xref: /freebsd/sys/kern/kern_conf.c (revision e0c4386e7e71d93b0edc0c8fa156263fc4a8b0b6)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
30 #include <sys/kernel.h>
31 #include <sys/systm.h>
32 #include <sys/bio.h>
33 #include <sys/devctl.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/sx.h>
43 #include <sys/ctype.h>
44 #include <sys/ucred.h>
45 #include <sys/taskqueue.h>
46 #include <machine/stdarg.h>
47 
48 #include <fs/devfs/devfs_int.h>
49 #include <vm/vm.h>
50 
51 static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
52 
53 struct mtx devmtx;
54 static void destroy_devl(struct cdev *dev);
55 static int destroy_dev_sched_cbl(struct cdev *dev,
56     void (*cb)(void *), void *arg);
57 static void destroy_dev_tq(void *ctx, int pending);
58 static void destroy_dev_tq_giant(void *ctx, int pending);
59 static int make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw,
60     int unit, struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
61     va_list ap);
62 
63 static struct cdev_priv_list cdevp_free_list =
64     TAILQ_HEAD_INITIALIZER(cdevp_free_list);
65 static SLIST_HEAD(free_cdevsw, cdevsw) cdevsw_gt_post_list =
66     SLIST_HEAD_INITIALIZER(cdevsw_gt_post_list);
67 
68 void
69 dev_lock(void)
70 {
71 
72 	mtx_lock(&devmtx);
73 }
74 
75 /*
76  * Free all the memory collected while the cdev mutex was
77  * locked. Since devmtx is after the system map mutex, free() cannot
78  * be called immediately and is postponed until cdev mutex can be
79  * dropped.
80  */
81 static void
82 dev_unlock_and_free(void)
83 {
84 	struct cdev_priv_list cdp_free;
85 	struct free_cdevsw csw_free;
86 	struct cdev_priv *cdp;
87 	struct cdevsw *csw;
88 
89 	dev_lock_assert_locked();
90 
91 	/*
92 	 * Make the local copy of the list heads while the dev_mtx is
93 	 * held. Free it later.
94 	 */
95 	TAILQ_INIT(&cdp_free);
96 	TAILQ_CONCAT(&cdp_free, &cdevp_free_list, cdp_list);
97 	csw_free = cdevsw_gt_post_list;
98 	SLIST_INIT(&cdevsw_gt_post_list);
99 
100 	mtx_unlock(&devmtx);
101 
102 	while ((cdp = TAILQ_FIRST(&cdp_free)) != NULL) {
103 		TAILQ_REMOVE(&cdp_free, cdp, cdp_list);
104 		devfs_free(&cdp->cdp_c);
105 	}
106 	while ((csw = SLIST_FIRST(&csw_free)) != NULL) {
107 		SLIST_REMOVE_HEAD(&csw_free, d_postfree_list);
108 		free(csw, M_DEVT);
109 	}
110 }
111 
112 static void
113 dev_free_devlocked(struct cdev *cdev)
114 {
115 	struct cdev_priv *cdp;
116 
117 	dev_lock_assert_locked();
118 	cdp = cdev2priv(cdev);
119 	KASSERT((cdp->cdp_flags & CDP_UNREF_DTR) == 0,
120 	    ("destroy_dev() was not called after delist_dev(%p)", cdev));
121 	KASSERT((cdp->cdp_flags & CDP_ON_ACTIVE_LIST) == 0,
122 	    ("%s: cdp %p (%s) on active list", __func__, cdp, cdev->si_name));
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 	dev_lock_assert_locked();
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 	dev_lock_assert_unlocked();
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 	dev_lock_assert_locked();
156 	dev->si_refcount++;
157 }
158 
159 void
160 dev_rel(struct cdev *dev)
161 {
162 	int flag = 0;
163 
164 	dev_lock_assert_unlocked();
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 	dev_lock_assert_unlocked();
185 	if ((dev->si_flags & SI_ETERNAL) != 0) {
186 		*ref = 0;
187 		return (dev->si_devsw);
188 	}
189 	cdp = cdev2priv(dev);
190 	mtx_lock(&cdp->cdp_threadlock);
191 	csw = dev->si_devsw;
192 	if (csw != NULL) {
193 		if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0)
194 			atomic_add_long(&dev->si_threadcount, 1);
195 		else
196 			csw = NULL;
197 	}
198 	mtx_unlock(&cdp->cdp_threadlock);
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 	dev_lock_assert_unlocked();
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 	VI_LOCK(vp);
227 	dev = vp->v_rdev;
228 	if (dev == NULL) {
229 		VI_UNLOCK(vp);
230 		return (NULL);
231 	}
232 	cdp = cdev2priv(dev);
233 	mtx_lock(&cdp->cdp_threadlock);
234 	if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0) {
235 		csw = dev->si_devsw;
236 		if (csw != NULL)
237 			atomic_add_long(&dev->si_threadcount, 1);
238 	}
239 	mtx_unlock(&cdp->cdp_threadlock);
240 	VI_UNLOCK(vp);
241 	if (csw != NULL) {
242 		*devp = dev;
243 		*ref = 1;
244 	}
