xref: /freebsd/sys/kern/kern_conf.c (revision eb69d1f144a6fcc765d1b9d44a5ae8082353e70b)
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 0
170 	if (dev->si_usecount == 0 &&
171 	    (dev->si_flags & SI_CHEAPCLONE) && (dev->si_flags & SI_NAMED))
172 		;
173 	else
174 #endif
175 	if (dev->si_devsw == NULL && dev->si_refcount == 0) {
176 		LIST_REMOVE(dev, si_list);
177 		flag = 1;
178 	}
179 	dev_unlock();
180 	if (flag)
181 		devfs_free(dev);
182 }
183 
184 struct cdevsw *
185 dev_refthread(struct cdev *dev, int *ref)
186 {
187 	struct cdevsw *csw;
188 	struct cdev_priv *cdp;
189 
190 	mtx_assert(&devmtx, MA_NOTOWNED);
191 	if ((dev->si_flags & SI_ETERNAL) != 0) {
192 		*ref = 0;
193 		return (dev->si_devsw);
194 	}
195 	dev_lock();
196 	csw = dev->si_devsw;
197 	if (csw != NULL) {
198 		cdp = cdev2priv(dev);
199 		if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0)
200 			atomic_add_long(&dev->si_threadcount, 1);
201 		else
202 			csw = NULL;
203 	}
204 	dev_unlock();
205 	*ref = 1;
206 	return (csw);
207 }
208 
209 struct cdevsw *
210 devvn_refthread(struct vnode *vp, struct cdev **devp, int *ref)
211 {
212 	struct cdevsw *csw;
213 	struct cdev_priv *cdp;
214 	struct cdev *dev;
215 
216 	mtx_assert(&devmtx, MA_NOTOWNED);
217 	if ((vp->v_vflag & VV_ETERNALDEV) != 0) {
218 		dev = vp->v_rdev;
219 		if (dev == NULL)
220 			return (NULL);
221 		KASSERT((dev->si_flags & SI_ETERNAL) != 0,
222 		    ("Not eternal cdev"));
223 		*ref = 0;
224 		csw = dev->si_devsw;
225 		KASSERT(csw != NULL, ("Eternal cdev is destroyed"));
226 		*devp = dev;
227 		return (csw);
228 	}
229 
230 	csw = NULL;
231 	dev_lock();
232 	dev = vp->v_rdev;
233 	if (dev == NULL) {
234 		dev_unlock();
235 		return (NULL);
236 	}
237 	cdp = cdev2priv(dev);
238 	if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0) {
239 		csw = dev->si_devsw;
240 		if (csw != NULL)
241 			atomic_add_long(&dev->si_threadcount, 1);
242 	}
243 	dev_unlock();
244 	if (csw != NULL) {
245 		*devp = dev;
246 		*ref = 1;
247 	}
248 	return (csw);
249 }
250 
251 void
252 dev_relthread(struct cdev *dev, int ref)
253 {
254 
255 	mtx_assert(&devmtx, MA_NOTOWNED);
256 	if (!ref)
257 		return;
258 	KASSERT(dev->si_threadcount > 0,
259 	    ("%s threadcount is wrong", dev->si_name));
260 	atomic_subtract_rel_long(&dev->si_threadcount, 1);
261 }
262 
263 int
264 nullop(void)
265 {
266 
267 	return (0);
268 }
269 
270 int
271 eopnotsupp(void)
272 {
273 
274 	return (EOPNOTSUPP);
275 }
276 
277 static int
278 enxio(void)
279 {
280 	return (ENXIO);
281 }
282 
283 static int
284 enodev(void)
285 {
286 	return (ENODEV);
287 }
288 
289 /* Define a dead_cdevsw for use when devices leave unexpectedly. */
290 
291 #define dead_open	(d_open_t *)enxio
292 #define dead_close	(d_close_t *)enxio
293 #define dead_read	(d_read_t *)enxio
294 #define dead_write	(d_write_t *)enxio
295 #define dead_ioctl	(d_ioctl_t *)enxio
296 #define dead_poll	(d_poll_t *)enodev
297 #define dead_mmap	(d_mmap_t *)enodev
298 
299 static void
300 dead_strategy(struct bio *bp)
301 {
302 
303 	biofinish(bp, NULL, ENXIO);
304 }
305 
306 #define dead_dump	(dumper_t *)enxio
307 #define dead_kqfilter	(d_kqfilter_t *)enxio
308 #define dead_mmap_single (d_mmap_single_t *)enodev
309 
310 static struct cdevsw dead_cdevsw = {
311 	.d_version =	D_VERSION,
312 	.d_open =	dead_open,
313 	.d_close =	dead_close,
314 	.d_read =	dead_read,
315 	.d_write =	dead_write,
316 	.d_ioctl =	dead_ioctl,
317 	.d_poll =	dead_poll,
318 	.d_mmap =	dead_mmap,
319 	.d_strategy =	dead_strategy,
320 	.d_name =	"dead",
321 	.d_dump =	dead_dump,
322 	.d_kqfilter =	dead_kqfilter,
323 	.d_mmap_single = dead_mmap_single
324 };
325 
326 /* Default methods if driver does not specify method */
327 
328 #define null_open	(d_open_t *)nullop
329 #define null_close	(d_close_t *)nullop
330 #define no_read		(d_read_t *)enodev
331 #define no_write	(d_write_t *)enodev
332 #define no_ioctl	(d_ioctl_t *)enodev
333 #define no_mmap		(d_mmap_t *)enodev
334 #define no_kqfilter	(d_kqfilter_t *)enodev
335 #define no_mmap_single	(d_mmap_single_t *)enodev
336 
337 static void
338 no_strategy(struct bio *bp)
339 {
340 
341 	biofinish(bp, NULL, ENODEV);
342 }
343 
344 static int
345 no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
346 {
347 
348 	return (poll_no_poll(events));
349 }
350 
351 #define no_dump		(dumper_t *)enodev
352 
353 static int
354 giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
355 {
356 	struct cdevsw *dsw;
357 	int ref, retval;
358 
359 	dsw = dev_refthread(dev, &ref);
360 	if (dsw == NULL)
361 		return (ENXIO);
362 	mtx_lock(&Giant);
363 	retval = dsw->d_gianttrick->d_open(dev, oflags, devtype, td);
364 	mtx_unlock(&Giant);
365 	dev_relthread(dev, ref);
366 	return (retval);
367 }
368 
369 static int
