extra));
798	KASSERT(*up <= CLONE_UNITMASK,
799	    ("Too high unit (0x%x) in clone_create", *up));
800
801	if (!(csw->d_flags & D_INIT))
802		prep_cdevsw(csw);
803
804	/*
805	 * Search the list for a lot of things in one go:
806	 *   A preexisting match is returned immediately.
807	 *   The lowest free unit number if we are passed -1, and the place
808	 *	 in the list where we should insert that new element.
809	 *   The place to insert a specified unit number, if applicable
810	 *       the end of the list.
811	 */
812	unit = *up;
813	ndev = devfs_alloc();
814	dev_lock();
815	low = extra;
816	de = dl = NULL;
817	cd = *cdp;
818	LIST_FOREACH(dev, &cd->head, si_clone) {
819		KASSERT(dev->si_flags & SI_CLONELIST,
820		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
821		u = dev2unit(dev);
822		if (u == (unit | extra)) {
823			*dp = dev;
824			devfs_free(ndev);
825			dev_unlock();
826			return (0);
827		}
828		if (unit == -1 && u == low) {
829			low++;
830			de = dev;
831			continue;
832		} else if (u < (unit | extra)) {
833			de = dev;
834			continue;
835		} else if (u > (unit | extra)) {
836			dl = dev;
837			break;
838		}
839	}
840	if (unit == -1)
841		unit = low & CLONE_UNITMASK;
842	dev = newdev(csw, unit2minor(unit | extra), ndev);
843	if (dev->si_flags & SI_CLONELIST) {
844		printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
845		printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra);
846		LIST_FOREACH(dev, &cd->head, si_clone) {
847			printf("\t%p %s\n", dev, dev->si_name);
848		}
849		panic("foo");
850	}
851	KASSERT(!(dev->si_flags & SI_CLONELIST),
852	    ("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
853	if (dl != NULL)
854		LIST_INSERT_BEFORE(dl, dev, si_clone);
855	else if (de != NULL)
856		LIST_INSERT_AFTER(de, dev, si_clone);
857	else
858		LIST_INSERT_HEAD(&cd->head, dev, si_clone);
859	dev->si_flags |= SI_CLONELIST;
860	*up = unit;
861	dev_unlock();
862	return (1);
863}
864
865/*
866 * Kill everything still on the list.  The driver should already have
867 * disposed of any softc hung of the struct cdev *'s at this time.
868 */
869void
870clone_cleanup(struct clonedevs **cdp)
871{
872	struct cdev *dev, *tdev;
873	struct clonedevs *cd;
874
875	cd = *cdp;
876	if (cd == NULL)
877		return;
878	dev_lock();
879	LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) {
880		KASSERT(dev->si_flags & SI_CLONELIST,
881		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
882		KASSERT(dev->si_flags & SI_NAMED,
883		    ("Driver has goofed in cloning underways udev %x", dev->si_drv0));
884		destroy_devl(dev);
885	}
886	dev_unlock();
887	free(cd, M_DEVBUF);
888	*cdp = NULL;
889}
890