245 	return (csw);
246 }
247 
248 void
249 dev_relthread(struct cdev *dev, int ref)
250 {
251 
252 	dev_lock_assert_unlocked();
253 	if (!ref)
254 		return;
255 	KASSERT(dev->si_threadcount > 0,
256 	    ("%s threadcount is wrong", dev->si_name));
257 	atomic_subtract_rel_long(&dev->si_threadcount, 1);
258 }
259 
260 int
261 nullop(void)
262 {
263 
264 	return (0);
265 }
266 
267 int
268 eopnotsupp(void)
269 {
270 
271 	return (EOPNOTSUPP);
272 }
273 
274 static int
275 enxio(void)
276 {
277 	return (ENXIO);
278 }
279 
280 static int
281 enodev(void)
282 {
283 	return (ENODEV);
284 }
285 
286 /* Define a dead_cdevsw for use when devices leave unexpectedly. */
287 
288 #define dead_open	(d_open_t *)enxio
289 #define dead_close	(d_close_t *)enxio
290 #define dead_read	(d_read_t *)enxio
291 #define dead_write	(d_write_t *)enxio
292 #define dead_ioctl	(d_ioctl_t *)enxio
293 #define dead_poll	(d_poll_t *)enodev
294 #define dead_mmap	(d_mmap_t *)enodev
295 
296 static void
297 dead_strategy(struct bio *bp)
298 {
299 
300 	biofinish(bp, NULL, ENXIO);
301 }
302 
303 #define dead_kqfilter	(d_kqfilter_t *)enxio
304 #define dead_mmap_single (d_mmap_single_t *)enodev
305 
306 static struct cdevsw dead_cdevsw = {
307 	.d_version =	D_VERSION,
308 	.d_open =	dead_open,
309 	.d_close =	dead_close,
310 	.d_read =	dead_read,
311 	.d_write =	dead_write,
312 	.d_ioctl =	dead_ioctl,
313 	.d_poll =	dead_poll,
314 	.d_mmap =	dead_mmap,
315 	.d_strategy =	dead_strategy,
316 	.d_name =	"dead",
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 static int
347 giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
348 {
349 	struct cdevsw *dsw;
350 	int ref, retval;
351 
352 	dsw = dev_refthread(dev, &ref);
353 	if (dsw == NULL)
354 		return (ENXIO);
355 	mtx_lock(&Giant);
356 	retval = dsw->d_gianttrick->d_open(dev, oflags, devtype, td);
357 	mtx_unlock(&Giant);
358 	dev_relthread(dev, ref);
359 	return (retval);
360 }
361 
362 static int
363 giant_fdopen(struct cdev *dev, int oflags, struct thread *td, struct file *fp)
364 {
365 	struct cdevsw *dsw;
366 	int ref, retval;
367 
368 	dsw = dev_refthread(dev, &ref);
369 	if (dsw == NULL)
370 		return (ENXIO);
371 	mtx_lock(&Giant);
372 	retval = dsw->d_gianttrick->d_fdopen(dev, oflags, td, fp);
373 	mtx_unlock(&Giant);
374 	dev_relthread(dev, ref);
375 	return (retval);
376 }
377 
378 static int
379 giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
380 {
381 	struct cdevsw *dsw;
382 	int ref, retval;
383 
384 	dsw = dev_refthread(dev, &ref);
385 	if (dsw == NULL)
386 		return (ENXIO);
387 	mtx_lock(&Giant);
388 	retval = dsw->d_gianttrick->d_close(dev, fflag, devtype, td);
389 	mtx_unlock(&Giant);
390 	dev_relthread(dev, ref);
391 	return (retval);
392 }
393 
394 static void
395 giant_strategy(struct bio *bp)
396 {
397 	struct cdevsw *dsw;
398 	struct cdev *dev;
399 	int ref;
400 
401 	dev = bp->bio_dev;
402 	dsw = dev_refthread(dev, &ref);
403 	if (dsw == NULL) {
404 		biofinish(bp, NULL, ENXIO);
405 		return;
406 	}
407 	mtx_lock(&Giant);
408 	dsw->d_gianttrick->d_strategy(bp);
409 	mtx_unlock(&Giant);
410 	dev_relthread(dev, ref);
411 }
412 
413 static int
414 giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
415 {
416 	struct cdevsw *dsw;
417 	int ref, retval;
418 
419 	dsw = dev_refthread(dev, &ref);
420 	if (dsw == NULL)
421 		return (ENXIO);
422 	mtx_lock(&Giant);
423 	retval = dsw->d_gianttrick->d_ioctl(dev, cmd, data, fflag, td);
424 	mtx_unlock(&Giant);
425 	dev_relthread(dev, ref);
426 	return (retval);
427 }
428 
429 static int
430 giant_read(struct cdev *dev, struct uio *uio, int ioflag)
431 {
432 	struct cdevsw *dsw;
433 	int ref, retval;
434 
435 	dsw = dev_refthread(dev, &ref);
436 	if (dsw == NULL)
437 		return (ENXIO);
438 	mtx_lock(&Giant);
439 	retval = dsw->d_gianttrick->d_read(dev, uio, ioflag);
440 	mtx_unlock(&Giant);
441 	dev_relthread(dev, ref);
442 	return (retval);
443 }
444 
445 static int
446 giant_write(struct cdev *dev, struct uio *uio, int ioflag)
447 {
448 	struct cdevsw *dsw;
449 	int ref, retval;
450 
451 	dsw = dev_refthread(dev, &ref);
452 	if (dsw == NULL)
453 		return (ENXIO);
454 	mtx_lock(&Giant);
455 	retval = dsw->d_gianttrick->d_write(dev, uio, ioflag);