370 giant_fdopen(struct cdev *dev, int oflags, struct thread *td, struct file *fp)
371 {
372 	struct cdevsw *dsw;
373 	int ref, retval;
374 
375 	dsw = dev_refthread(dev, &ref);
376 	if (dsw == NULL)
377 		return (ENXIO);
378 	mtx_lock(&Giant);
379 	retval = dsw->d_gianttrick->d_fdopen(dev, oflags, td, fp);
380 	mtx_unlock(&Giant);
381 	dev_relthread(dev, ref);
382 	return (retval);
383 }
384 
385 static int
386 giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
387 {
388 	struct cdevsw *dsw;
389 	int ref, retval;
390 
391 	dsw = dev_refthread(dev, &ref);
392 	if (dsw == NULL)
393 		return (ENXIO);
394 	mtx_lock(&Giant);
395 	retval = dsw->d_gianttrick->d_close(dev, fflag, devtype, td);
396 	mtx_unlock(&Giant);
397 	dev_relthread(dev, ref);
398 	return (retval);
399 }
400 
401 static void
402 giant_strategy(struct bio *bp)
403 {
404 	struct cdevsw *dsw;
405 	struct cdev *dev;
406 	int ref;
407 
408 	dev = bp->bio_dev;
409 	dsw = dev_refthread(dev, &ref);
410 	if (dsw == NULL) {
411 		biofinish(bp, NULL, ENXIO);
412 		return;
413 	}
414 	mtx_lock(&Giant);
415 	dsw->d_gianttrick->d_strategy(bp);
416 	mtx_unlock(&Giant);
417 	dev_relthread(dev, ref);
418 }
419 
420 static int
421 giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
422 {
423 	struct cdevsw *dsw;
424 	int ref, retval;
425 
426 	dsw = dev_refthread(dev, &ref);
427 	if (dsw == NULL)
428 		return (ENXIO);
429 	mtx_lock(&Giant);
430 	retval = dsw->d_gianttrick->d_ioctl(dev, cmd, data, fflag, td);
431 	mtx_unlock(&Giant);
432 	dev_relthread(dev, ref);
433 	return (retval);
434 }
435 
436 static int
437 giant_read(struct cdev *dev, struct uio *uio, int ioflag)
438 {
439 	struct cdevsw *dsw;
440 	int ref, retval;
441 
442 	dsw = dev_refthread(dev, &ref);
443 	if (dsw == NULL)
444 		return (ENXIO);
445 	mtx_lock(&Giant);
446 	retval = dsw->d_gianttrick->d_read(dev, uio, ioflag);
447 	mtx_unlock(&Giant);
448 	dev_relthread(dev, ref);
449 	return (retval);
450 }
451 
452 static int
453 giant_write(struct cdev *dev, struct uio *uio, int ioflag)
454 {
455 	struct cdevsw *dsw;
456 	int ref, retval;
457 
458 	dsw = dev_refthread(dev, &ref);
459 	if (dsw == NULL)
460 		return (ENXIO);
461 	mtx_lock(&Giant);
462 	retval = dsw->d_gianttrick->d_write(dev, uio, ioflag);
463 	mtx_unlock(&Giant);
464 	dev_relthread(dev, ref);
465 	return (retval);
466 }
467 
468 static int
469 giant_poll(struct cdev *dev, int events, struct thread *td)
470 {
471 	struct cdevsw *dsw;
472 	int ref, retval;
473 
474 	dsw = dev_refthread(dev, &ref);
475 	if (dsw == NULL)
476 		return (ENXIO);
477 	mtx_lock(&Giant);
478 	retval = dsw->d_gianttrick->d_poll(dev, events, td);
479 	mtx_unlock(&Giant);
480 	dev_relthread(dev, ref);
481 	return (retval);
482 }
483 
484 static int
485 giant_kqfilter(struct cdev *dev, struct knote *kn)
486 {
487 	struct cdevsw *dsw;
488 	int ref, retval;
489 
490 	dsw = dev_refthread(dev, &ref);
491 	if (dsw == NULL)
492 		return (ENXIO);
493 	mtx_lock(&Giant);
494 	retval = dsw->d_gianttrick->d_kqfilter(dev, kn);
495 	mtx_unlock(&Giant);
496 	dev_relthread(dev, ref);
497 	return (retval);
498 }
499 
500 static int
501 giant_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, int nprot,
502     vm_memattr_t *memattr)
503 {
504 	struct cdevsw *dsw;
505 	int ref, retval;
506 
507 	dsw = dev_refthread(dev, &ref);
508 	if (dsw == NULL)
509 		return (ENXIO);
510 	mtx_lock(&Giant);
511 	retval = dsw->d_gianttrick->d_mmap(dev, offset, paddr, nprot,
512 	    memattr);
513 	mtx_unlock(&Giant);
514 	dev_relthread(dev, ref);
515 	return (retval);
516 }
517 
518 static int
519 giant_mmap_single(struct cdev *dev, vm_ooffset_t *offset, vm_size_t size,
520     vm_object_t *object, int nprot)
521 {
522 	struct cdevsw *dsw;
523 	int ref, retval;
524 
525 	dsw = dev_refthread(dev, &ref);
526 	if (dsw == NULL)
527 		return (ENXIO);
528 	mtx_lock(&Giant);
529 	retval = dsw->d_gianttrick->d_mmap_single(dev, offset, size, object,
530 	    nprot);
531 	mtx_unlock(&Giant);
532 	dev_relthread(dev, ref);
533 	return (retval);
534 }
535 
536 static void
537 notify(struct cdev *dev, const char *ev, int flags)
538 {
539 	static const char prefix[] = "cdev=";
540 	char *data;
541 	int namelen, mflags;
542 
543 	if (cold)
544 		return;
545 	mflags = (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK;
546 	namelen = strlen(dev->si_name);
547 	data = malloc(namelen + sizeof(prefix), M_TEMP, mflags);
548 	if (data == NULL)
549 		return;
550 	memcpy(data, prefix, sizeof(prefix) - 1);
551 	memcpy(data + sizeof(prefix) - 1, dev->si_name, namelen + 1);
552 	devctl_notify_f("DEVFS", "CDEV", ev, data, mflags);
553 	free(data, M_TEMP);
554 }
555 
556 static void
557 notify_create(struct cdev *dev, int flags)
558 {
559 
560 	notify(dev, "CREATE", flags);
561 }
562 
563 static void
