xref: /freebsd/sys/kern/kern_conf.c (revision f18976136625a7d016e97bfd9eabddf640b3e06d)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 1999-2002 Poul-Henning Kamp
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/systm.h>
35 #include <sys/bus.h>
36 #include <sys/bio.h>
37 #include <sys/lock.h>
38 #include <sys/mutex.h>
39 #include <sys/module.h>
40 #include <sys/malloc.h>
41 #include <sys/conf.h>
42 #include <sys/vnode.h>
43 #include <sys/queue.h>
44 #include <sys/poll.h>
45 #include <sys/sx.h>
46 #include <sys/ctype.h>
47 #include <sys/ucred.h>
48 #include <sys/taskqueue.h>
49 #include <machine/stdarg.h>
50 
51 #include <fs/devfs/devfs_int.h>
52 #include <vm/vm.h>
53 
54 static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
55 
56 struct mtx devmtx;
57 static void destroy_devl(struct cdev *dev);
58 static int destroy_dev_sched_cbl(struct cdev *dev,
59     void (*cb)(void *), void *arg);
60 static void destroy_dev_tq(void *ctx, int pending);
61 static int make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw,
62     int unit, struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
63     va_list ap);
64 
65 static struct cdev_priv_list cdevp_free_list =
66     TAILQ_HEAD_INITIALIZER(cdevp_free_list);
67 static SLIST_HEAD(free_cdevsw, cdevsw) cdevsw_gt_post_list =
68     SLIST_HEAD_INITIALIZER(cdevsw_gt_post_list);
69 
70 void
71 dev_lock(void)
72 {
73 
74 	mtx_lock(&devmtx);
75 }
76 
77 /*
78  * Free all the memory collected while the cdev mutex was
79  * locked. Since devmtx is after the system map mutex, free() cannot
80  * be called immediately and is postponed until cdev mutex can be
81  * dropped.
82  */
83 static void
84 dev_unlock_and_free(void)
85 {
86 	struct cdev_priv_list cdp_free;
87 	struct free_cdevsw csw_free;
88 	struct cdev_priv *cdp;
89 	struct cdevsw *csw;
90 
91 	mtx_assert(&devmtx, MA_OWNED);
92 
93 	/*
94 	 * Make the local copy of the list heads while the dev_mtx is
95 	 * held. Free it later.
96 	 */
97 	TAILQ_INIT(&cdp_free);
98 	TAILQ_CONCAT(&cdp_free, &cdevp_free_list, cdp_list);
99 	csw_free = cdevsw_gt_post_list;
100 	SLIST_INIT(&cdevsw_gt_post_list);
101 
102 	mtx_unlock(&devmtx);
103 
104 	while ((cdp = TAILQ_FIRST(&cdp_free)) != NULL) {
105 		TAILQ_REMOVE(&cdp_free, cdp, cdp_list);
106 		devfs_free(&cdp->cdp_c);
107 	}
108 	while ((csw = SLIST_FIRST(&csw_free)) != NULL) {
109 		SLIST_REMOVE_HEAD(&csw_free, d_postfree_list);
110 		free(csw, M_DEVT);
111 	}
112 }
113 
114 static void
115 dev_free_devlocked(struct cdev *cdev)
116 {
117 	struct cdev_priv *cdp;
118 
119 	mtx_assert(&devmtx, MA_OWNED);
120 	cdp = cdev2priv(cdev);
121 	KASSERT((cdp->cdp_flags & CDP_UNREF_DTR) == 0,
122 	    ("destroy_dev() was not called after delist_dev(%p)", cdev));
123 	TAILQ_INSERT_HEAD(&cdevp_free_list, cdp, cdp_list);
124 }
125 
126 static void
127 cdevsw_free_devlocked(struct cdevsw *csw)
128 {
129 
130 	mtx_assert(&devmtx, MA_OWNED);
131 	SLIST_INSERT_HEAD(&cdevsw_gt_post_list, csw, d_postfree_list);
132 }
133 
134 void
135 dev_unlock(void)
136 {
137 
138 	mtx_unlock(&devmtx);
139 }
140 
141 void
142 dev_ref(struct cdev *dev)
143 {
144 
145 	mtx_assert(&devmtx, MA_NOTOWNED);
146 	mtx_lock(&devmtx);
147 	dev->si_refcount++;
148 	mtx_unlock(&devmtx);
149 }
150 
151 void
152 dev_refl(struct cdev *dev)
153 {
154 
155 	mtx_assert(&devmtx, MA_OWNED);
156 	dev->si_refcount++;
157 }
158 
159 void
160 dev_rel(struct cdev *dev)
161 {
162 	int flag = 0;
163 
164 	mtx_assert(&devmtx, MA_NOTOWNED);
165 	dev_lock();
166 	dev->si_refcount--;
167 	KASSERT(dev->si_refcount >= 0,
168 	    ("dev_rel(%s) gave negative count", devtoname(dev)));
169 	if (dev->si_devsw == NULL && dev->si_refcount == 0) {
170 		LIST_REMOVE(dev, si_list);
171 		flag = 1;
172 	}
173 	dev_unlock();
174 	if (flag)
175 		devfs_free(dev);
176 }
177 
178 struct cdevsw *
179 dev_refthread(struct cdev *dev, int *ref)
180 {
181 	struct cdevsw *csw;
182 	struct cdev_priv *cdp;
183 
184 	mtx_assert(&devmtx, MA_NOTOWNED);
185 	if ((dev->si_flags & SI_ETERNAL) != 0) {
186 		*ref = 0;
187 		return (dev->si_devsw);
188 	}
189 	dev_lock();
190 	csw = dev->si_devsw;
191 	if (csw != NULL) {
192 		cdp = cdev2priv(dev);
193 		if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0)
194 			atomic_add_long(&dev->si_threadcount, 1);
195 		else
196 			csw = NULL;
197 	}
198 	dev_unlock();
199 	if (csw != NULL)
200 		*ref = 1;
201 	return (csw);
202 }
203 
204 struct cdevsw *
205 devvn_refthread(struct vnode *vp, struct cdev **devp, int *ref)
206 {
207 	struct cdevsw *csw;
208 	struct cdev_priv *cdp;
209 	struct cdev *dev;
210 
211 	mtx_assert(&devmtx, MA_NOTOWNED);
212 	if ((vp->v_vflag & VV_ETERNALDEV) != 0) {
213 		dev = vp->v_rdev;
214 		if (dev == NULL)
215 			return (NULL);
216 		KASSERT((dev->si_flags & SI_ETERNAL) != 0,
217 		    ("Not eternal cdev"));
218 		*ref = 0;
219 		csw = dev->si_devsw;
220 		KASSERT(csw != NULL, ("Eternal cdev is destroyed"));
221 		*devp = dev;
222 		return (csw);
223 	}
224 
225 	csw = NULL;
226 	dev_lock();
227 	dev = vp->v_rdev;
228 	if (dev == NULL) {
229 		dev_unlock();
230 		return (NULL);
231 	}
232 	cdp = cdev2priv(dev);
233 	if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0) {
234 		csw = dev->si_devsw;
235 		if (csw != NULL)
