FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_conf.c
1 /*-
2 * Copyright (c) 1999-2002 Poul-Henning Kamp
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD: releng/8.2/sys/kern/kern_conf.c 216611 2010-12-21 09:31:48Z thompsa $");
29
30 #include <sys/param.h>
31 #include <sys/kernel.h>
32 #include <sys/systm.h>
33 #include <sys/bus.h>
34 #include <sys/bio.h>
35 #include <sys/lock.h>
36 #include <sys/mutex.h>
37 #include <sys/module.h>
38 #include <sys/malloc.h>
39 #include <sys/conf.h>
40 #include <sys/vnode.h>
41 #include <sys/queue.h>
42 #include <sys/poll.h>
43 #include <sys/sx.h>
44 #include <sys/ctype.h>
45 #include <sys/ucred.h>
46 #include <sys/taskqueue.h>
47 #include <machine/stdarg.h>
48
49 #include <fs/devfs/devfs_int.h>
50 #include <vm/vm.h>
51
52 static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
53
54 struct mtx devmtx;
55 static void destroy_devl(struct cdev *dev);
56 static int destroy_dev_sched_cbl(struct cdev *dev,
57 void (*cb)(void *), void *arg);
58 static int make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw,
59 int unit, struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
60 va_list ap);
61
62 static struct cdev_priv_list cdevp_free_list =
63 TAILQ_HEAD_INITIALIZER(cdevp_free_list);
64 static SLIST_HEAD(free_cdevsw, cdevsw) cdevsw_gt_post_list =
65 SLIST_HEAD_INITIALIZER(cdevsw_gt_post_list);
66
67 void
68 dev_lock(void)
69 {
70
71 mtx_lock(&devmtx);
72 }
73
74 /*
75 * Free all the memory collected while the cdev mutex was
76 * locked. Since devmtx is after the system map mutex, free() cannot
77 * be called immediately and is postponed until cdev mutex can be
78 * dropped.
79 */
80 static void
81 dev_unlock_and_free(void)
82 {
83 struct cdev_priv_list cdp_free;
84 struct free_cdevsw csw_free;
85 struct cdev_priv *cdp;
86 struct cdevsw *csw;
87
88 mtx_assert(&devmtx, MA_OWNED);
89
90 /*
91 * Make the local copy of the list heads while the dev_mtx is
92 * held. Free it later.
93 */
94 TAILQ_INIT(&cdp_free);
95 TAILQ_CONCAT(&cdp_free, &cdevp_free_list, cdp_list);
96 csw_free = cdevsw_gt_post_list;
97 SLIST_INIT(&cdevsw_gt_post_list);
98
99 mtx_unlock(&devmtx);
100
101 while ((cdp = TAILQ_FIRST(&cdp_free)) != NULL) {
102 TAILQ_REMOVE(&cdp_free, cdp, cdp_list);
103 devfs_free(&cdp->cdp_c);
104 }
105 while ((csw = SLIST_FIRST(&csw_free)) != NULL) {
106 SLIST_REMOVE_HEAD(&csw_free, d_postfree_list);
107 free(csw, M_DEVT);
108 }
109 }
110
111 static void
112 dev_free_devlocked(struct cdev *cdev)
113 {
114 struct cdev_priv *cdp;
115
116 mtx_assert(&devmtx, MA_OWNED);
117 cdp = cdev2priv(cdev);
118 TAILQ_INSERT_HEAD(&cdevp_free_list, cdp, cdp_list);
119 }
120
121 static void
122 cdevsw_free_devlocked(struct cdevsw *csw)
123 {
124
125 mtx_assert(&devmtx, MA_OWNED);
126 SLIST_INSERT_HEAD(&cdevsw_gt_post_list, csw, d_postfree_list);
127 }
128
129 void
130 dev_unlock(void)
131 {
132
133 mtx_unlock(&devmtx);
134 }
135
136 void
137 dev_ref(struct cdev *dev)
138 {
139
140 mtx_assert(&devmtx, MA_NOTOWNED);
141 mtx_lock(&devmtx);
142 dev->si_refcount++;
143 mtx_unlock(&devmtx);
144 }
145
146 void
147 dev_refl(struct cdev *dev)
148 {
149
150 mtx_assert(&devmtx, MA_OWNED);
151 dev->si_refcount++;
152 }
153
154 void
155 dev_rel(struct cdev *dev)
156 {
157 int flag = 0;
158
159 mtx_assert(&devmtx, MA_NOTOWNED);
160 dev_lock();
161 dev->si_refcount--;
162 KASSERT(dev->si_refcount >= 0,
163 ("dev_rel(%s) gave negative count", devtoname(dev)));
164 #if 0
165 if (dev->si_usecount == 0 &&
166 (dev->si_flags & SI_CHEAPCLONE) && (dev->si_flags & SI_NAMED))
167 ;
168 else
169 #endif
170 if (dev->si_devsw == NULL && dev->si_refcount == 0) {
171 LIST_REMOVE(dev, si_list);
172 flag = 1;
173 }
174 dev_unlock();
175 if (flag)
176 devfs_free(dev);
177 }
178
179 struct cdevsw *
180 dev_refthread(struct cdev *dev, int *ref)