456 	mtx_unlock(&Giant);
457 	dev_relthread(dev, ref);
458 	return (retval);
459 }
460 
461 static int
462 giant_poll(struct cdev *dev, int events, struct thread *td)
463 {
464 	struct cdevsw *dsw;
465 	int ref, retval;
466 
467 	dsw = dev_refthread(dev, &ref);
468 	if (dsw == NULL)
469 		return (ENXIO);
470 	mtx_lock(&Giant);
471 	retval = dsw->d_gianttrick->d_poll(dev, events, td);
472 	mtx_unlock(&Giant);
473 	dev_relthread(dev, ref);
474 	return (retval);
475 }
476 
477 static int
478 giant_kqfilter(struct cdev *dev, struct knote *kn)
479 {
480 	struct cdevsw *dsw;
481 	int ref, retval;
482 
483 	dsw = dev_refthread(dev, &ref);
484 	if (dsw == NULL)
485 		return (ENXIO);
486 	mtx_lock(&Giant);
487 	retval = dsw->d_gianttrick->d_kqfilter(dev, kn);
488 	mtx_unlock(&Giant);
489 	dev_relthread(dev, ref);
490 	return (retval);
491 }
492 
493 static int
494 giant_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, int nprot,
495     vm_memattr_t *memattr)
496 {
497 	struct cdevsw *dsw;
498 	int ref, retval;
499 
500 	dsw = dev_refthread(dev, &ref);
501 	if (dsw == NULL)
502 		return (ENXIO);
503 	mtx_lock(&Giant);
504 	retval = dsw->d_gianttrick->d_mmap(dev, offset, paddr, nprot,
505 	    memattr);
506 	mtx_unlock(&Giant);
507 	dev_relthread(dev, ref);
508 	return (retval);
509 }
510 
511 static int
512 giant_mmap_single(struct cdev *dev, vm_ooffset_t *offset, vm_size_t size,
513     vm_object_t *object, int nprot)
514 {
515 	struct cdevsw *dsw;
516 	int ref, retval;
517 
518 	dsw = dev_refthread(dev, &ref);
519 	if (dsw == NULL)
520 		return (ENXIO);
521 	mtx_lock(&Giant);
522 	retval = dsw->d_gianttrick->d_mmap_single(dev, offset, size, object,
523 	    nprot);
524 	mtx_unlock(&Giant);
525 	dev_relthread(dev, ref);
526 	return (retval);
527 }
528 
529 static void
530 notify(struct cdev *dev, const char *ev, int flags)
531 {
532 	static const char prefix[] = "cdev=";
533 	char *data;
534 	int namelen, mflags;
535 
536 	if (cold)
537 		return;
538 	mflags = (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK;
539 	namelen = strlen(dev->si_name);
540 	data = malloc(namelen + sizeof(prefix), M_TEMP, mflags);
541 	if (data == NULL)
542 		return;
543 	memcpy(data, prefix, sizeof(prefix) - 1);
544 	memcpy(data + sizeof(prefix) - 1, dev->si_name, namelen + 1);
545 	devctl_notify("DEVFS", "CDEV", ev, data);
546 	free(data, M_TEMP);
547 }
548 
549 static void
550 notify_create(struct cdev *dev, int flags)
551 {
552 
553 	notify(dev, "CREATE", flags);
554 }
555 
556 static void
557 notify_destroy(struct cdev *dev)
558 {
559 
560 	notify(dev, "DESTROY", MAKEDEV_WAITOK);
561 }
562 
563 static struct cdev *
564 newdev(struct make_dev_args *args, struct cdev *si)
565 {
566 	struct cdev *si2;
567 	struct cdevsw *csw;
568 
569 	dev_lock_assert_locked();
570 	csw = args->mda_devsw;
571 	si2 = NULL;
572 	if (csw->d_flags & D_NEEDMINOR) {
573 		/* We may want to return an existing device */
574 		LIST_FOREACH(si2, &csw->d_devs, si_list) {
575 			if (dev2unit(si2) == args->mda_unit) {
576 				dev_free_devlocked(si);
577 				si = si2;
578 				break;
579 			}
580 		}
581 
582 		/*
583 		 * If we're returning an existing device, we should make sure
584 		 * it isn't already initialized.  This would have been caught
585 		 * in consumers anyways, but it's good to catch such a case
586 		 * early.  We still need to complete initialization of the
587 		 * device, and we'll use whatever make_dev_args were passed in
588 		 * to do so.
589 		 */
590 		KASSERT(si2 == NULL || (si2->si_flags & SI_NAMED) == 0,
591 		    ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
592 		    args->mda_devsw->d_name, dev2unit(si2), devtoname(si2)));
593 	}
594 	si->si_drv0 = args->mda_unit;
595 	si->si_drv1 = args->mda_si_drv1;
596 	si->si_drv2 = args->mda_si_drv2;
597 	/* Only push to csw->d_devs if it's not a cloned device. */
598 	if (si2 == NULL) {
599 		si->si_devsw = csw;
600 		LIST_INSERT_HEAD(&csw->d_devs, si, si_list);
601 	} else {
602 		KASSERT(si->si_devsw == csw,
603 		    ("%s: inconsistent devsw between clone_create() and make_dev()",
604 		    __func__));
605 	}
606 	return (si);
607 }
608 
609 static void