236 			atomic_add_long(&dev->si_threadcount, 1);
237 	}
238 	dev_unlock();
239 	if (csw != NULL) {
240 		*devp = dev;
241 		*ref = 1;
242 	}
243 	return (csw);
244 }
245 
246 void
247 dev_relthread(struct cdev *dev, int ref)
248 {
249 
250 	mtx_assert(&devmtx, MA_NOTOWNED);
251 	if (!ref)
252 		return;
253 	KASSERT(dev->si_threadcount > 0,
254 	    ("%s threadcount is wrong", dev->si_name));
255 	atomic_subtract_rel_long(&dev->si_threadcount, 1);
256 }
257 
258 int
259 nullop(void)
260 {
261 
262 	return (0);
263 }
264 
265 int
266 eopnotsupp(void)
267 {
268 
269 	return (EOPNOTSUPP);
270 }
271 
272 static int
273 enxio(void)
274 {
275 	return (ENXIO);
276 }
277 
278 static int
279 enodev(void)
280 {
281 	return (ENODEV);
282 }
283 
284 /* Define a dead_cdevsw for use when devices leave unexpectedly. */
285 
286 #define dead_open	(d_open_t *)enxio
287 #define dead_close	(d_close_t *)enxio
288 #define dead_read	(d_read_t *)enxio
289 #define dead_write	(d_write_t *)enxio
290 #define dead_ioctl	(d_ioctl_t *)enxio
291 #define dead_poll	(d_poll_t *)enodev
292 #define dead_mmap	(d_mmap_t *)enodev
293 
294 static void
295 dead_strategy(struct bio *bp)
296 {
297 
298 	biofinish(bp, NULL, ENXIO);
299 }
300 
301 #define dead_dump	(dumper_t *)enxio
302 #define dead_kqfilter	(d_kqfilter_t *)enxio
303 #define dead_mmap_single (d_mmap_single_t *)enodev
304 
305 static struct cdevsw dead_cdevsw = {
306 	.d_version =	D_VERSION,
307 	.d_open =	dead_open,
308 	.d_close =	dead_close,
309 	.d_read =	dead_read,
310 	.d_write =	dead_write,
311 	.d_ioctl =	dead_ioctl,
312 	.d_poll =	dead_poll,
313 	.d_mmap =	dead_mmap,
314 	.d_strategy =	dead_strategy,
315 	.d_name =	"dead",
316 	.d_dump =	dead_dump,
317 	.d_kqfilter =	dead_kqfilter,
318 	.d_mmap_single = dead_mmap_single
319 };
320 
321 /* Default methods if driver does not specify method */
322 
323 #define null_open	(d_open_t *)nullop
324 #define null_close	(d_close_t *)nullop
325 #define no_read		(d_read_t *)enodev
326 #define no_write	(d_write_t *)enodev
327 #define no_ioctl	(d_ioctl_t *)enodev
328 #define no_mmap		(d_mmap_t *)enodev
329 #define no_kqfilter	(d_kqfilter_t *)enodev
330 #define no_mmap_single	(d_mmap_single_t *)enodev
331 
332 static void
333 no_strategy(struct bio *bp)
334 {
335 
336 	biofinish(bp, NULL, ENODEV);
337 }
338 
339 static int
340 no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
341 {
342 
343 	return (poll_no_poll(events));
344 }
345 
346 #define no_dump		(dumper_t *)enodev
347 
348 static int
349 giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
350 {
351 	struct cdevsw *dsw;
352 	int ref, retval;
353 
354 	dsw = dev_refthread(dev, &ref);
355 	if (dsw == NULL)
356 		return (ENXIO);
357 	mtx_lock(&Giant);
358 	retval = dsw->d_gianttrick->d_open(dev, oflags, devtype, td);
359 	mtx_unlock(&Giant);
360 	dev_relthread(dev, ref);
361 	return (retval);
362 }
363 
364 static int
365 giant_fdopen(struct cdev *dev, int oflags, struct thread *td, struct file *fp)
366 {
367 	struct cdevsw *dsw;
368 	int ref, retval;
369 
370 	dsw = dev_refthread(dev, &ref);
371 	if (dsw == NULL)
372 		return (ENXIO);
373 	mtx_lock(&Giant);
374 	retval = dsw->d_gianttrick->d_fdopen(dev, oflags, td, fp);
375 	mtx_unlock(&Giant);
376 	dev_relthread(dev, ref);
377 	return (retval);
378 }
379 
380 static int
381 giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
382 {
383 	struct cdevsw *dsw;
384 	int ref, retval;
385 
386 	dsw = dev_refthread(dev, &ref);
387 	if (dsw == NULL)
388 		return (ENXIO);
389 	mtx_lock(&Giant);
390 	retval = dsw->d_gianttrick->d_close(dev, fflag, devtype, td);
391 	mtx_unlock(&Giant);
392 	dev_relthread(dev, ref);
393 	return (retval);
394 }
395 
396 static void
397 giant_strategy(struct bio *bp)
398 {
399 	struct cdevsw *dsw;
400 	struct cdev *dev;
401 	int ref;
402 
403 	dev = bp->bio_dev;
404 	dsw = dev_refthread(dev, &ref);
405 	if (dsw == NULL) {
406 		biofinish(bp, NULL, ENXIO);
407 		return;
408 	}
409 	mtx_lock(&Giant);
410 	dsw->d_gianttrick->d_strategy(bp);
411 	mtx_unlock(&Giant);
412 	dev_relthread(dev, ref);
413 }
414 
415 static int
416 giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
417 {
418 	struct cdevsw *dsw;
419 	int ref, retval;
420 
421 	dsw = dev_refthread(dev, &ref);
422 	if (dsw == NULL)
423 		return (ENXIO);
424 	mtx_lock(&Giant);
425 	retval = dsw->d_gianttrick->d_ioctl(dev, cmd, data, fflag, td);
426 	mtx_unlock(&Giant);
427 	dev_relthread(dev, ref);
428 	return (retval);
429 }
430 
431 static int
432 giant_read(struct cdev *dev, struct uio *uio, int ioflag)
433 {
434 	struct cdevsw *dsw;
435 	int ref, retval;
436 
437 	dsw = dev_refthread(dev, &ref);
438 	if (dsw == NULL)
439 		return (ENXIO);
440 	mtx_lock(&Giant);
441 	retval = dsw->d_gianttrick->d_read(dev, uio, ioflag);
442 	mtx_unlock(&Giant);
443 	dev_relthread(dev, ref);
444 	return (retval);
445 }
446 
447 static int
448 giant_write(struct cdev *dev, struct uio *uio, int ioflag)
449 {
450 	struct cdevsw *dsw;
451 	int ref, retval;
452 
453 	dsw = dev_refthread(dev, &ref);
454 	if (dsw == NULL)
455 		return (ENXIO);
456 	mtx_lock(&Giant);
457 	retval = dsw->d_gianttrick->d_write(dev, uio, ioflag);
458 	mtx_unlock(&Giant);
459 	dev_relthread(dev, ref);
460 	return (retval);
461 }
462 
463 static int