181 {
182 struct cdevsw *csw;
183 struct cdev_priv *cdp;
184
185 mtx_assert(&devmtx, MA_NOTOWNED);
186 if ((dev->si_flags & SI_ETERNAL) != 0) {
187 *ref = 0;
188 return (dev->si_devsw);
189 }
190 dev_lock();
191 csw = dev->si_devsw;
192 if (csw != NULL) {
193 cdp = cdev2priv(dev);
194 if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0)
195 dev->si_threadcount++;
196 else
197 csw = NULL;
198 }
199 dev_unlock();
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 dev->si_threadcount++;
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 dev_lock();
254 KASSERT(dev->si_threadcount > 0,
255 ("%s threadcount is wrong", dev->si_name));
256 dev->si_threadcount--;
257 dev_unlock();
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_dump (dumper_t *)enxio
304 #define dead_kqfilter (d_kqfilter_t *)enxio
305 #define dead_mmap_single (d_mmap_single_t *)enodev
306
307 static struct cdevsw dead_cdevsw = {
308 .d_version = D_VERSION,
309 .d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */
310 .d_open = dead_open,
311 .d_close = dead_close,
312 .d_read = dead_read,
313 .d_write = dead_write,
314 .d_ioctl = dead_ioctl,
315 .d_poll = dead_poll,
316 .d_mmap = dead_mmap,
317 .d_strategy = dead_strategy,
318 .d_name = "dead",
319 .d_dump = dead_dump,
320 .d_kqfilter = dead_kqfilter,
321 .d_mmap_single = dead_mmap_single
322 };
323
324 /* Default methods if driver does not specify method */
325
326 #define null_open (d_open_t *)nullop
327 #define null_close (d_close_t *)nullop
328 #define no_read (d_read_t *)enodev
329 #define no_write (d_write_t *)enodev
330 #define no_ioctl (d_ioctl_t *)enodev
331 #define no_mmap (d_mmap2_t *)enodev
332 #define no_kqfilter (d_kqfilter_t *)enodev
333 #define no_mmap_single (d_mmap_single_t *)enodev
334
335 static void
336 no_strategy(struct bio *bp)
337 {
338
339 biofinish(bp, NULL, ENODEV);
340 }
341
342 static int
343 no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
344 {
345
346 return (poll_no_poll(events));
347 }
348
349 #define no_dump (dumper_t *)enodev
350
351 static int
352 giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
353 {
354 struct cdevsw *dsw;
355 int ref, retval;
356
357 dsw = dev_refthread(dev, &ref);
358 if (dsw == NULL)
359 return (ENXIO);
360 mtx_lock(&Giant);
361 retval = dsw->d_gianttrick->d_open(dev, oflags, devtype, td);
362 mtx_unlock(&Giant);
363 dev_relthread(dev, ref);
364 return (retval);
365 }
366
367 static int
368 giant_fdopen(struct cdev *dev, int oflags, struct thread *td, struct file *fp)
369 {
370 struct cdevsw *dsw;
371 int ref, retval;
372
373 dsw = dev_refthread(dev, &ref);
374 if (dsw == NULL)
375 return (ENXIO);
376 mtx_lock(&Giant);
377 retval = dsw->d_gianttrick->d_fdopen(dev, oflags, td, fp);
378 mtx_unlock(&Giant);
379 dev_relthread(dev, ref);
380 return (retval);
381 }
382
383 static int
384 giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
385 {
386 struct cdevsw *dsw;
387 int ref, retval;
388
389 dsw = dev_refthread(dev, &ref);
390 if (dsw == NULL)
391 return (ENXIO);
392 mtx_lock(&Giant);
393 retval = dsw->d_gianttrick->d_close(dev, fflag, devtype, td);
394 mtx_unlock(&Giant);
395 dev_relthread(dev, ref);
396 return (retval);
397 }
398
399 static void
400 giant_strategy(struct bio *bp)
401 {
402 struct cdevsw *dsw;
403 struct cdev *dev;
404 int ref;
405
406 dev = bp->bio_dev;
407 dsw = dev_refthread(dev, &ref);
408 if (dsw == NULL) {
409 biofinish(bp, NULL, ENXIO);
410 return;
411 }
412 mtx_lock(&Giant);
413 dsw->d_gianttrick->d_strategy(bp);
414 mtx_unlock(&Giant);
415 dev_relthread(dev, ref);
416 }
417
418 static int
419 giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
420 {
421 struct cdevsw *dsw;
422 int ref, retval;
423
424 dsw = dev_refthread(dev, &ref);
425 if (dsw == NULL)
426 return (ENXIO);