564 notify_destroy(struct cdev *dev)
565 {
566 
567 	notify(dev, "DESTROY", MAKEDEV_WAITOK);
568 }
569 
570 static struct cdev *
571 newdev(struct make_dev_args *args, struct cdev *si)
572 {
573 	struct cdev *si2;
574 	struct cdevsw *csw;
575 
576 	mtx_assert(&devmtx, MA_OWNED);
577 	csw = args->mda_devsw;
578 	if (csw->d_flags & D_NEEDMINOR) {
579 		/* We may want to return an existing device */
580 		LIST_FOREACH(si2, &csw->d_devs, si_list) {
581 			if (dev2unit(si2) == args->mda_unit) {
582 				dev_free_devlocked(si);
583 				return (si2);
584 			}
585 		}
586 	}
587 	si->si_drv0 = args->mda_unit;
588 	si->si_devsw = csw;
589 	si->si_drv1 = args->mda_si_drv1;
590 	si->si_drv2 = args->mda_si_drv2;
591 	LIST_INSERT_HEAD(&csw->d_devs, si, si_list);
592 	return (si);
593 }
594 
595 static void
596 fini_cdevsw(struct cdevsw *devsw)
597 {
598 	struct cdevsw *gt;
599 
600 	if (devsw->d_gianttrick != NULL) {
601 		gt = devsw->d_gianttrick;
602 		memcpy(devsw, gt, sizeof *devsw);
603 		cdevsw_free_devlocked(gt);
604 		devsw->d_gianttrick = NULL;
605 	}
606 	devsw->d_flags &= ~D_INIT;
607 }
608 
609 static int
610 prep_cdevsw(struct cdevsw *devsw, int flags)
611 {
612 	struct cdevsw *dsw2;
613 
614 	mtx_assert(&devmtx, MA_OWNED);
615 	if (devsw->d_flags & D_INIT)
616 		return (0);
617 	if (devsw->d_flags & D_NEEDGIANT) {
618 		dev_unlock();
619 		dsw2 = malloc(sizeof *dsw2, M_DEVT,
620 		     (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK);
621 		dev_lock();
622 		if (dsw2 == NULL && !(devsw->d_flags & D_INIT))
623 			return (ENOMEM);
624 	} else
625 		dsw2 = NULL;
626 	if (devsw->d_flags & D_INIT) {
627 		if (dsw2 != NULL)
628 			cdevsw_free_devlocked(dsw2);
629 		return (0);
630 	}
631 
632 	if (devsw->d_version != D_VERSION_03) {
633 		printf(
634 		    "WARNING: Device driver \"%s\" has wrong version %s\n",
635 		    devsw->d_name == NULL ? "???" : devsw->d_name,
636 		    "and is disabled.  Recompile KLD module.");
637 		devsw->d_open = dead_open;
638 		devsw->d_close = dead_close;
639 		devsw->d_read = dead_read;
640 		devsw->d_write = dead_write;
641 		devsw->d_ioctl = dead_ioctl;
642 		devsw->d_poll = dead_poll;
643 		devsw->d_mmap = dead_mmap;
644 		devsw->d_mmap_single = dead_mmap_single;
645 		devsw->d_strategy = dead_strategy;
646 		devsw->d_dump = dead_dump;
647 		devsw->d_kqfilter = dead_kqfilter;
648 	}
649 
650 	if (devsw->d_flags & D_NEEDGIANT) {
651 		if (devsw->d_gianttrick == NULL) {
652 			memcpy(dsw2, devsw, sizeof *dsw2);
653 			devsw->d_gianttrick = dsw2;
654 			dsw2 = NULL;
655 		}
656 	}
657 
658 #define FIXUP(member, noop, giant) 				\
659 	do {							\
660 		if (devsw->member == NULL) {			\
661 			devsw->member = noop;			\
662 		} else if (devsw->d_flags & D_NEEDGIANT)	\
663 			devsw->member = giant;			\
664 		}						\
665 	while (0)
666 
667 	FIXUP(d_open,		null_open,	giant_open);
668 	FIXUP(d_fdopen,		NULL,		giant_fdopen);
669 	FIXUP(d_close,		null_close,	giant_close);
670 	FIXUP(d_read,		no_read,	giant_read);
671 	FIXUP(d_write,		no_write,	giant_write);
672 	FIXUP(d_ioctl,		no_ioctl,	giant_ioctl);
673 	FIXUP(d_poll,		no_poll,	giant_poll);
674 	FIXUP(d_mmap,		no_mmap,	giant_mmap);
675 	FIXUP(d_strategy,	no_strategy,	giant_strategy);
676 	FIXUP(d_kqfilter,	no_kqfilter,	giant_kqfilter);
677 	FIXUP(d_mmap_single,	no_mmap_single,	giant_mmap_single);
678 
679 	if (devsw->d_dump == NULL)	devsw->d_dump = no_dump;
680 
681 	LIST_INIT(&devsw->d_devs);
682 
683 	devsw->d_flags |= D_INIT;
684 
685 	if (dsw2 != NULL)
686 		cdevsw_free_devlocked(dsw2);
687 	return (0);
688 }
689 
690 static int
691 prep_devname(struct cdev *dev, const char *fmt, va_list ap)
692 {
693 	int len;
694 	char *from, *q, *s, *to;
695 
696 	mtx_assert(&devmtx, MA_OWNED);
697 
698 	len = vsnrprintf(dev->si_name, sizeof(dev->si_name), 32, fmt, ap);
699 	if (len > sizeof(dev->si_name) - 1)
700 		return (ENAMETOOLONG);
701 
702 	/* Strip leading slashes. */
703 	for (from = dev->si_name; *from == '/'; from++)
704 		;
705 
706 	for (to = dev->si_name; *from != '\0'; from++, to++) {
707 		/*
708 		 * Spaces and double quotation marks cause
709 		 * problems for the devctl(4) protocol.
710 		 * Reject names containing those characters.
711 		 */
712 		if (isspace(*from) || *from == '"')
713 			return (EINVAL);
714 		/* Treat multiple sequential slashes as single. */
715 		while (from[0] == '/' && from[1] == '/')
716 			from++;
717 		/* Trailing slash is considered invalid. */
718 		if (from[0] == '/' && from[1] == '\0')
719 			return (EINVAL);
720 		*to = *from;
721 	}
722 	*to = '\0';
723 
724 	if (dev->si_name[0] == '\0')
725 		return (EINVAL);
726 
727 	/* Disallow "." and ".." components. */
728 	for (s = dev->si_name;;) {
729 		for (q = s; *q != '/' && *q != '\0'; q++)
730 			;
731 		if (q - s == 1 && s[0] == '.')