610 fini_cdevsw(struct cdevsw *devsw)
611 {
612 	struct cdevsw *gt;
613 
614 	if (devsw->d_gianttrick != NULL) {
615 		gt = devsw->d_gianttrick;
616 		memcpy(devsw, gt, sizeof *devsw);
617 		cdevsw_free_devlocked(gt);
618 		devsw->d_gianttrick = NULL;
619 	}
620 	devsw->d_flags &= ~D_INIT;
621 }
622 
623 static int
624 prep_cdevsw(struct cdevsw *devsw, int flags)
625 {
626 	struct cdevsw *dsw2;
627 
628 	dev_lock_assert_locked();
629 	if (devsw->d_flags & D_INIT)
630 		return (0);
631 	if (devsw->d_flags & D_NEEDGIANT) {
632 		dev_unlock();
633 		dsw2 = malloc(sizeof *dsw2, M_DEVT,
634 		     (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK);
635 		dev_lock();
636 		if (dsw2 == NULL && !(devsw->d_flags & D_INIT))
637 			return (ENOMEM);
638 	} else
639 		dsw2 = NULL;
640 	if (devsw->d_flags & D_INIT) {
641 		if (dsw2 != NULL)
642 			cdevsw_free_devlocked(dsw2);
643 		return (0);
644 	}
645 
646 	if (devsw->d_version != D_VERSION_04) {
647 		printf(
648 		    "WARNING: Device driver \"%s\" has wrong version %s\n",
649 		    devsw->d_name == NULL ? "???" : devsw->d_name,
650 		    "and is disabled.  Recompile KLD module.");
651 		devsw->d_open = dead_open;
652 		devsw->d_close = dead_close;
653 		devsw->d_read = dead_read;
654 		devsw->d_write = dead_write;
655 		devsw->d_ioctl = dead_ioctl;
656 		devsw->d_poll = dead_poll;
657 		devsw->d_mmap = dead_mmap;
658 		devsw->d_mmap_single = dead_mmap_single;
659 		devsw->d_strategy = dead_strategy;
660 		devsw->d_kqfilter = dead_kqfilter;
661 	}
662 
663 	if ((devsw->d_flags & D_NEEDGIANT) != 0) {
664 		if ((devsw->d_flags & D_GIANTOK) == 0) {
665 			printf(
666 			    "WARNING: Device \"%s\" is Giant locked and may be "
667 			    "deleted before FreeBSD 15.0.\n",
668 			    devsw->d_name == NULL ? "???" : devsw->d_name);
669 		}
670 		if (devsw->d_gianttrick == NULL) {
671 			memcpy(dsw2, devsw, sizeof *dsw2);
672 			devsw->d_gianttrick = dsw2;
673 			dsw2 = NULL;
674 		}
675 	}
676 
677 #define FIXUP(member, noop, giant) 				\
678 	do {							\
679 		if (devsw->member == NULL) {			\
680 			devsw->member = noop;			\
681 		} else if (devsw->d_flags & D_NEEDGIANT)	\
682 			devsw->member = giant;			\
683 		}						\
684 	while (0)
685 
686 	FIXUP(d_open,		null_open,	giant_open);
687 	FIXUP(d_fdopen,		NULL,		giant_fdopen);
688 	FIXUP(d_close,		null_close,	giant_close);
689 	FIXUP(d_read,		no_read,	giant_read);
690 	FIXUP(d_write,		no_write,	giant_write);
691 	FIXUP(d_ioctl,		no_ioctl,	giant_ioctl);
692 	FIXUP(d_poll,		no_poll,	giant_poll);
693 	FIXUP(d_mmap,		no_mmap,	giant_mmap);
694 	FIXUP(d_strategy,	no_strategy,	giant_strategy);
695 	FIXUP(d_kqfilter,	no_kqfilter,	giant_kqfilter);
696 	FIXUP(d_mmap_single,	no_mmap_single,	giant_mmap_single);
697 
698 	LIST_INIT(&devsw->d_devs);
699 
700 	devsw->d_flags |= D_INIT;
701 
702 	if (dsw2 != NULL)
703 		cdevsw_free_devlocked(dsw2);
704 	return (0);
705 }
706 
707 static int
708 prep_devname(struct cdev *dev, const char *fmt, va_list ap)
709 {
710 	int len;
711 	char *from, *q, *s, *to;
712 
713 	dev_lock_assert_locked();
714 
715 	len = vsnrprintf(dev->si_name, sizeof(dev->si_name), 32, fmt, ap);
716 	if (len > sizeof(dev->si_name) - 1)
717 		return (ENAMETOOLONG);
718 
719 	/* Strip leading slashes. */
720 	for (from = dev->si_name; *from == '/'; from++)
721 		;
722 
723 	for (to = dev->si_name; *from != '\0'; from++, to++) {
724 		/*
725 		 * Spaces and double quotation marks cause
726 		 * problems for the devctl(4) protocol.
727 		 * Reject names containing those characters.
728 		 */
729 		if (isspace(*from) || *from == '"')
730 			return (EINVAL);
731 		/* Treat multiple sequential slashes as single. */
732 		while (from[0] == '/' && from[1] == '/')
733 			from++;
734 		/* Trailing slash is considered invalid. */
735 		if (from[0] == '/' && from[1] == '\0')
736 			return (EINVAL);
737 		*to = *from;
738 	}
739 	*to = '\0';
740 
741 	if (dev->si_name[0] == '\0')
742 		return (EINVAL);
743 
744 	/* Disallow "." and ".." components. */
745 	for (s = dev->si_name;;) {
746 		for (q = s; *q != '/' && *q != '\0'; q++)
747 			;
748 		if (q - s == 1 && s[0] == '.')
749 			return (EINVAL);
750 		if (q - s == 2 && s[0] == '.' && s[1] == '.')