464 giant_poll(struct cdev *dev, int events, struct thread *td)
465 {
466 	struct cdevsw *dsw;
467 	int ref, retval;
468 
469 	dsw = dev_refthread(dev, &ref);
470 	if (dsw == NULL)
471 		return (ENXIO);
472 	mtx_lock(&Giant);
473 	retval = dsw->d_gianttrick->d_poll(dev, events, td);
474 	mtx_unlock(&Giant);
475 	dev_relthread(dev, ref);
476 	return (retval);
477 }
478 
479 static int
480 giant_kqfilter(struct cdev *dev, struct knote *kn)
481 {
482 	struct cdevsw *dsw;
483 	int ref, retval;
484 
485 	dsw = dev_refthread(dev, &ref);
486 	if (dsw == NULL)
487 		return (ENXIO);
488 	mtx_lock(&Giant);
489 	retval = dsw->d_gianttrick->d_kqfilter(dev, kn);
490 	mtx_unlock(&Giant);
491 	dev_relthread(dev, ref);
492 	return (retval);
493 }
494 
495 static int
496 giant_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, int nprot,
497     vm_memattr_t *memattr)
498 {
499 	struct cdevsw *dsw;
500 	int ref, retval;
501 
502 	dsw = dev_refthread(dev, &ref);
503 	if (dsw == NULL)
504 		return (ENXIO);
505 	mtx_lock(&Giant);
506 	retval = dsw->d_gianttrick->d_mmap(dev, offset, paddr, nprot,
507 	    memattr);
508 	mtx_unlock(&Giant);
509 	dev_relthread(dev, ref);
510 	return (retval);
511 }
512 
513 static int
514 giant_mmap_single(struct cdev *dev, vm_ooffset_t *offset, vm_size_t size,
515     vm_object_t *object, int nprot)
516 {
517 	struct cdevsw *dsw;
518 	int ref, retval;
519 
520 	dsw = dev_refthread(dev, &ref);
521 	if (dsw == NULL)
522 		return (ENXIO);
523 	mtx_lock(&Giant);
524 	retval = dsw->d_gianttrick->d_mmap_single(dev, offset, size, object,
525 	    nprot);
526 	mtx_unlock(&Giant);
527 	dev_relthread(dev, ref);
528 	return (retval);
529 }
530 
531 static void
532 notify(struct cdev *dev, const char *ev, int flags)
533 {
534 	static const char prefix[] = "cdev=";
535 	char *data;
536 	int namelen, mflags;
537 
538 	if (cold)
539 		return;
540 	mflags = (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK;
541 	namelen = strlen(dev->si_name);
542 	data = malloc(namelen + sizeof(prefix), M_TEMP, mflags);
543 	if (data == NULL)
544 		return;
545 	memcpy(data, prefix, sizeof(prefix) - 1);
546 	memcpy(data + sizeof(prefix) - 1, dev->si_name, namelen + 1);
547 	devctl_notify_f("DEVFS", "CDEV", ev, data, mflags);
548 	free(data, M_TEMP);
549 }
550 
551 static void
552 notify_create(struct cdev *dev, int flags)
553 {
554 
555 	notify(dev, "CREATE", flags);
556 }
557 
558 static void
559 notify_destroy(struct cdev *dev)
560 {
561 
562 	notify(dev, "DESTROY", MAKEDEV_WAITOK);
563 }
564 
565 static struct cdev *
566 newdev(struct make_dev_args *args, struct cdev *si)
567 {
568 	struct cdev *si2;
569 	struct cdevsw *csw;
570 
571 	mtx_assert(&devmtx, MA_OWNED);
572 	csw = args->mda_devsw;
573 	si2 = NULL;
574 	if (csw->d_flags & D_NEEDMINOR) {
575 		/* We may want to return an existing device */
576 		LIST_FOREACH(si2, &csw->d_devs, si_list) {
577 			if (dev2unit(si2) == args->mda_unit) {
578 				dev_free_devlocked(si);
579 				si = si2;
580 				break;
581 			}
582 		}
583 
584 		/*
585 		 * If we're returning an existing device, we should make sure
586 		 * it isn't already initialized.  This would have been caught
587 		 * in consumers anyways, but it's good to catch such a case
588 		 * early.  We still need to complete initialization of the
589 		 * device, and we'll use whatever make_dev_args were passed in
590 		 * to do so.
591 		 */
592 		KASSERT(si2 == NULL || (si2->si_flags & SI_NAMED) == 0,
593 		    ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
594 		    args->mda_devsw->d_name, dev2unit(si2), devtoname(si2)));
595 	}
596 	si->si_drv0 = args->mda_unit;
597 	si->si_drv1 = args->mda_si_drv1;
598 	si->si_drv2 = args->mda_si_drv2;
599 	/* Only push to csw->d_devs if it's not a cloned device. */
600 	if (si2 == NULL) {
601 		si->si_devsw = csw;
602 		LIST_INSERT_HEAD(&csw->d_devs, si, si_list);
603 	} else {
604 		KASSERT(si->si_devsw == csw,
605 		    ("%s: inconsistent devsw between clone_create() and make_dev()",
606 		    __func__));
607 	}
608 	return (si);
609 }
610 
611 static void
612 fini_cdevsw(struct cdevsw *devsw)
613 {
614 	struct cdevsw *gt;
615 
616 	if (devsw->d_gianttrick != NULL) {
617 		gt = devsw->d_gianttrick;
618 		memcpy(devsw, gt, sizeof *devsw);
619 		cdevsw_free_devlocked(gt);
620 		devsw->d_gianttrick = NULL;
621 	}
622 	devsw->d_flags &= ~D_INIT;
623 }
624 
625 static int
626 prep_cdevsw(struct cdevsw *devsw, int flags)
627 {
628 	struct cdevsw *dsw2;
629 
630 	mtx_assert(&devmtx, MA_OWNED);
631 	if (devsw->d_flags & D_INIT)
632 		return (0);
633 	if (devsw->d_flags & D_NEEDGIANT) {
634 		dev_unlock();
635 		dsw2 = malloc(sizeof *dsw2, M_DEVT,
636 		     (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK);
637 		dev_lock();
638 		if (dsw2 == NULL && !(devsw->d_flags & D_INIT))
639 			return (ENOMEM);
640 	} else
641 		dsw2 = NULL;
642 	if (devsw->d_flags & D_INIT) {
643 		if (dsw2 != NULL)
644 			cdevsw_free_devlocked(dsw2);
645 		return (0);
646 	}
647 
648 	if (devsw->d_version != D_VERSION_04) {
649 		printf(
650 		    "WARNING: Device driver \"%s\" has wrong version %s\n",
651 		    devsw->d_name == NULL ? "???" : devsw->d_name,
652 		    "and is disabled.  Recompile KLD module.");
653 		devsw->d_open = dead_open;
654 		devsw->d_close = dead_close;