732 			return (EINVAL);
733 		if (q - s == 2 && s[0] == '.' && s[1] == '.')
734 			return (EINVAL);
735 		if (*q != '/')
736 			break;
737 		s = q + 1;
738 	}
739 
740 	if (devfs_dev_exists(dev->si_name) != 0)
741 		return (EEXIST);
742 
743 	return (0);
744 }
745 
746 void
747 make_dev_args_init_impl(struct make_dev_args *args, size_t sz)
748 {
749 
750 	bzero(args, sz);
751 	args->mda_size = sz;
752 }
753 
754 static int
755 make_dev_sv(struct make_dev_args *args1, struct cdev **dres,
756     const char *fmt, va_list ap)
757 {
758 	struct cdev *dev, *dev_new;
759 	struct make_dev_args args;
760 	int res;
761 
762 	bzero(&args, sizeof(args));
763 	if (sizeof(args) < args1->mda_size)
764 		return (EINVAL);
765 	bcopy(args1, &args, args1->mda_size);
766 	KASSERT((args.mda_flags & MAKEDEV_WAITOK) == 0 ||
767 	    (args.mda_flags & MAKEDEV_NOWAIT) == 0,
768 	    ("make_dev_sv: both WAITOK and NOWAIT specified"));
769 	dev_new = devfs_alloc(args.mda_flags);
770 	if (dev_new == NULL)
771 		return (ENOMEM);
772 	dev_lock();
773 	res = prep_cdevsw(args.mda_devsw, args.mda_flags);
774 	if (res != 0) {
775 		dev_unlock();
776 		devfs_free(dev_new);
777 		return (res);
778 	}
779 	dev = newdev(&args, dev_new);
780 	if ((dev->si_flags & SI_NAMED) == 0) {
781 		res = prep_devname(dev, fmt, ap);
782 		if (res != 0) {
783 			if ((args.mda_flags & MAKEDEV_CHECKNAME) == 0) {
784 				panic(
785 			"make_dev_sv: bad si_name (error=%d, si_name=%s)",
786 				    res, dev->si_name);
787 			}
788 			if (dev == dev_new) {
789 				LIST_REMOVE(dev, si_list);
790 				dev_unlock();
791 				devfs_free(dev);
792 			} else
793 				dev_unlock();
794 			return (res);
795 		}
796 	}
797 	if ((args.mda_flags & MAKEDEV_REF) != 0)
798 		dev_refl(dev);
799 	if ((args.mda_flags & MAKEDEV_ETERNAL) != 0)
800 		dev->si_flags |= SI_ETERNAL;
801 	if (dev->si_flags & SI_CHEAPCLONE &&
802 	    dev->si_flags & SI_NAMED) {
803 		/*
804 		 * This is allowed as it removes races and generally
805 		 * simplifies cloning devices.
806 		 * XXX: still ??
807 		 */
808 		dev_unlock_and_free();
809 		*dres = dev;
810 		return (0);
811 	}
812 	KASSERT(!(dev->si_flags & SI_NAMED),
813 	    ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
814 	    args.mda_devsw->d_name, dev2unit(dev), devtoname(dev)));
815 	dev->si_flags |= SI_NAMED;
816 	if (args.mda_cr != NULL)
817 		dev->si_cred = crhold(args.mda_cr);
818 	dev->si_uid = args.mda_uid;
819 	dev->si_gid = args.mda_gid;
820 	dev->si_mode = args.mda_mode;
821 
822 	devfs_create(dev);
823 	clean_unrhdrl(devfs_inos);
824 	dev_unlock_and_free();
825 
826 	notify_create(dev, args.mda_flags);
827 
828 	*dres = dev;
829 	return (0);
830 }
831 
832 int
833 make_dev_s(struct make_dev_args *args, struct cdev **dres,
834     const char *fmt, ...)
835 {
836 	va_list ap;
837 	int res;
838 
839 	va_start(ap, fmt);
840 	res = make_dev_sv(args, dres, fmt, ap);
841 	va_end(ap);
842 	return (res);
843 }
844 
845 static int
846 make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw, int unit,
847     struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
848     va_list ap)
849 {
850 	struct make_dev_args args;
851 
852 	make_dev_args_init(&args);
853 	args.mda_flags = flags;
854 	args.mda_devsw = devsw;
855 	args.mda_cr = cr;
856 	args.mda_uid = uid;
857 	args.mda_gid = gid;
858 	args.mda_mode = mode;
859 	args.mda_unit = unit;
860 	return (make_dev_sv(&args, dres, fmt, ap));
861 }
862 
863 struct cdev *
864 make_dev(struct cdevsw *devsw, int unit, uid_t uid, gid_t gid, int mode,
865     const char *fmt, ...)
866 {
867 	struct cdev *dev;
868 	va_list ap;
869 	int res;
870 
871 	va_start(ap, fmt);
872 	res = make_dev_credv(0, &dev, devsw, unit, NULL, uid, gid, mode, fmt,
873 	    ap);
874 	va_end(ap);
875 	KASSERT(res == 0 && dev != NULL,
876 	    ("make_dev: failed make_dev_credv (error=%d)", res));
877 	return (dev);
878 }
879 
880 struct cdev *
881 make_dev_cred(struct cdevsw *devsw, int unit, struct ucred *cr, uid_t uid,
882     gid_t gid, int mode, const char *fmt, ...)
883 {
884 	struct cdev *dev;
885 	va_list ap;
886 	int res;
887 
888 	va_start(ap, fmt);
889 	res = make_dev_credv(0, &dev, devsw, unit, cr, uid, gid, mode, fmt, ap);
890 	va_end(ap);
891 
892 	KASSERT(res == 0 && dev != NULL,
893 	    ("make_dev_cred: failed make_dev_credv (error=%d)", res));
894 	return (dev);
895 }
896 
897 struct cdev *
898 make_dev_credf(int flags, struct cdevsw *devsw, int unit, struct ucred *cr,
899     uid_t uid, gid_t gid, int mode, const char *fmt, ...)