427 mtx_lock(&Giant);
428 retval = dsw->d_gianttrick->d_ioctl(dev, cmd, data, fflag, td);
429 mtx_unlock(&Giant);
430 dev_relthread(dev, ref);
431 return (retval);
432 }
433
434 static int
435 giant_read(struct cdev *dev, struct uio *uio, int ioflag)
436 {
437 struct cdevsw *dsw;
438 int ref, retval;
439
440 dsw = dev_refthread(dev, &ref);
441 if (dsw == NULL)
442 return (ENXIO);
443 mtx_lock(&Giant);
444 retval = dsw->d_gianttrick->d_read(dev, uio, ioflag);
445 mtx_unlock(&Giant);
446 dev_relthread(dev, ref);
447 return (retval);
448 }
449
450 static int
451 giant_write(struct cdev *dev, struct uio *uio, int ioflag)
452 {
453 struct cdevsw *dsw;
454 int ref, retval;
455
456 dsw = dev_refthread(dev, &ref);
457 if (dsw == NULL)
458 return (ENXIO);
459 mtx_lock(&Giant);
460 retval = dsw->d_gianttrick->d_write(dev, uio, ioflag);
461 mtx_unlock(&Giant);
462 dev_relthread(dev, ref);
463 return (retval);
464 }
465
466 static int
467 giant_poll(struct cdev *dev, int events, struct thread *td)
468 {
469 struct cdevsw *dsw;
470 int ref, retval;
471
472 dsw = dev_refthread(dev, &ref);
473 if (dsw == NULL)
474 return (ENXIO);
475 mtx_lock(&Giant);
476 retval = dsw->d_gianttrick->d_poll(dev, events, td);
477 mtx_unlock(&Giant);
478 dev_relthread(dev, ref);
479 return (retval);
480 }
481
482 static int
483 giant_kqfilter(struct cdev *dev, struct knote *kn)
484 {
485 struct cdevsw *dsw;
486 int ref, retval;
487
488 dsw = dev_refthread(dev, &ref);
489 if (dsw == NULL)
490 return (ENXIO);
491 mtx_lock(&Giant);
492 retval = dsw->d_gianttrick->d_kqfilter(dev, kn);
493 mtx_unlock(&Giant);
494 dev_relthread(dev, ref);
495 return (retval);
496 }
497
498 static int
499 giant_mmap(struct cdev *dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot,
500 vm_memattr_t *memattr)
501 {
502 struct cdevsw *dsw;
503 int ref, retval;
504
505 dsw = dev_refthread(dev, &ref);
506 if (dsw == NULL)
507 return (ENXIO);
508 mtx_lock(&Giant);
509 if (dsw->d_gianttrick->d_flags & D_MMAP2)
510 retval = dsw->d_gianttrick->d_mmap2(dev, offset, paddr, nprot,
511 memattr);
512 else
513 retval = dsw->d_gianttrick->d_mmap(dev, offset, paddr, nprot);
514 mtx_unlock(&Giant);
515 dev_relthread(dev, ref);
516 return (retval);
517 }
518
519 static int
520 giant_mmap_single(struct cdev *dev, vm_ooffset_t *offset, vm_size_t size,
521 vm_object_t *object, int nprot)
522 {
523 struct cdevsw *dsw;
524 int ref, retval;
525
526 dsw = dev_refthread(dev, &ref);
527 if (dsw == NULL)
528 return (ENXIO);
529 mtx_lock(&Giant);
530 retval = dsw->d_gianttrick->d_mmap_single(dev, offset, size, object,
531 nprot);
532 mtx_unlock(&Giant);
533 dev_relthread(dev, ref);
534 return (retval);
535 }
536
537 static void
538 notify(struct cdev *dev, const char *ev, int flags)
539 {
540 static const char prefix[] = "cdev=";
541 char *data;
542 int namelen, mflags;
543
544 if (cold)
545 return;
546 mflags = (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK;
547 namelen = strlen(dev->si_name);
548 data = malloc(namelen + sizeof(prefix), M_TEMP, mflags);
549 if (data == NULL)
550 return;
551 memcpy(data, prefix, sizeof(prefix) - 1);
552 memcpy(data + sizeof(prefix) - 1, dev->si_name, namelen + 1);
553 devctl_notify_f("DEVFS", "CDEV", ev, data, mflags);
554 free(data, M_TEMP);
555 }
556
557 static void
558 notify_create(struct cdev *dev, int flags)
559 {
560
561 notify(dev, "CREATE", flags);
562 }
563
564 static void
565 notify_destroy(struct cdev *dev)
566 {
567
568 notify(dev, "DESTROY", MAKEDEV_WAITOK);
569 }
570
571 static struct cdev *
572 newdev(struct cdevsw *csw, int unit, struct cdev *si)
573 {
574 struct cdev *si2;
575
576 mtx_assert(&devmtx, MA_OWNED);
577 if (csw->d_flags & D_NEEDMINOR) {
578 /* We may want to return an existing device */
579 LIST_FOREACH(si2, &csw->d_devs, si_list) {