655 		devsw->d_read = dead_read;
656 		devsw->d_write = dead_write;
657 		devsw->d_ioctl = dead_ioctl;
658 		devsw->d_poll = dead_poll;
659 		devsw->d_mmap = dead_mmap;
660 		devsw->d_mmap_single = dead_mmap_single;
661 		devsw->d_strategy = dead_strategy;
662 		devsw->d_dump = dead_dump;
663 		devsw->d_kqfilter = dead_kqfilter;
664 	}
665 
666 	if (devsw->d_flags & D_NEEDGIANT) {
667 		if (devsw->d_gianttrick == NULL) {
668 			memcpy(dsw2, devsw, sizeof *dsw2);
669 			devsw->d_gianttrick = dsw2;
670 			dsw2 = NULL;
671 		}
672 	}
673 
674 #define FIXUP(member, noop, giant) 				\
675 	do {							\
676 		if (devsw->member == NULL) {			\
677 			devsw->member = noop;			\
678 		} else if (devsw->d_flags & D_NEEDGIANT)	\
679 			devsw->member = giant;			\
680 		}						\
681 	while (0)
682 
683 	FIXUP(d_open,		null_open,	giant_open);
684 	FIXUP(d_fdopen,		NULL,		giant_fdopen);
685 	FIXUP(d_close,		null_close,	giant_close);
686 	FIXUP(d_read,		no_read,	giant_read);
687 	FIXUP(d_write,		no_write,	giant_write);
688 	FIXUP(d_ioctl,		no_ioctl,	giant_ioctl);
689 	FIXUP(d_poll,		no_poll,	giant_poll);
690 	FIXUP(d_mmap,		no_mmap,	giant_mmap);
691 	FIXUP(d_strategy,	no_strategy,	giant_strategy);
692 	FIXUP(d_kqfilter,	no_kqfilter,	giant_kqfilter);
693 	FIXUP(d_mmap_single,	no_mmap_single,	giant_mmap_single);
694 
695 	if (devsw->d_dump == NULL)	devsw->d_dump = no_dump;
696 
697 	LIST_INIT(&devsw->d_devs);
698 
699 	devsw->d_flags |= D_INIT;
700 
701 	if (dsw2 != NULL)
702 		cdevsw_free_devlocked(dsw2);
703 	return (0);
704 }
705 
706 static int
707 prep_devname(struct cdev *dev, const char *fmt, va_list ap)
708 {
709 	int len;
710 	char *from, *q, *s, *to;
711 
712 	mtx_assert(&devmtx, MA_OWNED);
713 
714 	len = vsnrprintf(dev->si_name, sizeof(dev->si_name), 32, fmt, ap);
715 	if (len > sizeof(dev->si_name) - 1)
716 		return (ENAMETOOLONG);
717 
718 	/* Strip leading slashes. */
719 	for (from = dev->si_name; *from == '/'; from++)
720 		;
721 
722 	for (to = dev->si_name; *from != '\0'; from++, to++) {
723 		/*
724 		 * Spaces and double quotation marks cause
725 		 * problems for the devctl(4) protocol.
726 		 * Reject names containing those characters.
727 		 */
728 		if (isspace(*from) || *from == '"')
729 			return (EINVAL);
730 		/* Treat multiple sequential slashes as single. */
731 		while (from[0] == '/' && from[1] == '/')
732 			from++;
733 		/* Trailing slash is considered invalid. */
734 		if (from[0] == '/' && from[1] == '\0')
735 			return (EINVAL);
736 		*to = *from;
737 	}
738 	*to = '\0';
739 
740 	if (dev->si_name[0] == '\0')
741 		return (EINVAL);
742 
743 	/* Disallow "." and ".." components. */
744 	for (s = dev->si_name;;) {
745 		for (q = s; *q != '/' && *q != '\0'; q++)
746 			;
747 		if (q - s == 1 && s[0] == '.')
748 			return (EINVAL);
749 		if (q - s == 2 && s[0] == '.' && s[1] == '.')
750 			return (EINVAL);
751 		if (*q != '/')
752 			break;
753 		s = q + 1;
754 	}
755 
756 	if (devfs_dev_exists(dev->si_name) != 0)
757 		return (EEXIST);
758 
759 	return (0);
760 }
761 
762 void
763 make_dev_args_init_impl(struct make_dev_args *args, size_t sz)
764 {
765 
766 	bzero(args, sz);
767 	args->mda_size = sz;
768 }
769 
770 static int
771 make_dev_sv(struct make_dev_args *args1, struct cdev **dres,
772     const char *fmt, va_list ap)
773 {
774 	struct cdev *dev, *dev_new;
775 	struct make_dev_args args;
776 	int res;
777 
778 	bzero(&args, sizeof(args));
779 	if (sizeof(args) < args1->mda_size)
780 		return (EINVAL);
781 	bcopy(args1, &args, args1->mda_size);
782 	KASSERT((args.mda_flags & MAKEDEV_WAITOK) == 0 ||
783 	    (args.mda_flags & MAKEDEV_NOWAIT) == 0,
784 	    ("make_dev_sv: both WAITOK and NOWAIT specified"));
785 	dev_new = devfs_alloc(args.mda_flags);
786 	if (dev_new == NULL)
787 		return (ENOMEM);
788 	dev_lock();
789 	res = prep_cdevsw(args.mda_devsw, args.mda_flags);
790 	if (res != 0) {
791 		dev_unlock();
792 		devfs_free(dev_new);
793 		return (res);
794 	}
795 	dev = newdev(&args, dev_new);
796 	if ((dev->si_flags & SI_NAMED) == 0) {
797 		res = prep_devname(dev, fmt, ap);
798 		if (res != 0) {
799 			if ((args.mda_flags & MAKEDEV_CHECKNAME) == 0) {
800 				panic(
801 			"make_dev_sv: bad si_name (error=%d, si_name=%s)",
802 				    res, dev->si_name);
803 			}
804 			if (dev == dev_new) {
805 				LIST_REMOVE(dev, si_list);
806 				dev_unlock();
807 				devfs_free(dev);
808 			} else
809 				dev_unlock();
810 			return (res);
811 		}
812 	}
813 	if ((args.mda_flags & MAKEDEV_REF) != 0)
814 		dev_refl(dev);
815 	if ((args.mda_flags & MAKEDEV_ETERNAL) != 0)
816 		dev->si_flags |= SI_ETERNAL;
817 	KASSERT(!(dev->si_flags & SI_NAMED),
818 	    ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
819 	    args.mda_devsw->d_name, dev2unit(dev), devtoname(dev)));
820 	dev->si_flags |= SI_NAMED;
821 	if (args.mda_cr != NULL)
822 		dev->si_cred = crhold(args.mda_cr);
823 	dev->si_uid = args.mda_uid;
824 	dev->si_gid = args.mda_gid;
825 	dev->si_mode = args.mda_mode;
826 
827 	devfs_create(dev);
828 	clean_unrhdrl(devfs_inos);
829 	dev_unlock_and_free();
830 
831 	notify_create(dev, args.mda_flags);
832 
833 	*dres = dev;
834 	return (0);
835 }
836 
837 int
838 make_dev_s(struct make_dev_args *args, struct cdev **dres,
839     const char *fmt, ...)