900 {
901 	struct cdev *dev;
902 	va_list ap;
903 	int res;
904 
905 	va_start(ap, fmt);
906 	res = make_dev_credv(flags, &dev, devsw, unit, cr, uid, gid, mode,
907 	    fmt, ap);
908 	va_end(ap);
909 
910 	KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
911 	    ((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
912 	    ("make_dev_credf: failed make_dev_credv (error=%d)", res));
913 	return (res == 0 ? dev : NULL);
914 }
915 
916 int
917 make_dev_p(int flags, struct cdev **cdev, struct cdevsw *devsw,
918     struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt, ...)
919 {
920 	va_list ap;
921 	int res;
922 
923 	va_start(ap, fmt);
924 	res = make_dev_credv(flags, cdev, devsw, 0, cr, uid, gid, mode,
925 	    fmt, ap);
926 	va_end(ap);
927 
928 	KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
929 	    ((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
930 	    ("make_dev_p: failed make_dev_credv (error=%d)", res));
931 	return (res);
932 }
933 
934 static void
935 dev_dependsl(struct cdev *pdev, struct cdev *cdev)
936 {
937 
938 	cdev->si_parent = pdev;
939 	cdev->si_flags |= SI_CHILD;
940 	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
941 }
942 
943 
944 void
945 dev_depends(struct cdev *pdev, struct cdev *cdev)
946 {
947 
948 	dev_lock();
949 	dev_dependsl(pdev, cdev);
950 	dev_unlock();
951 }
952 
953 static int
954 make_dev_alias_v(int flags, struct cdev **cdev, struct cdev *pdev,
955     const char *fmt, va_list ap)
956 {
957 	struct cdev *dev;
958 	int error;
959 
960 	KASSERT(pdev != NULL, ("make_dev_alias_v: pdev is NULL"));
961 	KASSERT((flags & MAKEDEV_WAITOK) == 0 || (flags & MAKEDEV_NOWAIT) == 0,
962 	    ("make_dev_alias_v: both WAITOK and NOWAIT specified"));
963 	KASSERT((flags & ~(MAKEDEV_WAITOK | MAKEDEV_NOWAIT |
964 	    MAKEDEV_CHECKNAME)) == 0,
965 	    ("make_dev_alias_v: invalid flags specified (flags=%02x)", flags));
966 
967 	dev = devfs_alloc(flags);
968 	if (dev == NULL)
969 		return (ENOMEM);
970 	dev_lock();
971 	dev->si_flags |= SI_ALIAS;
972 	error = prep_devname(dev, fmt, ap);
973 	if (error != 0) {
974 		if ((flags & MAKEDEV_CHECKNAME) == 0) {
975 			panic("make_dev_alias_v: bad si_name "
976 			    "(error=%d, si_name=%s)", error, dev->si_name);
977 		}
978 		dev_unlock();
979 		devfs_free(dev);
980 		return (error);
981 	}
982 	dev->si_flags |= SI_NAMED;
983 	devfs_create(dev);
984 	dev_dependsl(pdev, dev);
985 	clean_unrhdrl(devfs_inos);
986 	dev_unlock();
987 
988 	notify_create(dev, flags);
989 	*cdev = dev;
990 
991 	return (0);
992 }
993 
994 struct cdev *
995 make_dev_alias(struct cdev *pdev, const char *fmt, ...)
996 {
997 	struct cdev *dev;
998 	va_list ap;
999 	int res;
1000 
1001 	va_start(ap, fmt);
1002 	res = make_dev_alias_v(MAKEDEV_WAITOK, &dev, pdev, fmt, ap);
1003 	va_end(ap);
1004 
1005 	KASSERT(res == 0 && dev != NULL,
1006 	    ("make_dev_alias: failed make_dev_alias_v (error=%d)", res));
1007 	return (dev);
1008 }
1009 
1010 int
1011 make_dev_alias_p(int flags, struct cdev **cdev, struct cdev *pdev,
1012     const char *fmt, ...)
1013 {
1014 	va_list ap;
1015 	int res;
1016 
1017 	va_start(ap, fmt);
1018 	res = make_dev_alias_v(flags, cdev, pdev, fmt, ap);
1019 	va_end(ap);
1020 	return (res);
1021 }
1022 
1023 int
1024 make_dev_physpath_alias(int flags, struct cdev **cdev, struct cdev *pdev,
1025     struct cdev *old_alias, const char *physpath)
1026 {
1027 	char *devfspath;
1028 	int physpath_len;
1029 	int max_parentpath_len;
1030 	int parentpath_len;
1031 	int devfspathbuf_len;
1032 	int mflags;
1033 	int ret;
1034 
1035 	*cdev = NULL;
1036 	devfspath = NULL;
1037 	physpath_len = strlen(physpath);
1038 	ret = EINVAL;
1039 	if (physpath_len == 0)
1040 		goto out;
1041 
1042 	if (strncmp("id1,", physpath, 4) == 0) {
1043 		physpath += 4;
1044 		physpath_len -= 4;
1045 		if (physpath_len == 0)
1046 			goto out;
1047 	}
1048 
1049 	max_parentpath_len = SPECNAMELEN - physpath_len - /*/*/1;
1050 	parentpath_len = strlen(pdev->si_name);
1051 	if (max_parentpath_len < parentpath_len) {
1052 		if (bootverbose)
1053 			printf("WARNING: Unable to alias %s "
1054 			    "to %s/%s - path too long\n",
1055 			    pdev->si_name, physpath, pdev->si_name);
1056 		ret = ENAMETOOLONG;
1057 		goto out;
1058 	}
1059 
1060 	mflags = (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK;
1061 	devfspathbuf_len = physpath_len + /*/*/1 + parentpath_len + /*NUL*/1;
1062 	devfspath = malloc(devfspathbuf_len, M_DEVBUF, mflags);
1063 	if (devfspath == NULL) {
1064 		ret = ENOMEM;
1065 		goto out;
1066 	}
1067 
1068 	sprintf(devfspath, "%s/%s", physpath, pdev->si_name);
1069 	if (old_alias != NULL && strcmp(old_alias->si_name, devfspath) == 0) {
1070 		/* Retain the existing alias. */
1071 		*cdev = old_alias;
1072 		old_alias = NULL;
1073 		ret = 0;
1074 	} else {
1075 		ret = make_dev_alias_p(flags, cdev, pdev, "%s", devfspath);
1076 	}
1077 out:
1078 	if (old_alias != NULL)
1079 		destroy_dev(old_alias);
1080 	if (devfspath != NULL)
1081 		free(devfspath, M_DEVBUF);
1082 	return (ret);
1083 }
1084 
1085 static void
1086 destroy_devl(struct cdev *dev)
1087 {
1088 	struct cdevsw *csw;
1089 	struct cdev_privdata *p;
1090 	struct cdev_priv *cdp;
1091 
1092 	mtx_assert(&devmtx, MA_OWNED);
1093 	KASSERT(dev->si_flags & SI_NAMED,
1094 	    ("WARNING: Driver mistake: destroy_dev on %d\n", dev2unit(dev)));
1095 	KASSERT((dev->si_flags & SI_ETERNAL) == 0,
1096 	    ("WARNING: Driver mistake: destroy_dev on eternal %d\n",
1097 	     dev2unit(dev)));
1098 
1099 	cdp = cdev2priv(dev);
1100 	if ((cdp->cdp_flags & CDP_UNREF_DTR) == 0) {
1101 		/*
1102 		 * Avoid race with dev_rel(), e.g. from the populate
1103 		 * loop.  If CDP_UNREF_DTR flag is set, the reference
1104 		 * to be dropped at the end of destroy_devl() was
1105 		 * already taken by delist_dev_locked().