751 			return (EINVAL);
752 		if (*q != '/')
753 			break;
754 		s = q + 1;
755 	}
756 
757 	if (devfs_dev_exists(dev->si_name) != 0)
758 		return (EEXIST);
759 
760 	return (0);
761 }
762 
763 void
764 make_dev_args_init_impl(struct make_dev_args *args, size_t sz)
765 {
766 
767 	bzero(args, sz);
768 	args->mda_size = sz;
769 }
770 
771 static int
772 make_dev_sv(struct make_dev_args *args1, struct cdev **dres,
773     const char *fmt, va_list ap)
774 {
775 	struct cdev *dev, *dev_new;
776 	struct make_dev_args args;
777 	int res;
778 
779 	bzero(&args, sizeof(args));
780 	if (sizeof(args) < args1->mda_size)
781 		return (EINVAL);
782 	bcopy(args1, &args, args1->mda_size);
783 	KASSERT((args.mda_flags & MAKEDEV_WAITOK) == 0 ||
784 	    (args.mda_flags & MAKEDEV_NOWAIT) == 0,
785 	    ("make_dev_sv: both WAITOK and NOWAIT specified"));
786 	dev_new = devfs_alloc(args.mda_flags);
787 	if (dev_new == NULL)
788 		return (ENOMEM);
789 	dev_lock();
790 	res = prep_cdevsw(args.mda_devsw, args.mda_flags);
791 	if (res != 0) {
792 		dev_unlock();
793 		devfs_free(dev_new);
794 		return (res);
795 	}
796 	dev = newdev(&args, dev_new);
797 	if ((dev->si_flags & SI_NAMED) == 0) {
798 		res = prep_devname(dev, fmt, ap);
799 		if (res != 0) {
800 			if ((args.mda_flags & MAKEDEV_CHECKNAME) == 0) {
801 				panic(
802 			"make_dev_sv: bad si_name (error=%d, si_name=%s)",
803 				    res, dev->si_name);
804 			}
805 			if (dev == dev_new) {
806 				LIST_REMOVE(dev, si_list);
807 				dev_unlock();
808 				devfs_free(dev);
809 			} else
810 				dev_unlock();
811 			return (res);
812 		}
813 	}
814 	if ((args.mda_flags & MAKEDEV_REF) != 0)
815 		dev_refl(dev);
816 	if ((args.mda_flags & MAKEDEV_ETERNAL) != 0)
817 		dev->si_flags |= SI_ETERNAL;
818 	KASSERT(!(dev->si_flags & SI_NAMED),
819 	    ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
820 	    args.mda_devsw->d_name, dev2unit(dev), devtoname(dev)));
821 	dev->si_flags |= SI_NAMED;
822 	if (args.mda_cr != NULL)
823 		dev->si_cred = crhold(args.mda_cr);
824 	dev->si_uid = args.mda_uid;
825 	dev->si_gid = args.mda_gid;
826 	dev->si_mode = args.mda_mode;
827 
828 	devfs_create(dev);
829 	clean_unrhdrl(devfs_inos);
830 	dev_unlock_and_free();
831 
832 	notify_create(dev, args.mda_flags);
833 
834 	*dres = dev;
835 	return (0);
836 }
837 
838 int
839 make_dev_s(struct make_dev_args *args, struct cdev **dres,
840     const char *fmt, ...)
841 {
842 	va_list ap;
843 	int res;
844 
845 	va_start(ap, fmt);
846 	res = make_dev_sv(args, dres, fmt, ap);
847 	va_end(ap);
848 	return (res);
849 }
850 
851 static int
852 make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw, int unit,
853     struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
854     va_list ap)
855 {
856 	struct make_dev_args args;
857 
858 	make_dev_args_init(&args);
859 	args.mda_flags = flags;
860 	args.mda_devsw = devsw;
861 	args.mda_cr = cr;
862 	args.mda_uid = uid;
863 	args.mda_gid = gid;
864 	args.mda_mode = mode;
865 	args.mda_unit = unit;
866 	return (make_dev_sv(&args, dres, fmt, ap));
867 }
868 
869 struct cdev *
870 make_dev(struct cdevsw *devsw, int unit, uid_t uid, gid_t gid, int mode,
871     const char *fmt, ...)
872 {
873 	struct cdev *dev;
874 	va_list ap;
875 	int res __unused;
876 
877 	va_start(ap, fmt);
878 	res = make_dev_credv(0, &dev, devsw, unit, NULL, uid, gid, mode, fmt,
879 		      ap);
880 	va_end(ap);
881 	KASSERT(res == 0 && dev != NULL,
882 	    ("make_dev: failed make_dev_credv (error=%d)", res));
883 	return (dev);
884 }
885 
886 struct cdev *
887 make_dev_cred(struct cdevsw *devsw, int unit, struct ucred *cr, uid_t uid,
888     gid_t gid, int mode, const char *fmt, ...)
889 {
890 	struct cdev *dev;
891 	va_list ap;
892 	int res __unused;
893 
894 	va_start(ap, fmt);
895 	res = make_dev_credv(0, &dev, devsw, unit, cr, uid, gid, mode, fmt, ap);
896 	va_end(ap);
897 
898 	KASSERT(res == 0 && dev != NULL,
899 	    ("make_dev_cred: failed make_dev_credv (error=%d)", res));
900 	return (dev);
901 }
902 
903 struct cdev *
904 make_dev_credf(int flags, struct cdevsw *devsw, int unit, struct ucred *cr,
905     uid_t uid, gid_t gid, int mode, const char *fmt, ...)
906 {
907 	struct cdev *dev;
908 	va_list ap;
909 	int res;
910 
911 	va_start(ap, fmt);
912 	res = make_dev_credv(flags, &dev, devsw, unit, cr, uid, gid, mode,
913 	    fmt, ap);
914 	va_end(ap);
915 
916 	KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
917 	    ((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
918 	    ("make_dev_credf: failed make_dev_credv (error=%d)", res));
919 	return (res == 0 ? dev : NULL);
920 }
921 
922 int
923 make_dev_p(int flags, struct cdev **cdev, struct cdevsw *devsw,
924     struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt, ...)