840 {
841 	va_list ap;
842 	int res;
843 
844 	va_start(ap, fmt);
845 	res = make_dev_sv(args, dres, fmt, ap);
846 	va_end(ap);
847 	return (res);
848 }
849 
850 static int
851 make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw, int unit,
852     struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
853     va_list ap)
854 {
855 	struct make_dev_args args;
856 
857 	make_dev_args_init(&args);
858 	args.mda_flags = flags;
859 	args.mda_devsw = devsw;
860 	args.mda_cr = cr;
861 	args.mda_uid = uid;
862 	args.mda_gid = gid;
863 	args.mda_mode = mode;
864 	args.mda_unit = unit;
865 	return (make_dev_sv(&args, dres, fmt, ap));
866 }
867 
868 struct cdev *
869 make_dev(struct cdevsw *devsw, int unit, uid_t uid, gid_t gid, int mode,
870     const char *fmt, ...)
871 {
872 	struct cdev *dev;
873 	va_list ap;
874 	int res __unused;
875 
876 	va_start(ap, fmt);
877 	res = make_dev_credv(0, &dev, devsw, unit, NULL, uid, gid, mode, fmt,
878 		      ap);
879 	va_end(ap);
880 	KASSERT(res == 0 && dev != NULL,
881 	    ("make_dev: failed make_dev_credv (error=%d)", res));
882 	return (dev);
883 }
884 
885 struct cdev *
886 make_dev_cred(struct cdevsw *devsw, int unit, struct ucred *cr, uid_t uid,
887     gid_t gid, int mode, const char *fmt, ...)
888 {
889 	struct cdev *dev;
890 	va_list ap;
891 	int res __unused;
892 
893 	va_start(ap, fmt);
894 	res = make_dev_credv(0, &dev, devsw, unit, cr, uid, gid, mode, fmt, ap);
895 	va_end(ap);
896 
897 	KASSERT(res == 0 && dev != NULL,
898 	    ("make_dev_cred: failed make_dev_credv (error=%d)", res));
899 	return (dev);
900 }
901 
902 struct cdev *
903 make_dev_credf(int flags, struct cdevsw *devsw, int unit, struct ucred *cr,
904     uid_t uid, gid_t gid, int mode, const char *fmt, ...)
905 {
906 	struct cdev *dev;
907 	va_list ap;
908 	int res;
909 
910 	va_start(ap, fmt);
911 	res = make_dev_credv(flags, &dev, devsw, unit, cr, uid, gid, mode,
912 	    fmt, ap);
913 	va_end(ap);
914 
915 	KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
916 	    ((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
917 	    ("make_dev_credf: failed make_dev_credv (error=%d)", res));
918 	return (res == 0 ? dev : NULL);
919 }
920 
921 int
922 make_dev_p(int flags, struct cdev **cdev, struct cdevsw *devsw,
923     struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt, ...)
924 {
925 	va_list ap;
926 	int res;
927 
928 	va_start(ap, fmt);
929 	res = make_dev_credv(flags, cdev, devsw, 0, cr, uid, gid, mode,
930 	    fmt, ap);
931 	va_end(ap);
932 
933 	KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
934 	    ((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
935 	    ("make_dev_p: failed make_dev_credv (error=%d)", res));
936 	return (res);
937 }
938 
939 static void
940 dev_dependsl(struct cdev *pdev, struct cdev *cdev)
941 {
942 
943 	cdev->si_parent = pdev;
944 	cdev->si_flags |= SI_CHILD;
945 	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
946 }
947 
948 
949 void
950 dev_depends(struct cdev *pdev, struct cdev *cdev)
951 {
952 
953 	dev_lock();
954 	dev_dependsl(pdev, cdev);
955 	dev_unlock();
956 }
957 
958 static int
959 make_dev_alias_v(int flags, struct cdev **cdev, struct cdev *pdev,
960     const char *fmt, va_list ap)
961 {
962 	struct cdev *dev;
963 	int error;
964 
965 	KASSERT(pdev != NULL, ("make_dev_alias_v: pdev is NULL"));
966 	KASSERT((flags & MAKEDEV_WAITOK) == 0 || (flags & MAKEDEV_NOWAIT) == 0,
967 	    ("make_dev_alias_v: both WAITOK and NOWAIT specified"));
968 	KASSERT((flags & ~(MAKEDEV_WAITOK | MAKEDEV_NOWAIT |
969 	    MAKEDEV_CHECKNAME)) == 0,
970 	    ("make_dev_alias_v: invalid flags specified (flags=%02x)", flags));
971 
972 	dev = devfs_alloc(flags);
973 	if (dev == NULL)
974 		return (ENOMEM);
975 	dev_lock();
976 	dev->si_flags |= SI_ALIAS;
977 	error = prep_devname(dev, fmt, ap);
978 	if (error != 0) {
979 		if ((flags & MAKEDEV_CHECKNAME) == 0) {
980 			panic("make_dev_alias_v: bad si_name "
981 			    "(error=%d, si_name=%s)", error, dev->si_name);
982 		}
983 		dev_unlock();
984 		devfs_free(dev);
985 		return (error);
986 	}
987 	dev->si_flags |= SI_NAMED;
988 	devfs_create(dev);
989 	dev_dependsl(pdev, dev);
990 	clean_unrhdrl(devfs_inos);
991 	dev_unlock();
992 
993 	notify_create(dev, flags);
994 	*cdev = dev;
995 
996 	return (0);
997 }
998 
999 struct cdev *
1000 make_dev_alias(struct cdev *pdev, const char *fmt, ...)
1001 {
1002 	struct cdev *dev;
1003 	va_list ap;
1004 	int res __unused;
1005 
1006 	va_start(ap, fmt);
1007 	res = make_dev_alias_v(MAKEDEV_WAITOK, &dev, pdev, fmt, ap);
1008 	va_end(ap);
1009 
1010 	KASSERT(res == 0 && dev != NULL,
1011 	    ("make_dev_alias: failed make_dev_alias_v (error=%d)", res));
1012 	return (dev);
1013 }
1014 
1015 int
1016 make_dev_alias_p(int flags, struct cdev **cdev, struct cdev *pdev,
1017     const char *fmt, ...)