1106 		 */
1107 		dev_refl(dev);
1108 
1109 		devfs_destroy(dev);
1110 	}
1111 
1112 	/* Remove name marking */
1113 	dev->si_flags &= ~SI_NAMED;
1114 
1115 	/* If we are a child, remove us from the parents list */
1116 	if (dev->si_flags & SI_CHILD) {
1117 		LIST_REMOVE(dev, si_siblings);
1118 		dev->si_flags &= ~SI_CHILD;
1119 	}
1120 
1121 	/* Kill our children */
1122 	while (!LIST_EMPTY(&dev->si_children))
1123 		destroy_devl(LIST_FIRST(&dev->si_children));
1124 
1125 	/* Remove from clone list */
1126 	if (dev->si_flags & SI_CLONELIST) {
1127 		LIST_REMOVE(dev, si_clone);
1128 		dev->si_flags &= ~SI_CLONELIST;
1129 	}
1130 
1131 	csw = dev->si_devsw;
1132 	dev->si_devsw = NULL;	/* already NULL for SI_ALIAS */
1133 	while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
1134 		csw->d_purge(dev);
1135 		msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
1136 		if (dev->si_threadcount)
1137 			printf("Still %lu threads in %s\n",
1138 			    dev->si_threadcount, devtoname(dev));
1139 	}
1140 	while (dev->si_threadcount != 0) {
1141 		/* Use unique dummy wait ident */
1142 		msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10);
1143 	}
1144 
1145 	dev_unlock();
1146 	if ((cdp->cdp_flags & CDP_UNREF_DTR) == 0) {
1147 		/* avoid out of order notify events */
1148 		notify_destroy(dev);
1149 	}
1150 	mtx_lock(&cdevpriv_mtx);
1151 	while ((p = LIST_FIRST(&cdp->cdp_fdpriv)) != NULL) {
1152 		devfs_destroy_cdevpriv(p);
1153 		mtx_lock(&cdevpriv_mtx);
1154 	}
1155 	mtx_unlock(&cdevpriv_mtx);
1156 	dev_lock();
1157 
1158 	dev->si_drv1 = 0;
1159 	dev->si_drv2 = 0;
1160 	bzero(&dev->__si_u, sizeof(dev->__si_u));
1161 
1162 	if (!(dev->si_flags & SI_ALIAS)) {
1163 		/* Remove from cdevsw list */
1164 		LIST_REMOVE(dev, si_list);
1165 
1166 		/* If cdevsw has no more struct cdev *'s, clean it */
1167 		if (LIST_EMPTY(&csw->d_devs)) {
1168 			fini_cdevsw(csw);
1169 			wakeup(&csw->d_devs);
1170 		}
1171 	}
1172 	dev->si_flags &= ~SI_ALIAS;
1173 	cdp->cdp_flags &= ~CDP_UNREF_DTR;
1174 	dev->si_refcount--;
1175 
1176 	if (dev->si_refcount > 0)
1177 		LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
1178 	else
1179 		dev_free_devlocked(dev);
1180 }
1181 
1182 static void
1183 delist_dev_locked(struct cdev *dev)
1184 {
1185 	struct cdev_priv *cdp;
1186 	struct cdev *child;
1187 
1188 	mtx_assert(&devmtx, MA_OWNED);
1189 	cdp = cdev2priv(dev);
1190 	if ((cdp->cdp_flags & CDP_UNREF_DTR) != 0)
1191 		return;
1192 	cdp->cdp_flags |= CDP_UNREF_DTR;
1193 	dev_refl(dev);
1194 	devfs_destroy(dev);
1195 	LIST_FOREACH(child, &dev->si_children, si_siblings)
1196 		delist_dev_locked(child);
1197 	dev_unlock();
1198 	/* ensure the destroy event is queued in order */
1199 	notify_destroy(dev);
1200 	dev_lock();
1201 }
1202 
1203 /*
1204  * This function will delist a character device and its children from
1205  * the directory listing and create a destroy event without waiting
1206  * for all character device references to go away. At some later point
1207  * destroy_dev() must be called to complete the character device
1208  * destruction. After calling this function the character device name
1209  * can instantly be re-used.
1210  */
1211 void
1212 delist_dev(struct cdev *dev)
1213 {
1214 
1215 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "delist_dev");
1216 	dev_lock();
1217 	delist_dev_locked(dev);
1218 	dev_unlock();
1219 }
1220 
1221 void
1222 destroy_dev(struct cdev *dev)
1223 {
1224 
1225 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "destroy_dev");
1226 	dev_lock();
1227 	destroy_devl(dev);
1228 	dev_unlock_and_free();
1229 }
1230 
1231 const char *
1232 devtoname(struct cdev *dev)
1233 {
1234 
1235 	return (dev->si_name);
1236 }
1237 
1238 int
1239 dev_stdclone(char *name, char **namep, const char *stem, int *unit)
1240 {
1241 	int u, i;
1242 
1243 	i = strlen(stem);
1244 	if (bcmp(stem, name, i) != 0)
1245 		return (0);
1246 	if (!isdigit(name[i]))
1247 		return (0);
1248 	u = 0;
1249 	if (name[i] == '0' && isdigit(name[i+1]))
1250 		return (0);
1251 	while (isdigit(name[i])) {
1252 		u *= 10;
1253 		u += name[i++] - '0';
1254 	}
1255 	if (u > 0xffffff)
1256 		return (0);
1257 	*unit = u;
1258 	if (namep)
1259 		*namep = &name[i];
1260 	if (name[i])
1261 		return (2);
1262 	return (1);
1263 }
1264 
1265 /*
1266  * Helper functions for cloning device drivers.