580 if (dev2unit(si2) == unit) {
581 dev_free_devlocked(si);
582 return (si2);
583 }
584 }
585 }
586 si->si_drv0 = unit;
587 si->si_devsw = csw;
588 LIST_INSERT_HEAD(&csw->d_devs, si, si_list);
589 return (si);
590 }
591
592 static void
593 fini_cdevsw(struct cdevsw *devsw)
594 {
595 struct cdevsw *gt;
596
597 if (devsw->d_gianttrick != NULL) {
598 gt = devsw->d_gianttrick;
599 memcpy(devsw, gt, sizeof *devsw);
600 cdevsw_free_devlocked(gt);
601 devsw->d_gianttrick = NULL;
602 }
603 devsw->d_flags &= ~D_INIT;
604 }
605
606 static int
607 prep_cdevsw(struct cdevsw *devsw, int flags)
608 {
609 struct cdevsw *dsw2;
610
611 mtx_assert(&devmtx, MA_OWNED);
612 if (devsw->d_flags & D_INIT)
613 return (0);
614 if (devsw->d_flags & D_NEEDGIANT) {
615 dev_unlock();
616 dsw2 = malloc(sizeof *dsw2, M_DEVT,
617 (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK);
618 dev_lock();
619 if (dsw2 == NULL && !(devsw->d_flags & D_INIT))
620 return (ENOMEM);
621 } else
622 dsw2 = NULL;
623 if (devsw->d_flags & D_INIT) {
624 if (dsw2 != NULL)
625 cdevsw_free_devlocked(dsw2);
626 return (0);
627 }
628
629 if (devsw->d_version != D_VERSION_01 &&
630 devsw->d_version != D_VERSION_02) {
631 printf(
632 "WARNING: Device driver \"%s\" has wrong version %s\n",
633 devsw->d_name == NULL ? "???" : devsw->d_name,
634 "and is disabled. Recompile KLD module.");
635 devsw->d_open = dead_open;
636 devsw->d_close = dead_close;
637 devsw->d_read = dead_read;
638 devsw->d_write = dead_write;
639 devsw->d_ioctl = dead_ioctl;
640 devsw->d_poll = dead_poll;
641 devsw->d_mmap = dead_mmap;
642 devsw->d_strategy = dead_strategy;
643 devsw->d_dump = dead_dump;
644 devsw->d_kqfilter = dead_kqfilter;
645 }
646 if (devsw->d_version == D_VERSION_01)
647 devsw->d_mmap_single = NULL;
648
649 if (devsw->d_flags & D_NEEDGIANT) {
650 if (devsw->d_gianttrick == NULL) {
651 memcpy(dsw2, devsw, sizeof *dsw2);
652 devsw->d_gianttrick = dsw2;
653 devsw->d_flags |= D_MMAP2;
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_mmap2, 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 make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw, int unit,
692 struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
693 va_list ap)
694 {
695 struct cdev *dev;
696 int i, res;
697
698 KASSERT((flags & MAKEDEV_WAITOK) == 0 || (flags & MAKEDEV_NOWAIT) == 0,
699 ("make_dev_credv: both WAITOK and NOWAIT specified"));
700 dev = devfs_alloc(flags);
701 if (dev == NULL)
702 return (ENOMEM);
703 dev_lock();
704 res = prep_cdevsw(devsw, flags);
705 if (res != 0) {
706 dev_unlock();
707 devfs_free(dev);
708 return (res);
709 }
710 dev = newdev(devsw, unit, dev);
711 if (flags & MAKEDEV_REF)
712 dev_refl(dev);
713 if (flags & MAKEDEV_ETERNAL)
714 dev->si_flags |= SI_ETERNAL;
715 if (dev->si_flags & SI_CHEAPCLONE &&
716 dev->si_flags & SI_NAMED) {
717 /*
718 * This is allowed as it removes races and generally
719 * simplifies cloning devices.
720 * XXX: still ??
721 */
722 dev_unlock_and_free();
723 *dres = dev;
724 return (0);
725 }
726 KASSERT(!(dev->si_flags & SI_NAMED),
727 ("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
728 devsw->d_name, dev2unit(dev), devtoname(dev)));
729
730 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
731 if (i > (sizeof dev->__si_namebuf - 1)) {
732 printf("WARNING: Device name truncated! (%s)\n",
733 dev->__si_namebuf);
734 }
735
736 dev->si_flags |= SI_NAMED;
737 if (cr != NULL)
738 dev->si_cred = crhold(cr);
739 dev->si_uid = uid;
740 dev->si_gid = gid;
741 dev->si_mode = mode;
742
743 devfs_create(dev);
744 clean_unrhdrl(devfs_inos);
745 dev_unlock_and_free();
746
747 notify_create(dev, flags);
748
749 *dres = dev;
750 return (0);
751 }
752
753 struct cdev *
754 make_dev(struct cdevsw *devsw, int unit, uid_t uid, gid_t gid, int mode,
755 const char *fmt, ...)