1018 {
1019 	va_list ap;
1020 	int res;
1021 
1022 	va_start(ap, fmt);
1023 	res = make_dev_alias_v(flags, cdev, pdev, fmt, ap);
1024 	va_end(ap);
1025 	return (res);
1026 }
1027 
1028 int
1029 make_dev_physpath_alias(int flags, struct cdev **cdev, struct cdev *pdev,
1030     struct cdev *old_alias, const char *physpath)
1031 {
1032 	char *devfspath;
1033 	int physpath_len;
1034 	int max_parentpath_len;
1035 	int parentpath_len;
1036 	int devfspathbuf_len;
1037 	int mflags;
1038 	int ret;
1039 
1040 	*cdev = NULL;
1041 	devfspath = NULL;
1042 	physpath_len = strlen(physpath);
1043 	ret = EINVAL;
1044 	if (physpath_len == 0)
1045 		goto out;
1046 
1047 	if (strncmp("id1,", physpath, 4) == 0) {
1048 		physpath += 4;
1049 		physpath_len -= 4;
1050 		if (physpath_len == 0)
1051 			goto out;
1052 	}
1053 
1054 	max_parentpath_len = SPECNAMELEN - physpath_len - /*/*/1;
1055 	parentpath_len = strlen(pdev->si_name);
1056 	if (max_parentpath_len < parentpath_len) {
1057 		if (bootverbose)
1058 			printf("WARNING: Unable to alias %s "
1059 			    "to %s/%s - path too long\n",
1060 			    pdev->si_name, physpath, pdev->si_name);
1061 		ret = ENAMETOOLONG;
1062 		goto out;
1063 	}
1064 
1065 	mflags = (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK;
1066 	devfspathbuf_len = physpath_len + /*/*/1 + parentpath_len + /*NUL*/1;
1067 	devfspath = malloc(devfspathbuf_len, M_DEVBUF, mflags);
1068 	if (devfspath == NULL) {
1069 		ret = ENOMEM;
1070 		goto out;
1071 	}
1072 
1073 	sprintf(devfspath, "%s/%s", physpath, pdev->si_name);
1074 	if (old_alias != NULL && strcmp(old_alias->si_name, devfspath) == 0) {
1075 		/* Retain the existing alias. */
1076 		*cdev = old_alias;
1077 		old_alias = NULL;
1078 		ret = 0;
1079 	} else {
1080 		ret = make_dev_alias_p(flags, cdev, pdev, "%s", devfspath);
1081 	}
1082 out:
1083 	if (old_alias != NULL)
1084 		destroy_dev(old_alias);
1085 	if (devfspath != NULL)
1086 		free(devfspath, M_DEVBUF);
1087 	return (ret);
1088 }
1089 
1090 static void
1091 destroy_devl(struct cdev *dev)
1092 {
1093 	struct cdevsw *csw;
1094 	struct cdev_privdata *p;
1095 	struct cdev_priv *cdp;
1096 
1097 	mtx_assert(&devmtx, MA_OWNED);
1098 	KASSERT(dev->si_flags & SI_NAMED,
1099 	    ("WARNING: Driver mistake: destroy_dev on %d\n", dev2unit(dev)));
1100 	KASSERT((dev->si_flags & SI_ETERNAL) == 0,
1101 	    ("WARNING: Driver mistake: destroy_dev on eternal %d\n",
1102 	     dev2unit(dev)));
1103 
1104 	cdp = cdev2priv(dev);
1105 	if ((cdp->cdp_flags & CDP_UNREF_DTR) == 0) {
1106 		/*
1107 		 * Avoid race with dev_rel(), e.g. from the populate
1108 		 * loop.  If CDP_UNREF_DTR flag is set, the reference
1109 		 * to be dropped at the end of destroy_devl() was
1110 		 * already taken by delist_dev_locked().
1111 		 */
1112 		dev_refl(dev);
1113 
1114 		devfs_destroy(dev);
1115 	}
1116 
1117 	/* Remove name marking */
1118 	dev->si_flags &= ~SI_NAMED;
1119 
1120 	/* If we are a child, remove us from the parents list */
1121 	if (dev->si_flags & SI_CHILD) {
1122 		LIST_REMOVE(dev, si_siblings);
1123 		dev->si_flags &= ~SI_CHILD;
1124 	}
1125 
1126 	/* Kill our children */
1127 	while (!LIST_EMPTY(&dev->si_children))
1128 		destroy_devl(LIST_FIRST(&dev->si_children));
1129 
1130 	/* Remove from clone list */
1131 	if (dev->si_flags & SI_CLONELIST) {
1132 		LIST_REMOVE(dev, si_clone);
1133 		dev->si_flags &= ~SI_CLONELIST;
1134 	}
1135 
1136 	csw = dev->si_devsw;
1137 	dev->si_devsw = NULL;	/* already NULL for SI_ALIAS */
1138 	while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
1139 		csw->d_purge(dev);
1140 		msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
1141 		if (dev->si_threadcount)
1142 			printf("Still %lu threads in %s\n",
1143 			    dev->si_threadcount, devtoname(dev));
1144 	}
1145 	while (dev->si_threadcount != 0) {
1146 		/* Use unique dummy wait ident */
1147 		msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10);
1148 	}
1149 
1150 	dev_unlock();
1151 	if ((cdp->cdp_flags & CDP_UNREF_DTR) == 0) {
1152 		/* avoid out of order notify events */
1153 		notify_destroy(dev);
1154 	}
1155 	mtx_lock(&cdevpriv_mtx);
1156 	while ((p = LIST_FIRST(&cdp->cdp_fdpriv)) != NULL) {
1157 		devfs_destroy_cdevpriv(p);
1158 		mtx_lock(&cdevpriv_mtx);
1159 	}
1160 	mtx_unlock(&cdevpriv_mtx);
1161 	dev_lock();
1162 
1163 	dev->si_drv1 = 0;
1164 	dev->si_drv2 = 0;
1165 	bzero(&dev->__si_u, sizeof(dev->__si_u));
1166 
1167 	if (!(dev->si_flags & SI_ALIAS)) {
1168 		/* Remove from cdevsw list */
1169 		LIST_REMOVE(dev, si_list);
1170 
1171 		/* If cdevsw has no more struct cdev *'s, clean it */
1172 		if (LIST_EMPTY(&csw->d_devs)) {
1173 			fini_cdevsw(csw);
1174 			wakeup(&csw->d_devs);
1175 		}
1176 	}
1177 	dev->si_flags &= ~SI_ALIAS;
1178 	cdp->cdp_flags &= ~CDP_UNREF_DTR;
1179 	dev->si_refcount--;
1180 
1181 	if (dev->si_refcount > 0)
1182 		LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
1183 	else
1184 		dev_free_devlocked(dev);
1185 }
1186 
1187 static void
1188 delist_dev_locked(struct cdev *dev)
1189 {
1190 	struct cdev_priv *cdp;
1191 	struct cdev *child;
1192 
1193 	mtx_assert(&devmtx, MA_OWNED);
1194 	cdp = cdev2priv(dev);
1195 	if ((cdp->cdp_flags & CDP_UNREF_DTR) != 0)
1196 		return;
1197 	cdp->cdp_flags |= CDP_UNREF_DTR;
1198 	dev_refl(dev);
1199 	devfs_destroy(dev);
1200 	LIST_FOREACH(child, &dev->si_children, si_siblings)
1201 		delist_dev_locked(child);
1202 	dev_unlock();
1203 	/* ensure the destroy event is queued in order */
1204 	notify_destroy(dev);
1205 	dev_lock();
1206 }
1207 
1208 /*
1209  * This function will delist a character device and its children from
1210  * the directory listing and create a destroy event without waiting
1211  * for all character device references to go away. At some later point
1212  * destroy_dev() must be called to complete the character device
1213  * destruction. After calling this function the character device name
1214  * can instantly be re-used.