1267  *
1268  * The objective here is to make it unnecessary for the device drivers to
1269  * use rman or similar to manage their unit number space.  Due to the way
1270  * we do "on-demand" devices, using rman or other "private" methods
1271  * will be very tricky to lock down properly once we lock down this file.
1272  *
1273  * Instead we give the drivers these routines which puts the struct cdev *'s
1274  * that are to be managed on their own list, and gives the driver the ability
1275  * to ask for the first free unit number or a given specified unit number.
1276  *
1277  * In addition these routines support paired devices (pty, nmdm and similar)
1278  * by respecting a number of "flag" bits in the minor number.
1279  *
1280  */
1281 
1282 struct clonedevs {
1283 	LIST_HEAD(,cdev)	head;
1284 };
1285 
1286 void
1287 clone_setup(struct clonedevs **cdp)
1288 {
1289 
1290 	*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
1291 	LIST_INIT(&(*cdp)->head);
1292 }
1293 
1294 int
1295 clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up,
1296     struct cdev **dp, int extra)
1297 {
1298 	struct clonedevs *cd;
1299 	struct cdev *dev, *ndev, *dl, *de;
1300 	struct make_dev_args args;
1301 	int unit, low, u;
1302 
1303 	KASSERT(*cdp != NULL,
1304 	    ("clone_setup() not called in driver \"%s\"", csw->d_name));
1305 	KASSERT(!(extra & CLONE_UNITMASK),
1306 	    ("Illegal extra bits (0x%x) in clone_create", extra));
1307 	KASSERT(*up <= CLONE_UNITMASK,
1308 	    ("Too high unit (0x%x) in clone_create", *up));
1309 	KASSERT(csw->d_flags & D_NEEDMINOR,
1310 	    ("clone_create() on cdevsw without minor numbers"));
1311 
1312 
1313 	/*
1314 	 * Search the list for a lot of things in one go:
1315 	 *   A preexisting match is returned immediately.
1316 	 *   The lowest free unit number if we are passed -1, and the place
1317 	 *	 in the list where we should insert that new element.
1318 	 *   The place to insert a specified unit number, if applicable
1319 	 *       the end of the list.
1320 	 */
1321 	unit = *up;
1322 	ndev = devfs_alloc(MAKEDEV_WAITOK);
1323 	dev_lock();
1324 	prep_cdevsw(csw, MAKEDEV_WAITOK);
1325 	low = extra;
1326 	de = dl = NULL;
1327 	cd = *cdp;
1328 	LIST_FOREACH(dev, &cd->head, si_clone) {
1329 		KASSERT(dev->si_flags & SI_CLONELIST,
1330 		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
1331 		u = dev2unit(dev);
1332 		if (u == (unit | extra)) {
1333 			*dp = dev;
1334 			dev_unlock();
1335 			devfs_free(ndev);
1336 			return (0);
1337 		}
1338 		if (unit == -1 && u == low) {
1339 			low++;
1340 			de = dev;
1341 			continue;
1342 		} else if (u < (unit | extra)) {
1343 			de = dev;
1344 			continue;
1345 		} else if (u > (unit | extra)) {
1346 			dl = dev;
1347 			break;
1348 		}
1349 	}
1350 	if (unit == -1)
1351 		unit = low & CLONE_UNITMASK;
1352 	make_dev_args_init(&args);
1353 	args.mda_unit = unit | extra;
1354 	args.mda_devsw = csw;
1355 	dev = newdev(&args, ndev);
1356 	if (dev->si_flags & SI_CLONELIST) {
1357 		printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
1358 		printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra);
1359 		LIST_FOREACH(dev, &cd->head, si_clone) {
1360 			printf("\t%p %s\n", dev, dev->si_name);
1361 		}
1362 		panic("foo");
1363 	}
1364 	KASSERT(!(dev->si_flags & SI_CLONELIST),
1365 	    ("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
1366 	if (dl != NULL)
1367 		LIST_INSERT_BEFORE(dl, dev, si_clone);
1368 	else if (de != NULL)
1369 		LIST_INSERT_AFTER(de, dev, si_clone);
1370 	else
1371 		LIST_INSERT_HEAD(&cd->head, dev, si_clone);
1372 	dev->si_flags |= SI_CLONELIST;
1373 	*up = unit;
1374 	dev_unlock_and_free();
1375 	return (1);
1376 }
1377 
1378 /*
1379  * Kill everything still on the list.  The driver should already have
1380  * disposed of any softc hung of the struct cdev *'s at this time.