756 {
757 struct cdev *dev;
758 va_list ap;
759 int res;
760
761 va_start(ap, fmt);
762 res = make_dev_credv(0, &dev, devsw, unit, NULL, uid, gid, mode, fmt,
763 ap);
764 va_end(ap);
765 KASSERT(res == 0 && dev != NULL, ("make_dev: failed make_dev_credv"));
766 return (dev);
767 }
768
769 struct cdev *
770 make_dev_cred(struct cdevsw *devsw, int unit, struct ucred *cr, uid_t uid,
771 gid_t gid, int mode, const char *fmt, ...)
772 {
773 struct cdev *dev;
774 va_list ap;
775 int res;
776
777 va_start(ap, fmt);
778 res = make_dev_credv(0, &dev, devsw, unit, cr, uid, gid, mode, fmt, ap);
779 va_end(ap);
780
781 KASSERT(res == 0 && dev != NULL,
782 ("make_dev_cred: failed make_dev_credv"));
783 return (dev);
784 }
785
786 struct cdev *
787 make_dev_credf(int flags, struct cdevsw *devsw, int unit, struct ucred *cr,
788 uid_t uid, gid_t gid, int mode, const char *fmt, ...)
789 {
790 struct cdev *dev;
791 va_list ap;
792 int res;
793
794 va_start(ap, fmt);
795 res = make_dev_credv(flags, &dev, devsw, unit, cr, uid, gid, mode,
796 fmt, ap);
797 va_end(ap);
798
799 KASSERT((flags & MAKEDEV_NOWAIT) != 0 || res == 0,
800 ("make_dev_credf: failed make_dev_credv"));
801 return (res == 0 ? dev : NULL);
802 }
803
804 int
805 make_dev_p(int flags, struct cdev **cdev, struct cdevsw *devsw,
806 struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt, ...)
807 {
808 va_list ap;
809 int res;
810
811 va_start(ap, fmt);
812 res = make_dev_credv(flags, cdev, devsw, 0, cr, uid, gid, mode,
813 fmt, ap);
814 va_end(ap);
815
816 KASSERT((flags & MAKEDEV_NOWAIT) != 0 || res == 0,
817 ("make_dev_p: failed make_dev_credv"));
818 return (res);
819 }
820
821 static void
822 dev_dependsl(struct cdev *pdev, struct cdev *cdev)
823 {
824
825 cdev->si_parent = pdev;
826 cdev->si_flags |= SI_CHILD;
827 LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
828 }
829
830
831 void
832 dev_depends(struct cdev *pdev, struct cdev *cdev)
833 {
834
835 dev_lock();
836 dev_dependsl(pdev, cdev);
837 dev_unlock();
838 }
839
840 struct cdev *
841 make_dev_alias(struct cdev *pdev, const char *fmt, ...)
842 {
843 struct cdev *dev;
844 va_list ap;
845 int i;
846
847 KASSERT(pdev != NULL, ("NULL pdev"));
848 dev = devfs_alloc(MAKEDEV_WAITOK);
849 dev_lock();
850 dev->si_flags |= SI_ALIAS;
851 dev->si_flags |= SI_NAMED;
852 va_start(ap, fmt);
853 i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
854 if (i > (sizeof dev->__si_namebuf - 1)) {
855 printf("WARNING: Device name truncated! (%s)\n",
856 dev->__si_namebuf);
857 }
858 va_end(ap);
859
860 devfs_create(dev);
861 dev_dependsl(pdev, dev);
862 clean_unrhdrl(devfs_inos);
863 dev_unlock();
864
865 notify_create(dev, MAKEDEV_WAITOK);
866
867 return (dev);
868 }
869
870 static void
871 destroy_devl(struct cdev *dev)
872 {
873 struct cdevsw *csw;
874 struct cdev_privdata *p;
875
876 mtx_assert(&devmtx, MA_OWNED);
877 KASSERT(dev->si_flags & SI_NAMED,
878 ("WARNING: Driver mistake: destroy_dev on %d\n", dev2unit(dev)));
879 KASSERT((dev->si_flags & SI_ETERNAL) == 0,
880 ("WARNING: Driver mistake: destroy_dev on eternal %d\n",
881 dev2unit(dev)));
882
883 devfs_destroy(dev);
884
885 /* Remove name marking */
886 dev->si_flags &= ~SI_NAMED;
887
888 /* If we are a child, remove us from the parents list */
889 if (dev->si_flags & SI_CHILD) {
890 LIST_REMOVE(dev, si_siblings);
891 dev->si_flags &= ~SI_CHILD;
892 }
893
894 /* Kill our children */
895 while (!LIST_EMPTY(&dev->si_children))
896 destroy_devl(LIST_FIRST(&dev->si_children));
897
898 /* Remove from clone list */
899 if (dev->si_flags & SI_CLONELIST) {
900 LIST_REMOVE(dev, si_clone);
901 dev->si_flags &= ~SI_CLONELIST;
902 }
903
904 dev->si_refcount++; /* Avoid race with dev_rel() */
905 csw = dev->si_devsw;
906 dev->si_devsw = NULL; /* already NULL for SI_ALIAS */
907 while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
908 csw->d_purge(dev);
909 msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