925 {
926 	va_list ap;
927 	int res;
928 
929 	va_start(ap, fmt);
930 	res = make_dev_credv(flags, cdev, devsw, 0, cr, uid, gid, mode,
931 	    fmt, ap);
932 	va_end(ap);
933 
934 	KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
935 	    ((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
936 	    ("make_dev_p: failed make_dev_credv (error=%d)", res));
937 	return (res);
938 }
939 
940 static void
941 dev_dependsl(struct cdev *pdev, struct cdev *cdev)
942 {
943 
944 	cdev->si_parent = pdev;
945 	cdev->si_flags |= SI_CHILD;
946 	LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
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 	dev_lock_assert_locked();
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 	mtx_lock(&cdp->cdp_threadlock);
1137 	csw = dev->si_devsw;
1138 	dev->si_devsw = NULL;	/* already NULL for SI_ALIAS */
1139 	while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
1140 		csw->d_purge(dev);
1141 		mtx_unlock(&cdp->cdp_threadlock);
1142 		msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
1143 		mtx_lock(&cdp->cdp_threadlock);
1144 		if (dev->si_threadcount)
1145 			printf("Still %lu threads in %s\n",
1146 			    dev->si_threadcount, devtoname(dev));
1147 	}
1148 	while (dev->si_threadcount != 0) {
1149 		/* Use unique dummy wait ident */
1150 		mtx_unlock(&cdp->cdp_threadlock);
1151 		msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10);
1152 		mtx_lock(&cdp->cdp_threadlock);
1153 	}
1154 
1155 	mtx_unlock(&cdp->cdp_threadlock);
1156 	dev_unlock();
1157 	if ((cdp->cdp_flags & CDP_UNREF_DTR) == 0) {
1158 		/* avoid out of order notify events */
1159 		notify_destroy(dev);
1160 	}
1161 	mtx_lock(&cdevpriv_mtx);
1162 	while ((p = LIST_FIRST(&cdp->cdp_fdpriv)) != NULL) {
1163 		devfs_destroy_cdevpriv(p);
1164 		mtx_lock(&cdevpriv_mtx);
1165 	}
1166 	mtx_unlock(&cdevpriv_mtx);
1167 	dev_lock();
1168 
1169 	dev->si_drv1 = 0;
1170 	dev->si_drv2 = 0;
1171 
1172 	if (!(dev->si_flags & SI_ALIAS)) {
1173 		/* Remove from cdevsw list */
1174 		LIST_REMOVE(dev, si_list);
1175 
1176 		/* If cdevsw has no more struct cdev *'s, clean it */
1177 		if (LIST_EMPTY(&csw->d_devs)) {
1178 			fini_cdevsw(csw);
1179 			wakeup(&csw->d_devs);
1180 		}
1181 	}
1182 	dev->si_flags &= ~SI_ALIAS;
1183 	cdp->cdp_flags &= ~CDP_UNREF_DTR;
1184 	dev->si_refcount--;
1185 
1186 	if (dev->si_refcount > 0)
1187 		LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
1188 	else
1189 		dev_free_devlocked(dev);
1190 }
1191 
1192 static void
1193 delist_dev_locked(struct cdev *dev)
1194 {
1195 	struct cdev_priv *cdp;
1196 	struct cdev *child;
1197 
1198 	dev_lock_assert_locked();
1199 	cdp = cdev2priv(dev);
1200 	if ((cdp->cdp_flags & CDP_UNREF_DTR) != 0)
1201 		return;
1202 	cdp->cdp_flags |= CDP_UNREF_DTR;
1203 	dev_refl(dev);
1204 	devfs_destroy(dev);
1205 	LIST_FOREACH(child, &dev->si_children, si_siblings)
1206 		delist_dev_locked(child);
1207 	dev_unlock();
1208 	/* ensure the destroy event is queued in order */
1209 	notify_destroy(dev);
1210 	dev_lock();
1211 }
1212 
1213 /*
1214  * This function will delist a character device and its children from
1215  * the directory listing and create a destroy event without waiting
1216  * for all character device references to go away. At some later point
1217  * destroy_dev() must be called to complete the character device
1218  * destruction. After calling this function the character device name
1219  * can instantly be re-used.
1220  */
1221 void
1222 delist_dev(struct cdev *dev)
1223 {
1224 
1225 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "delist_dev");
1226 	dev_lock();
1227 	delist_dev_locked(dev);
1228 	dev_unlock();
1229 }
1230 
1231 void
1232 destroy_dev(struct cdev *dev)
1233 {
1234 
1235 	WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "destroy_dev");
1236 	dev_lock();
1237 	destroy_devl(dev);
1238 	dev_unlock_and_free();
1239 }
1240 
1241 const char *
1242 devtoname(struct cdev *dev)
1243 {
1244 
1245 	return (dev->si_name);
1246 }
1247 
1248 int
1249 dev_stdclone(char *name, char **namep, const char *stem, int *unit)
1250 {
1251 	int u, i;
1252 
1253 	i = strlen(stem);
1254 	if (strncmp(stem, name, i) != 0)
1255 		return (0);
1256 	if (!isdigit(name[i]))
1257 		return (0);
1258 	u = 0;
1259 	if (name[i] == '0' && isdigit(name[i+1]))
1260 		return (0);
1261 	while (isdigit(name[i])) {
1262 		u *= 10;
1263 		u += name[i++] - '0';
1264 	}
1265 	if (u > 0xffffff)
1266 		return (0);
1267 	*unit = u;
1268 	if (namep)
1269 		*namep = &name[i];
1270 	if (name[i])
1271 		return (2);
1272 	return (1);
1273 }
1274 
1275 /*
1276  * Helper functions for cloning device drivers.
1277  *
1278  * The objective here is to make it unnecessary for the device drivers to
1279  * use rman or similar to manage their unit number space.  Due to the way
1280  * we do "on-demand" devices, using rman or other "private" methods
1281  * will be very tricky to lock down properly once we lock down this file.
1282  *
1283  * Instead we give the drivers these routines which puts the struct cdev *'s
1284  * that are to be managed on their own list, and gives the driver the ability
1285  * to ask for the first free unit number or a given specified unit number.
1286  *
1287  * In addition these routines support paired devices (pty, nmdm and similar)
1288  * by respecting a number of "flag" bits in the minor number.
1289  *
1290  */
1291 
1292 struct clonedevs {
1293 	LIST_HEAD(,cdev)	head;
1294 };
1295 
1296 void
1297 clone_setup(struct clonedevs **cdp)
1298 {
1299 
1300 	*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
1301 	LIST_INIT(&(*cdp)->head);
1302 }
1303 
1304 int
1305 clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up,
1306     struct cdev **dp, int extra)
1307 {
1308 	struct clonedevs *cd;
1309 	struct cdev *dev, *ndev, *dl, *de;
1310 	struct make_dev_args args;
1311 	int unit, low, u;
1312 
1313 	KASSERT(*cdp != NULL,
1314 	    ("clone_setup() not called in driver \"%s\"", csw->d_name));
1315 	KASSERT(!(extra & CLONE_UNITMASK),
1316 	    ("Illegal extra bits (0x%x) in clone_create", extra));
1317 	KASSERT(*up <= CLONE_UNITMASK,
1318 	    ("Too high unit (0x%x) in clone_create", *up));
1319 	KASSERT(csw->d_flags & D_NEEDMINOR,
1320 	    ("clone_create() on cdevsw without minor numbers"));
1321 
1322 	/*
1323 	 * Search the list for a lot of things in one go:
1324 	 *   A preexisting match is returned immediately.