1381  */
1382 void
1383 clone_cleanup(struct clonedevs **cdp)
1384 {
1385 	struct cdev *dev;
1386 	struct cdev_priv *cp;
1387 	struct clonedevs *cd;
1388 
1389 	cd = *cdp;
1390 	if (cd == NULL)
1391 		return;
1392 	dev_lock();
1393 	while (!LIST_EMPTY(&cd->head)) {
1394 		dev = LIST_FIRST(&cd->head);
1395 		LIST_REMOVE(dev, si_clone);
1396 		KASSERT(dev->si_flags & SI_CLONELIST,
1397 		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
1398 		dev->si_flags &= ~SI_CLONELIST;
1399 		cp = cdev2priv(dev);
1400 		if (!(cp->cdp_flags & CDP_SCHED_DTR)) {
1401 			cp->cdp_flags |= CDP_SCHED_DTR;
1402 			KASSERT(dev->si_flags & SI_NAMED,
1403 				("Driver has goofed in cloning underways udev %jx unit %x",
1404 				(uintmax_t)dev2udev(dev), dev2unit(dev)));
1405 			destroy_devl(dev);
1406 		}
1407 	}
1408 	dev_unlock_and_free();
1409 	free(cd, M_DEVBUF);
1410 	*cdp = NULL;
1411 }
1412 
1413 static TAILQ_HEAD(, cdev_priv) dev_ddtr =
1414 	TAILQ_HEAD_INITIALIZER(dev_ddtr);
1415 static struct task dev_dtr_task = TASK_INITIALIZER(0, destroy_dev_tq, NULL);
1416 
1417 static void
1418 destroy_dev_tq(void *ctx, int pending)
1419 {
1420 	struct cdev_priv *cp;
1421 	struct cdev *dev;
1422 	void (*cb)(void *);
1423 	void *cb_arg;
1424 
1425 	dev_lock();
1426 	while (!TAILQ_EMPTY(&dev_ddtr)) {
1427 		cp = TAILQ_FIRST(&dev_ddtr);
1428 		dev = &cp->cdp_c;
1429 		KASSERT(cp->cdp_flags & CDP_SCHED_DTR,
1430 		    ("cdev %p in dev_destroy_tq without CDP_SCHED_DTR", cp));
1431 		TAILQ_REMOVE(&dev_ddtr, cp, cdp_dtr_list);
1432 		cb = cp->cdp_dtr_cb;
1433 		cb_arg = cp->cdp_dtr_cb_arg;
1434 		destroy_devl(dev);
1435 		dev_unlock_and_free();
1436 		dev_rel(dev);
1437 		if (cb != NULL)
1438 			cb(cb_arg);
1439 		dev_lock();
1440 	}
1441 	dev_unlock();
1442 }
1443 
1444 /*
1445  * devmtx shall be locked on entry. devmtx will be unlocked after
1446  * function return.
1447  */
1448 static int
1449 destroy_dev_sched_cbl(struct cdev *dev, void (*cb)(void *), void *arg)
1450 {
1451 	struct cdev_priv *cp;
1452 
1453 	mtx_assert(&devmtx, MA_OWNED);
1454 	cp = cdev2priv(dev);
1455 	if (cp->cdp_flags & CDP_SCHED_DTR) {
1456 		dev_unlock();
1457 		return (0);
1458 	}
1459 	dev_refl(dev);
1460 	cp->cdp_flags |= CDP_SCHED_DTR;
1461 	cp->cdp_dtr_cb = cb;
1462 	cp->cdp_dtr_cb_arg = arg;
1463 	TAILQ_INSERT_TAIL(&dev_ddtr, cp, cdp_dtr_list);
1464 	dev_unlock();
1465 	taskqueue_enqueue(taskqueue_swi_giant, &dev_dtr_task);
1466 	return (1);
1467 }
1468 
1469 int
1470 destroy_dev_sched_cb(struct cdev *dev, void (*cb)(void *), void *arg)
1471 {
1472 
1473 	dev_lock();
1474 	return (destroy_dev_sched_cbl(dev, cb, arg));
1475 }
1476 
1477 int
1478 destroy_dev_sched(struct cdev *dev)
1479 {
1480 
1481 	return (destroy_dev_sched_cb(dev, NULL, NULL));
1482 }
1483 
1484 void
1485 destroy_dev_drain(struct cdevsw *csw)
1486 {
1487 
1488 	dev_lock();
1489 	while (!LIST_EMPTY(&csw->d_devs)) {
1490 		msleep(&csw->d_devs, &devmtx, PRIBIO, "devscd", hz/10);
1491 	}
1492 	dev_unlock();
1493 }
1494 
1495 void
1496 drain_dev_clone_events(void)
1497 {
1498 
1499 	sx_xlock(&clone_drain_lock);
1500 	sx_xunlock(&clone_drain_lock);
1501 }
1502 
1503 #include "opt_ddb.h"
1504 #ifdef DDB
1505 #include <sys/kernel.h>
1506 
1507 #include <ddb/ddb.h>
1508 
1509 DB_SHOW_COMMAND(cdev, db_show_cdev)
1510 {
1511 	struct cdev_priv *cdp;
1512 	struct cdev *dev;
1513 	u_int flags;
1514 	char buf[512];
1515 
1516 	if (!have_addr) {
1517 		TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
1518 			dev = &cdp->cdp_c;
1519 			db_printf("%s %p\n", dev->si_name, dev);
1520 			if (db_pager_quit)
1521 				break;
1522 		}
1523 		return;
1524 	}
1525 
1526 	dev = (struct cdev *)addr;
1527 	cdp = cdev2priv(dev);
1528 	db_printf("dev %s ref %d use %ld thr %ld inuse %u fdpriv %p\n",
1529 	    dev->si_name, dev->si_refcount, dev->si_usecount,
1530 	    dev->si_threadcount, cdp->cdp_inuse, cdp->cdp_fdpriv.lh_first);
1531 	db_printf("devsw %p si_drv0 %d si_drv1 %p si_drv2 %p\n",
1532 	    dev->si_devsw, dev->si_drv0, dev->si_drv1, dev->si_drv2);
1533 	flags = dev->si_flags;
1534 #define	SI_FLAG(flag)	do {						\
1535 	if (flags & (flag)) {						\
1536 		if (buf[0] != '\0')					\
1537 			strlcat(buf, ", ", sizeof(buf));		\
1538 		strlcat(buf, (#flag) + 3, sizeof(buf));			\
1539 		flags &= ~(flag);					\
1540 	}								\
1541 } while (0)
1542 	buf[0] = '\0';
1543 	SI_FLAG(SI_ETERNAL);
1544 	SI_FLAG(SI_ALIAS);
1545 	SI_FLAG(SI_NAMED);
1546 	SI_FLAG(SI_CHEAPCLONE);
1547 	SI_FLAG(SI_CHILD);
1548 	SI_FLAG(SI_DUMPDEV);
1549 	SI_FLAG(SI_CLONELIST);
1550 	db_printf("si_flags %s\n", buf);
1551 
1552 	flags = cdp->cdp_flags;
1553 #define	CDP_FLAG(flag)	do {						\
1554 	if (flags & (flag)) {						\
1555 		if (buf[0] != '\0')					\
1556 			strlcat(buf, ", ", sizeof(buf));		\
1557 		strlcat(buf, (#flag) + 4, sizeof(buf));			\
1558 		flags &= ~(flag);					\
1559 	}								\
1560 } while (0)
1561 	buf[0] = '\0';
1562 	CDP_FLAG(CDP_ACTIVE);
1563 	CDP_FLAG(CDP_SCHED_DTR);
1564 	db_printf("cdp_flags %s\n", buf);
1565 }
1566 #endif
1567