910 if (dev->si_threadcount)
911 printf("Still %lu threads in %s\n",
912 dev->si_threadcount, devtoname(dev));
913 }
914 while (dev->si_threadcount != 0) {
915 /* Use unique dummy wait ident */
916 msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10);
917 }
918
919 dev_unlock();
920 notify_destroy(dev);
921 mtx_lock(&cdevpriv_mtx);
922 while ((p = LIST_FIRST(&cdev2priv(dev)->cdp_fdpriv)) != NULL) {
923 devfs_destroy_cdevpriv(p);
924 mtx_lock(&cdevpriv_mtx);
925 }
926 mtx_unlock(&cdevpriv_mtx);
927 dev_lock();
928
929 dev->si_drv1 = 0;
930 dev->si_drv2 = 0;
931 bzero(&dev->__si_u, sizeof(dev->__si_u));
932
933 if (!(dev->si_flags & SI_ALIAS)) {
934 /* Remove from cdevsw list */
935 LIST_REMOVE(dev, si_list);
936
937 /* If cdevsw has no more struct cdev *'s, clean it */
938 if (LIST_EMPTY(&csw->d_devs)) {
939 fini_cdevsw(csw);
940 wakeup(&csw->d_devs);
941 }
942 }
943 dev->si_flags &= ~SI_ALIAS;
944 dev->si_refcount--; /* Avoid race with dev_rel() */
945
946 if (dev->si_refcount > 0) {
947 LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
948 } else {
949 dev_free_devlocked(dev);
950 }
951 }
952
953 void
954 destroy_dev(struct cdev *dev)
955 {
956
957 WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "destroy_dev");
958 dev_lock();
959 destroy_devl(dev);
960 dev_unlock_and_free();
961 }
962
963 const char *
964 devtoname(struct cdev *dev)
965 {
966
967 return (dev->si_name);
968 }
969
970 int
971 dev_stdclone(char *name, char **namep, const char *stem, int *unit)
972 {
973 int u, i;
974
975 i = strlen(stem);
976 if (bcmp(stem, name, i) != 0)
977 return (0);
978 if (!isdigit(name[i]))
979 return (0);
980 u = 0;
981 if (name[i] == '' && isdigit(name[i+1]))
982 return (0);
983 while (isdigit(name[i])) {
984 u *= 10;
985 u += name[i++] - '';
986 }
987 if (u > 0xffffff)
988 return (0);
989 *unit = u;
990 if (namep)
991 *namep = &name[i];
992 if (name[i])
993 return (2);
994 return (1);
995 }
996
997 /*
998 * Helper functions for cloning device drivers.
999 *
1000 * The objective here is to make it unnecessary for the device drivers to
1001 * use rman or similar to manage their unit number space. Due to the way
1002 * we do "on-demand" devices, using rman or other "private" methods
1003 * will be very tricky to lock down properly once we lock down this file.
1004 *
1005 * Instead we give the drivers these routines which puts the struct cdev *'s
1006 * that are to be managed on their own list, and gives the driver the ability
1007 * to ask for the first free unit number or a given specified unit number.
1008 *
1009 * In addition these routines support paired devices (pty, nmdm and similar)
1010 * by respecting a number of "flag" bits in the minor number.
1011 *
1012 */
1013
1014 struct clonedevs {
1015 LIST_HEAD(,cdev) head;
1016 };
1017
1018 void
1019 clone_setup(struct clonedevs **cdp)
1020 {
1021
1022 *cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
1023 LIST_INIT(&(*cdp)->head);
1024 }
1025
1026 int
1027 clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up,
1028 struct cdev **dp, int extra)
1029 {
1030 struct clonedevs *cd;
1031 struct cdev *dev, *ndev, *dl, *de;
1032 int unit, low, u;
1033
1034 KASSERT(*cdp != NULL,
1035 ("clone_setup() not called in driver \"%s\"", csw->d_name));
1036 KASSERT(!(extra & CLONE_UNITMASK),
1037 ("Illegal extra bits (0x%x) in clone_create", extra));
1038 KASSERT(*up <= CLONE_UNITMASK,
1039 ("Too high unit (0x%x) in clone_create", *up));
1040 KASSERT(csw->d_flags & D_NEEDMINOR,
1041 ("clone_create() on cdevsw without minor numbers"));
1042
1043
1044 /*
1045 * Search the list for a lot of things in one go:
1046 * A preexisting match is returned immediately.
1047 * The lowest free unit number if we are passed -1, and the place
1048 * in the list where we should insert that new element.
1049 * The place to insert a specified unit number, if applicable
1050 * the end of the list.