1215  */
1216 void
1217 delist_dev(struct cdev *dev)
1218 {
1219 
1220 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "delist_dev");
1221 	dev_lock();
1222 	delist_dev_locked(dev);
1223 	dev_unlock();
1224 }
1225 
1226 void
1227 destroy_dev(struct cdev *dev)
1228 {
1229 
1230 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "destroy_dev");
1231 	dev_lock();
1232 	destroy_devl(dev);
1233 	dev_unlock_and_free();
1234 }
1235 
1236 const char *
1237 devtoname(struct cdev *dev)
1238 {
1239 
1240 	return (dev->si_name);
1241 }
1242 
1243 int
1244 dev_stdclone(char *name, char **namep, const char *stem, int *unit)
1245 {
1246 	int u, i;
1247 
1248 	i = strlen(stem);
1249 	if (bcmp(stem, name, i) != 0)
1250 		return (0);
1251 	if (!isdigit(name[i]))
1252 		return (0);
1253 	u = 0;
1254 	if (name[i] == '0' && isdigit(name[i+1]))
1255 		return (0);
1256 	while (isdigit(name[i])) {
1257 		u *= 10;
1258 		u += name[i++] - '0';
1259 	}
1260 	if (u > 0xffffff)
1261 		return (0);
1262 	*unit = u;
1263 	if (namep)
1264 		*namep = &name[i];
1265 	if (name[i])
1266 		return (2);
1267 	return (1);
1268 }
1269 
1270 /*
1271  * Helper functions for cloning device drivers.
1272  *
1273  * The objective here is to make it unnecessary for the device drivers to
1274  * use rman or similar to manage their unit number space.  Due to the way
1275  * we do "on-demand" devices, using rman or other "private" methods
1276  * will be very tricky to lock down properly once we lock down this file.
1277  *
1278  * Instead we give the drivers these routines which puts the struct cdev *'s
1279  * that are to be managed on their own list, and gives the driver the ability
1280  * to ask for the first free unit number or a given specified unit number.
1281  *
1282  * In addition these routines support paired devices (pty, nmdm and similar)
1283  * by respecting a number of "flag" bits in the minor number.
1284  *
1285  */
1286 
1287 struct clonedevs {
1288 	LIST_HEAD(,cdev)	head;
1289 };
1290 
1291 void
1292 clone_setup(struct clonedevs **cdp)
1293 {
1294 
1295 	*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
1296 	LIST_INIT(&(*cdp)->head);
1297 }
1298 
1299 int
1300 clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up,
1301     struct cdev **dp, int extra)
1302 {
1303 	struct clonedevs *cd;
1304 	struct cdev *dev, *ndev, *dl, *de;
1305 	struct make_dev_args args;
1306 	int unit, low, u;
1307 
1308 	KASSERT(*cdp != NULL,
1309 	    ("clone_setup() not called in driver \"%s\"", csw->d_name));
1310 	KASSERT(!(extra & CLONE_UNITMASK),
1311 	    ("Illegal extra bits (0x%x) in clone_create", extra));
1312 	KASSERT(*up <= CLONE_UNITMASK,
1313 	    ("Too high unit (0x%x) in clone_create", *up));
1314 	KASSERT(csw->d_flags & D_NEEDMINOR,
1315 	    ("clone_create() on cdevsw without minor numbers"));
1316 
1317 
1318 	/*
1319 	 * Search the list for a lot of things in one go:
1320 	 *   A preexisting match is returned immediately.
1321 	 *   The lowest free unit number if we are passed -1, and the place
1322 	 *	 in the list where we should insert that new element.
1323 	 *   The place to insert a specified unit number, if applicable
1324 	 *       the end of the list.
1325 	 */
1326 	unit = *up;
1327 	ndev = devfs_alloc(MAKEDEV_WAITOK);
1328 	dev_lock();
1329 	prep_cdevsw(csw, MAKEDEV_WAITOK);
1330 	low = extra;
1331 	de = dl = NULL;
1332 	cd = *cdp;
1333 	LIST_FOREACH(dev, &cd->head, si_clone) {
1334 		KASSERT(dev->si_flags & SI_CLONELIST,
1335 		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
1336 		u = dev2unit(dev);
1337 		if (u == (unit | extra)) {
1338 			*dp = dev;
1339 			dev_unlock();
1340 			devfs_free(ndev);
1341 			return (0);
1342 		}
1343 		if (unit == -1 && u == low) {
1344 			low++;
1345 			de = dev;
1346 			continue;
1347 		} else if (u < (unit | extra)) {
1348 			de = dev;
1349 			continue;
1350 		} else if (u > (unit | extra)) {
1351 			dl = dev;
1352 			break;
1353 		}
1354 	}
1355 	if (unit == -1)
1356 		unit = low & CLONE_UNITMASK;
1357 	make_dev_args_init(&args);
1358 	args.mda_unit = unit | extra;
1359 	args.mda_devsw = csw;
1360 	dev = newdev(&args, ndev);
1361 	if (dev->si_flags & SI_CLONELIST) {
1362 		printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
1363 		printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra);
1364 		LIST_FOREACH(dev, &cd->head, si_clone) {
1365 			printf("\t%p %s\n", dev, dev->si_name);
1366 		}
1367 		panic("foo");
1368 	}
1369 	KASSERT(!(dev->si_flags & SI_CLONELIST),
1370 	    ("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
1371 	if (dl != NULL)
1372 		LIST_INSERT_BEFORE(dl, dev, si_clone);
1373 	else if (de != NULL)
1374 		LIST_INSERT_AFTER(de, dev, si_clone);
1375 	else
1376 		LIST_INSERT_HEAD(&cd->head, dev, si_clone);
1377 	dev->si_flags |= SI_CLONELIST;
1378 	*up = unit;
1379 	dev_unlock_and_free();
1380 	return (1);
1381 }
1382 
1383 /*
1384  * Kill everything still on the list.  The driver should already have
1385  * disposed of any softc hung of the struct cdev *'s at this time.