1325 	 *   The lowest free unit number if we are passed -1, and the place
1326 	 *	 in the list where we should insert that new element.
1327 	 *   The place to insert a specified unit number, if applicable
1328 	 *       the end of the list.
1329 	 */
1330 	unit = *up;
1331 	ndev = devfs_alloc(MAKEDEV_WAITOK);
1332 	dev_lock();
1333 	prep_cdevsw(csw, MAKEDEV_WAITOK);
1334 	low = extra;
1335 	de = dl = NULL;
1336 	cd = *cdp;
1337 	LIST_FOREACH(dev, &cd->head, si_clone) {
1338 		KASSERT(dev->si_flags & SI_CLONELIST,
1339 		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
1340 		u = dev2unit(dev);
1341 		if (u == (unit | extra)) {
1342 			*dp = dev;
1343 			dev_unlock();
1344 			devfs_free(ndev);
1345 			return (0);
1346 		}
1347 		if (unit == -1 && u == low) {
1348 			low++;
1349 			de = dev;
1350 			continue;
1351 		} else if (u < (unit | extra)) {
1352 			de = dev;
1353 			continue;
1354 		} else if (u > (unit | extra)) {
1355 			dl = dev;
1356 			break;
1357 		}
1358 	}
1359 	if (unit == -1)
1360 		unit = low & CLONE_UNITMASK;
1361 	make_dev_args_init(&args);
1362 	args.mda_unit = unit | extra;
1363 	args.mda_devsw = csw;
1364 	dev = newdev(&args, ndev);
1365 	if (dev->si_flags & SI_CLONELIST) {
1366 		printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
1367 		printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra);
1368 		LIST_FOREACH(dev, &cd->head, si_clone) {
1369 			printf("\t%p %s\n", dev, dev->si_name);
1370 		}
1371 		panic("foo");
1372 	}
1373 	KASSERT(!(dev->si_flags & SI_CLONELIST),
1374 	    ("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
1375 	if (dl != NULL)
1376 		LIST_INSERT_BEFORE(dl, dev, si_clone);
1377 	else if (de != NULL)
1378 		LIST_INSERT_AFTER(de, dev, si_clone);
1379 	else
1380 		LIST_INSERT_HEAD(&cd->head, dev, si_clone);
1381 	dev->si_flags |= SI_CLONELIST;
1382 	*up = unit;
1383 	dev_unlock_and_free();
1384 	return (1);
1385 }
1386 
1387 /*
1388  * Kill everything still on the list.  The driver should already have
1389  * disposed of any softc hung of the struct cdev *'s at this time.
1390  */
1391 void
1392 clone_cleanup(struct clonedevs **cdp)
1393 {
1394 	struct cdev *dev;
1395 	struct cdev_priv *cp;
1396 	struct clonedevs *cd;
1397 
1398 	cd = *cdp;
1399 	if (cd == NULL)
1400 		return;
1401 	dev_lock();
1402 	while (!LIST_EMPTY(&cd->head)) {
1403 		dev = LIST_FIRST(&cd->head);
1404 		LIST_REMOVE(dev, si_clone);
1405 		KASSERT(dev->si_flags & SI_CLONELIST,
1406 		    ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
1407 		dev->si_flags &= ~SI_CLONELIST;
1408 		cp = cdev2priv(dev);
1409 		if (!(cp->cdp_flags & CDP_SCHED_DTR)) {
1410 			cp->cdp_flags |= CDP_SCHED_DTR;
1411 			KASSERT(dev->si_flags & SI_NAMED,
1412 				("Driver has goofed in cloning underways udev %jx unit %x",
1413 				(uintmax_t)dev2udev(dev), dev2unit(dev)));
1414 			destroy_devl(dev);
1415 		}
1416 	}
1417 	dev_unlock_and_free();
1418 	free(cd, M_DEVBUF);
1419 	*cdp = NULL;
1420 }
1421 
1422 static TAILQ_HEAD(, cdev_priv) dev_ddtr =
1423 	TAILQ_HEAD_INITIALIZER(dev_ddtr);
1424 static TAILQ_HEAD(, cdev_priv) dev_ddtr_giant =
1425 	TAILQ_HEAD_INITIALIZER(dev_ddtr_giant);
1426 static struct task dev_dtr_task = TASK_INITIALIZER(0, destroy_dev_tq, &dev_ddtr);
1427 static struct task dev_dtr_task_giant = TASK_INITIALIZER(0, destroy_dev_tq_giant,
1428     &dev_ddtr_giant);
1429 
1430 static void
1431 destroy_dev_tq(void *ctx, int pending)
1432 {
1433 	TAILQ_HEAD(, cdev_priv) *ddtr = ctx;
1434 	struct cdev_priv *cp;
1435 	struct cdev *dev;
1436 	void (*cb)(void *);
1437 	void *cb_arg;
1438 
1439 	dev_lock();
1440 	while (!TAILQ_EMPTY(ddtr)) {
1441 		cp = TAILQ_FIRST(ddtr);
1442 		dev = &cp->cdp_c;
1443 		KASSERT(cp->cdp_flags & CDP_SCHED_DTR,
1444 		    ("cdev %p in dev_destroy_tq without CDP_SCHED_DTR", cp));
1445 		TAILQ_REMOVE(ddtr, cp, cdp_dtr_list);
1446 		cb = cp->cdp_dtr_cb;
1447 		cb_arg = cp->cdp_dtr_cb_arg;
1448 		destroy_devl(dev);
1449 		dev_unlock_and_free();
1450 		dev_rel(dev);
1451 		if (cb != NULL)
1452 			cb(cb_arg);
1453 		dev_lock();
1454 	}
1455 	dev_unlock();
1456 }
1457 
1458 static void
1459 destroy_dev_tq_giant(void *ctx, int pending)
1460 {
1461 	mtx_lock(&Giant);
1462 	destroy_dev_tq(ctx, pending);
1463 	mtx_unlock(&Giant);
1464 }
1465 
1466 /*
1467  * devmtx shall be locked on entry. devmtx will be unlocked after
1468  * function return.