1051 */
1052 unit = *up;
1053 ndev = devfs_alloc(MAKEDEV_WAITOK);
1054 dev_lock();
1055 prep_cdevsw(csw, MAKEDEV_WAITOK);
1056 low = extra;
1057 de = dl = NULL;
1058 cd = *cdp;
1059 LIST_FOREACH(dev, &cd->head, si_clone) {
1060 KASSERT(dev->si_flags & SI_CLONELIST,
1061 ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
1062 u = dev2unit(dev);
1063 if (u == (unit | extra)) {
1064 *dp = dev;
1065 dev_unlock();
1066 devfs_free(ndev);
1067 return (0);
1068 }
1069 if (unit == -1 && u == low) {
1070 low++;
1071 de = dev;
1072 continue;
1073 } else if (u < (unit | extra)) {
1074 de = dev;
1075 continue;
1076 } else if (u > (unit | extra)) {
1077 dl = dev;
1078 break;
1079 }
1080 }
1081 if (unit == -1)
1082 unit = low & CLONE_UNITMASK;
1083 dev = newdev(csw, unit | extra, ndev);
1084 if (dev->si_flags & SI_CLONELIST) {
1085 printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
1086 printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra);
1087 LIST_FOREACH(dev, &cd->head, si_clone) {
1088 printf("\t%p %s\n", dev, dev->si_name);
1089 }
1090 panic("foo");
1091 }
1092 KASSERT(!(dev->si_flags & SI_CLONELIST),
1093 ("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
1094 if (dl != NULL)
1095 LIST_INSERT_BEFORE(dl, dev, si_clone);
1096 else if (de != NULL)
1097 LIST_INSERT_AFTER(de, dev, si_clone);
1098 else
1099 LIST_INSERT_HEAD(&cd->head, dev, si_clone);
1100 dev->si_flags |= SI_CLONELIST;
1101 *up = unit;
1102 dev_unlock_and_free();
1103 return (1);
1104 }
1105
1106 /*
1107 * Kill everything still on the list. The driver should already have
1108 * disposed of any softc hung of the struct cdev *'s at this time.
1109 */
1110 void
1111 clone_cleanup(struct clonedevs **cdp)
1112 {
1113 struct cdev *dev;
1114 struct cdev_priv *cp;
1115 struct clonedevs *cd;
1116
1117 cd = *cdp;
1118 if (cd == NULL)
1119 return;
1120 dev_lock();
1121 while (!LIST_EMPTY(&cd->head)) {
1122 dev = LIST_FIRST(&cd->head);
1123 LIST_REMOVE(dev, si_clone);
1124 KASSERT(dev->si_flags & SI_CLONELIST,
1125 ("Dev %p(%s) should be on clonelist", dev, dev->si_name));
1126 dev->si_flags &= ~SI_CLONELIST;
1127 cp = cdev2priv(dev);
1128 if (!(cp->cdp_flags & CDP_SCHED_DTR)) {
1129 cp->cdp_flags |= CDP_SCHED_DTR;
1130 KASSERT(dev->si_flags & SI_NAMED,
1131 ("Driver has goofed in cloning underways udev %x unit %x", dev2udev(dev), dev2unit(dev)));
1132 destroy_devl(dev);
1133 }
1134 }
1135 dev_unlock_and_free();
1136 free(cd, M_DEVBUF);
1137 *cdp = NULL;
1138 }
1139
1140 static TAILQ_HEAD(, cdev_priv) dev_ddtr =
1141 TAILQ_HEAD_INITIALIZER(dev_ddtr);
1142 static struct task dev_dtr_task;
1143
1144 static void
1145 destroy_dev_tq(void *ctx, int pending)
1146 {
1147 struct cdev_priv *cp;
1148 struct cdev *dev;
1149 void (*cb)(void *);
1150 void *cb_arg;
1151
1152 dev_lock();
1153 while (!TAILQ_EMPTY(&dev_ddtr)) {
1154 cp = TAILQ_FIRST(&dev_ddtr);
1155 dev = &cp->cdp_c;
1156 KASSERT(cp->cdp_flags & CDP_SCHED_DTR,
1157 ("cdev %p in dev_destroy_tq without CDP_SCHED_DTR", cp));
1158 TAILQ_REMOVE(&dev_ddtr, cp, cdp_dtr_list);
1159 cb = cp->cdp_dtr_cb;
1160 cb_arg = cp->cdp_dtr_cb_arg;
1161 destroy_devl(dev);
1162 dev_unlock_and_free();
1163 dev_rel(dev);
1164 if (cb != NULL)
1165 cb(cb_arg);
1166 dev_lock();
1167 }
1168 dev_unlock();
1169 }
1170
1171 /*
1172 * devmtx shall be locked on entry. devmtx will be unlocked after
1173 * function return.