1386  */
1387 void
1388 clone_cleanup(struct clonedevs **cdp)
1389 {
1390 	struct cdev *dev;
1391 	struct cdev_priv *cp;
1392 	struct clonedevs *cd;
1393 
1394 	cd = *cdp;
1395 	if (cd == NULL)
1396 		return;
1397 	dev_lock();
1398 	while (!LIST_EMPTY(&cd->head)) {
1399 		dev = LIST_FIRST(&cd->head);
1400 		LIST_REMOVE(dev, si_clone);
1401 		KASSERT(dev->si_flags & SI_CLONELIST,
1402 		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
1403 		dev->si_flags &= ~SI_CLONELIST;
1404 		cp = cdev2priv(dev);
1405 		if (!(cp->cdp_flags & CDP_SCHED_DTR)) {
1406 			cp->cdp_flags |= CDP_SCHED_DTR;
1407 			KASSERT(dev->si_flags & SI_NAMED,
1408 				("Driver has goofed in cloning underways udev %jx unit %x",
1409 				(uintmax_t)dev2udev(dev), dev2unit(dev)));
1410 			destroy_devl(dev);
1411 		}
1412 	}
1413 	dev_unlock_and_free();
1414 	free(cd, M_DEVBUF);
1415 	*cdp = NULL;
1416 }
1417 
1418 static TAILQ_HEAD(, cdev_priv) dev_ddtr =
1419 	TAILQ_HEAD_INITIALIZER(dev_ddtr);
1420 static struct task dev_dtr_task = TASK_INITIALIZER(0, destroy_dev_tq, NULL);
1421 
1422 static void
1423 destroy_dev_tq(void *ctx, int pending)
1424 {
1425 	struct cdev_priv *cp;
1426 	struct cdev *dev;
1427 	void (*cb)(void *);
1428 	void *cb_arg;
1429 
1430 	dev_lock();
1431 	while (!TAILQ_EMPTY(&dev_ddtr)) {
1432 		cp = TAILQ_FIRST(&dev_ddtr);
1433 		dev = &cp->cdp_c;
1434 		KASSERT(cp->cdp_flags & CDP_SCHED_DTR,
1435 		    ("cdev %p in dev_destroy_tq without CDP_SCHED_DTR", cp));
1436 		TAILQ_REMOVE(&dev_ddtr, cp, cdp_dtr_list);
1437 		cb = cp->cdp_dtr_cb;
1438 		cb_arg = cp->cdp_dtr_cb_arg;
1439 		destroy_devl(dev);
1440 		dev_unlock_and_free();
1441 		dev_rel(dev);
1442 		if (cb != NULL)
1443 			cb(cb_arg);
1444 		dev_lock();
1445 	}
1446 	dev_unlock();
1447 }
1448 
1449 /*
1450  * devmtx shall be locked on entry. devmtx will be unlocked after
1451  * function return.
1452  */
1453 static int
1454 destroy_dev_sched_cbl(struct cdev *dev, void (*cb)(void *), void *arg)
1455 {
1456 	struct cdev_priv *cp;
1457 
1458 	mtx_assert(&devmtx, MA_OWNED);
1459 	cp = cdev2priv(dev);
1460 	if (cp->cdp_flags & CDP_SCHED_DTR) {
1461 		dev_unlock();
1462 		return (0);
1463 	}
1464 	dev_refl(dev);
1465 	cp->cdp_flags |= CDP_SCHED_DTR;
1466 	cp->cdp_dtr_cb = cb;
1467 	cp->cdp_dtr_cb_arg = arg;
1468 	TAILQ_INSERT_TAIL(&dev_ddtr, cp, cdp_dtr_list);
1469 	dev_unlock();
1470 	taskqueue_enqueue(taskqueue_swi_giant, &dev_dtr_task);
1471 	return (1);
1472 }
1473 
1474 int
1475 destroy_dev_sched_cb(struct cdev *dev, void (*cb)(void *), void *arg)
1476 {
1477 
1478 	dev_lock();
1479 	return (destroy_dev_sched_cbl(dev, cb, arg));
1480 }
1481 
1482 int
1483 destroy_dev_sched(struct cdev *dev)
1484 {
1485 
1486 	return (destroy_dev_sched_cb(dev, NULL, NULL));
1487 }
1488 
1489 void
1490 destroy_dev_drain(struct cdevsw *csw)
1491 {
1492 
1493 	dev_lock();
1494 	while (!LIST_EMPTY(&csw->d_devs)) {
1495 		msleep(&csw->d_devs, &devmtx, PRIBIO, "devscd", hz/10);
1496 	}
1497 	dev_unlock();
1498 }
1499 
1500 void
1501 drain_dev_clone_events(void)
1502 {
1503 
1504 	sx_xlock(&clone_drain_lock);
1505 	sx_xunlock(&clone_drain_lock);
1506 }
1507 
1508 #include "opt_ddb.h"
1509 #ifdef DDB
1510 #include <sys/kernel.h>
1511 
1512 #include <ddb/ddb.h>
1513 
1514 DB_SHOW_COMMAND(cdev, db_show_cdev)
1515 {
1516 	struct cdev_priv *cdp;
1517 	struct cdev *dev;
1518 	u_int flags;
1519 	char buf[512];
1520 
1521 	if (!have_addr) {
1522 		TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
1523 			dev = &cdp->cdp_c;
1524 			db_printf("%s %p\n", dev->si_name, dev);
1525 			if (db_pager_quit)
1526 				break;
1527 		}
1528 		return;
1529 	}
1530 
1531 	dev = (struct cdev *)addr;
1532 	cdp = cdev2priv(dev);
1533 	db_printf("dev %s ref %d use %ld thr %ld inuse %u fdpriv %p\n",
1534 	    dev->si_name, dev->si_refcount, dev->si_usecount,
1535 	    dev->si_threadcount, cdp->cdp_inuse, cdp->cdp_fdpriv.lh_first);
1536 	db_printf("devsw %p si_drv0 %d si_drv1 %p si_drv2 %p\n",
1537 	    dev->si_devsw, dev->si_drv0, dev->si_drv1, dev->si_drv2);
1538 	flags = dev->si_flags;
1539 #define	SI_FLAG(flag)	do {						\
1540 	if (flags & (flag)) {						\
1541 		if (buf[0] != '\0')					\
1542 			strlcat(buf, ", ", sizeof(buf));		\
1543 		strlcat(buf, (#flag) + 3, sizeof(buf));			\
1544 		flags &= ~(flag);					\
1545 	}								\
1546 } while (0)
1547 	buf[0] = '\0';
1548 	SI_FLAG(SI_ETERNAL);
1549 	SI_FLAG(SI_ALIAS);
1550 	SI_FLAG(SI_NAMED);
1551 	SI_FLAG(SI_CHILD);
1552 	SI_FLAG(SI_DUMPDEV);
1553 	SI_FLAG(SI_CLONELIST);
1554 	db_printf("si_flags %s\n", buf);
1555 
1556 	flags = cdp->cdp_flags;
1557 #define	CDP_FLAG(flag)	do {						\
1558 	if (flags & (flag)) {						\
1559 		if (buf[0] != '\0')					\
1560 			strlcat(buf, ", ", sizeof(buf));		\
1561 		strlcat(buf, (#flag) + 4, sizeof(buf));			\
1562 		flags &= ~(flag);					\
1563 	}								\
1564 } while (0)
1565 	buf[0] = '\0';
1566 	CDP_FLAG(CDP_ACTIVE);
1567 	CDP_FLAG(CDP_SCHED_DTR);
1568 	db_printf("cdp_flags %s\n", buf);
1569 }
1570 #endif
1571