1469  */
1470 static int
1471 destroy_dev_sched_cbl(struct cdev *dev, void (*cb)(void *), void *arg)
1472 {
1473 	struct cdev_priv *cp;
1474 	bool need_giant;
1475 
1476 	dev_lock_assert_locked();
1477 	cp = cdev2priv(dev);
1478 	if (cp->cdp_flags & CDP_SCHED_DTR) {
1479 		dev_unlock();
1480 		return (0);
1481 	}
1482 	dev_refl(dev);
1483 	cp->cdp_flags |= CDP_SCHED_DTR;
1484 	cp->cdp_dtr_cb = cb;
1485 	cp->cdp_dtr_cb_arg = arg;
1486 	need_giant = (dev->si_devsw->d_flags & D_NEEDGIANT) != 0;
1487 	if (need_giant)
1488 		TAILQ_INSERT_TAIL(&dev_ddtr_giant, cp, cdp_dtr_list);
1489 	else
1490 		TAILQ_INSERT_TAIL(&dev_ddtr, cp, cdp_dtr_list);
1491 	dev_unlock();
1492 	if (need_giant)
1493 		taskqueue_enqueue(taskqueue_thread, &dev_dtr_task_giant);
1494 	else
1495 		taskqueue_enqueue(taskqueue_thread, &dev_dtr_task);
1496 	return (1);
1497 }
1498 
1499 int
1500 destroy_dev_sched_cb(struct cdev *dev, void (*cb)(void *), void *arg)
1501 {
1502 
1503 	dev_lock();
1504 	return (destroy_dev_sched_cbl(dev, cb, arg));
1505 }
1506 
1507 int
1508 destroy_dev_sched(struct cdev *dev)
1509 {
1510 
1511 	return (destroy_dev_sched_cb(dev, NULL, NULL));
1512 }
1513 
1514 void
1515 destroy_dev_drain(struct cdevsw *csw)
1516 {
1517 
1518 	dev_lock();
1519 	while (!LIST_EMPTY(&csw->d_devs)) {
1520 		msleep(&csw->d_devs, &devmtx, PRIBIO, "devscd", hz/10);
1521 	}
1522 	dev_unlock();
1523 }
1524 
1525 #include "opt_ddb.h"
1526 #ifdef DDB
1527 #include <sys/kernel.h>
1528 
1529 #include <ddb/ddb.h>
1530 
1531 DB_SHOW_COMMAND(cdev, db_show_cdev)
1532 {
1533 	struct cdev_priv *cdp;
1534 	struct cdev *dev;
1535 	u_int flags;
1536 	char buf[512];
1537 
1538 	if (!have_addr) {
1539 		TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
1540 			dev = &cdp->cdp_c;
1541 			db_printf("%s %p\n", dev->si_name, dev);
1542 			if (db_pager_quit)
1543 				break;
1544 		}
1545 		return;
1546 	}
1547 
1548 	dev = (struct cdev *)addr;
1549 	cdp = cdev2priv(dev);
1550 	db_printf("dev %s ref %d use %ld thr %ld inuse %u fdpriv %p\n",
1551 	    dev->si_name, dev->si_refcount, dev->si_usecount,
1552 	    dev->si_threadcount, cdp->cdp_inuse, cdp->cdp_fdpriv.lh_first);
1553 	db_printf("devsw %p si_drv0 %d si_drv1 %p si_drv2 %p\n",
1554 	    dev->si_devsw, dev->si_drv0, dev->si_drv1, dev->si_drv2);
1555 	flags = dev->si_flags;
1556 #define	SI_FLAG(flag)	do {						\
1557 	if (flags & (flag)) {						\
1558 		if (buf[0] != '\0')					\
1559 			strlcat(buf, ", ", sizeof(buf));		\
1560 		strlcat(buf, (#flag) + 3, sizeof(buf));			\
1561 		flags &= ~(flag);					\
1562 	}								\
1563 } while (0)
1564 	buf[0] = '\0';
1565 	SI_FLAG(SI_ETERNAL);
1566 	SI_FLAG(SI_ALIAS);
1567 	SI_FLAG(SI_NAMED);
1568 	SI_FLAG(SI_CHILD);
1569 	SI_FLAG(SI_DUMPDEV);
1570 	SI_FLAG(SI_CLONELIST);
1571 	db_printf("si_flags %s\n", buf);
1572 
1573 	flags = cdp->cdp_flags;
1574 #define	CDP_FLAG(flag)	do {						\
1575 	if (flags & (flag)) {						\
1576 		if (buf[0] != '\0')					\
1577 			strlcat(buf, ", ", sizeof(buf));		\
1578 		strlcat(buf, (#flag) + 4, sizeof(buf));			\
1579 		flags &= ~(flag);					\
1580 	}								\
1581 } while (0)
1582 	buf[0] = '\0';
1583 	CDP_FLAG(CDP_ACTIVE);
1584 	CDP_FLAG(CDP_SCHED_DTR);
1585 	db_printf("cdp_flags %s\n", buf);
1586 }
1587 #endif
1588