1174 */
1175 static int
1176 destroy_dev_sched_cbl(struct cdev *dev, void (*cb)(void *), void *arg)
1177 {
1178 struct cdev_priv *cp;
1179
1180 mtx_assert(&devmtx, MA_OWNED);
1181 cp = cdev2priv(dev);
1182 if (cp->cdp_flags & CDP_SCHED_DTR) {
1183 dev_unlock();
1184 return (0);
1185 }
1186 dev_refl(dev);
1187 cp->cdp_flags |= CDP_SCHED_DTR;
1188 cp->cdp_dtr_cb = cb;
1189 cp->cdp_dtr_cb_arg = arg;
1190 TAILQ_INSERT_TAIL(&dev_ddtr, cp, cdp_dtr_list);
1191 dev_unlock();
1192 taskqueue_enqueue(taskqueue_swi_giant, &dev_dtr_task);
1193 return (1);
1194 }
1195
1196 int
1197 destroy_dev_sched_cb(struct cdev *dev, void (*cb)(void *), void *arg)
1198 {
1199
1200 dev_lock();
1201 return (destroy_dev_sched_cbl(dev, cb, arg));
1202 }
1203
1204 int
1205 destroy_dev_sched(struct cdev *dev)
1206 {
1207
1208 return (destroy_dev_sched_cb(dev, NULL, NULL));
1209 }
1210
1211 void
1212 destroy_dev_drain(struct cdevsw *csw)
1213 {
1214
1215 dev_lock();
1216 while (!LIST_EMPTY(&csw->d_devs)) {
1217 msleep(&csw->d_devs, &devmtx, PRIBIO, "devscd", hz/10);
1218 }
1219 dev_unlock();
1220 }
1221
1222 void
1223 drain_dev_clone_events(void)
1224 {
1225
1226 sx_xlock(&clone_drain_lock);
1227 sx_xunlock(&clone_drain_lock);
1228 }
1229
1230 static void
1231 devdtr_init(void *dummy __unused)
1232 {
1233
1234 TASK_INIT(&dev_dtr_task, 0, destroy_dev_tq, NULL);
1235 }
1236
1237 SYSINIT(devdtr, SI_SUB_DEVFS, SI_ORDER_SECOND, devdtr_init, NULL);
1238
1239 #include "opt_ddb.h"
1240 #ifdef DDB
1241 #include <sys/kernel.h>
1242
1243 #include <ddb/ddb.h>
1244
1245 DB_SHOW_COMMAND(cdev, db_show_cdev)
1246 {
1247 struct cdev_priv *cdp;
1248 struct cdev *dev;
1249 u_int flags;
1250 char buf[512];
1251
1252 if (!have_addr) {
1253 TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
1254 dev = &cdp->cdp_c;
1255 db_printf("%s %p\n", dev->si_name, dev);
1256 if (db_pager_quit)
1257 break;
1258 }
1259 return;
1260 }
1261
1262 dev = (struct cdev *)addr;
1263 cdp = cdev2priv(dev);
1264 db_printf("dev %s ref %d use %ld thr %ld inuse %u fdpriv %p\n",
1265 dev->si_name, dev->si_refcount, dev->si_usecount,
1266 dev->si_threadcount, cdp->cdp_inuse, cdp->cdp_fdpriv.lh_first);
1267 db_printf("devsw %p si_drv0 %d si_drv1 %p si_drv2 %p\n",
1268 dev->si_devsw, dev->si_drv0, dev->si_drv1, dev->si_drv2);
1269 flags = dev->si_flags;
1270 #define SI_FLAG(flag) do { \
1271 if (flags & (flag)) { \
1272 if (buf[0] != '\0') \
1273 strlcat(buf, ", ", sizeof(buf)); \
1274 strlcat(buf, (#flag) + 3, sizeof(buf)); \
1275 flags &= ~(flag); \
1276 } \
1277 } while (0)
1278 buf[0] = '\0';
1279 SI_FLAG(SI_ETERNAL);
1280 SI_FLAG(SI_ALIAS);
1281 SI_FLAG(SI_NAMED);
1282 SI_FLAG(SI_CHEAPCLONE);
1283 SI_FLAG(SI_CHILD);
1284 SI_FLAG(SI_DEVOPEN);
1285 SI_FLAG(SI_CONSOPEN);
1286 SI_FLAG(SI_DUMPDEV);
1287 SI_FLAG(SI_CANDELETE);
1288 SI_FLAG(SI_CLONELIST);
1289 db_printf("si_flags %s\n", buf);
1290
1291 flags = cdp->cdp_flags;
1292 #define CDP_FLAG(flag) do { \
1293 if (flags & (flag)) { \
1294 if (buf[0] != '\0') \
1295 strlcat(buf, ", ", sizeof(buf)); \
1296 strlcat(buf, (#flag) + 4, sizeof(buf)); \
1297 flags &= ~(flag); \
1298 } \
1299 } while (0)
1300 buf[0] = '\0';
1301 CDP_FLAG(CDP_ACTIVE);
1302 CDP_FLAG(CDP_SCHED_DTR);
1303 db_printf("cdp_flags %s\n", buf);
1304 }
1305 #endif
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