1 /*
2 * Copyright (c) 2003 Matthew Dillon <dillon@backplane.com> All rights reserved.
3 * cdevsw from kern/kern_conf.c Copyright (c) 1995 Terrence R. Lambert
4 * cdevsw from kern/kern_conf.c Copyright (c) 1995 Julian R. Elischer,
5 * All rights reserved.
6 * Copyright (c) 1982, 1986, 1991, 1993
7 * The Regents of the University of California. All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <sys/param.h>
32 #include <sys/systm.h>
33 #include <sys/kernel.h>
34 #include <sys/sysctl.h>
35 #include <sys/module.h>
36 #include <sys/malloc.h>
37 #include <sys/conf.h>
38 #include <sys/bio.h>
39 #include <sys/buf.h>
40 #include <sys/vnode.h>
41 #include <sys/queue.h>
42 #include <sys/device.h>
43 #include <sys/tree.h>
44 #include <sys/syslink_rpc.h>
45 #include <sys/proc.h>
46 #include <sys/dsched.h>
47 #include <sys/devfs.h>
48 #include <sys/file.h>
49
50 #include <machine/stdarg.h>
51
52 #include <sys/mplock2.h>
53
54 /*
55 * system link descriptors identify the command in the
56 * arguments structure.
57 */
58 #define DDESCNAME(name) __CONCAT(__CONCAT(dev_,name),_desc)
59
60 #define DEVOP_DESC_INIT(name) \
61 struct syslink_desc DDESCNAME(name) = { \
62 __offsetof(struct dev_ops, __CONCAT(d_, name)), \
63 #name }
64
65 DEVOP_DESC_INIT(default);
66 DEVOP_DESC_INIT(open);
67 DEVOP_DESC_INIT(close);
68 DEVOP_DESC_INIT(read);
69 DEVOP_DESC_INIT(write);
70 DEVOP_DESC_INIT(ioctl);
71 DEVOP_DESC_INIT(dump);
72 DEVOP_DESC_INIT(psize);
73 DEVOP_DESC_INIT(mmap);
74 DEVOP_DESC_INIT(mmap_single);
75 DEVOP_DESC_INIT(strategy);
76 DEVOP_DESC_INIT(kqfilter);
77 DEVOP_DESC_INIT(revoke);
78 DEVOP_DESC_INIT(clone);
79
80 /*
81 * Misc default ops
82 */
83 struct dev_ops dead_dev_ops;
84
85 static d_open_t noopen;
86 static d_close_t noclose;
87 static d_read_t noread;
88 static d_write_t nowrite;
89 static d_ioctl_t noioctl;
90 static d_mmap_t nommap;
91 static d_mmap_single_t nommap_single;
92 static d_strategy_t nostrategy;
93 static d_dump_t nodump;
94 static d_psize_t nopsize;
95 static d_kqfilter_t nokqfilter;
96 static d_clone_t noclone;
97 static d_revoke_t norevoke;
98
99 struct dev_ops default_dev_ops = {
100 { "null" },
101 .d_default = NULL, /* must be NULL */
102 .d_open = noopen,
103 .d_close = noclose,
104 .d_read = noread,
105 .d_write = nowrite,
106 .d_ioctl = noioctl,
107 .d_mmap = nommap,
108 .d_mmap_single = nommap_single,
109 .d_strategy = nostrategy,
110 .d_dump = nodump,
111 .d_psize = nopsize,
112 .d_kqfilter = nokqfilter,
113 .d_revoke = norevoke,
114 .d_clone = noclone
115 };
116
117 static __inline
118 int
dev_needmplock(cdev_t dev)119 dev_needmplock(cdev_t dev)
120 {
121 return((dev->si_ops->head.flags & D_MPSAFE) == 0);
122 }
123
124 static __inline
125 int
dev_nokvabio(cdev_t dev)126 dev_nokvabio(cdev_t dev)
127 {
128 return((dev->si_ops->head.flags & D_KVABIO) == 0);
129 }
130
131 /************************************************************************
132 * GENERAL DEVICE API FUNCTIONS *
133 ************************************************************************
134 *
135 * The MPSAFEness of these depends on dev->si_ops->head.flags
136 */
137 int
dev_dopen(cdev_t dev,int oflags,int devtype,struct ucred * cred,struct file ** fpp,struct vnode * vp)138 dev_dopen(cdev_t dev, int oflags, int devtype, struct ucred *cred,
139 struct file **fpp, struct vnode *vp)
140 {
141 struct dev_open_args ap;
142 int needmplock = dev_needmplock(dev);
143 int error;
144
145 ap.a_head.a_desc = &dev_open_desc;
146 ap.a_head.a_dev = dev;
147 ap.a_oflags = oflags;
148 ap.a_devtype = devtype;
149 ap.a_cred = cred;
150 ap.a_fpp = fpp;
151 if (ap.a_fpp)
152 (*ap.a_fpp)->f_data = vp;
153
154 /*
155 * vref(vp) is being done in vop_stdopen()
156 *
157 * If a non-null vp is passed-in, the caller must also issue a
158 * vop_stdopen()
159 *
160 * NOTE: d_open() may replace *ap.a_fpp
161 */
162 if (needmplock)
163 get_mplock();
164 error = dev->si_ops->d_open(&ap);
165 if (needmplock)
166 rel_mplock();
167 return (error);
168 }
169
170 int
dev_dclose(cdev_t dev,int fflag,int devtype,struct file * fp)171 dev_dclose(cdev_t dev, int fflag, int devtype, struct file *fp)
172 {
173 struct dev_close_args ap;
174 int needmplock = dev_needmplock(dev);
175 int error;
176
177 ap.a_head.a_desc = &dev_close_desc;
178 ap.a_head.a_dev = dev;
179 ap.a_fflag = fflag;
180 ap.a_devtype = devtype;
181 ap.a_fp = fp;
182
183 if (needmplock)
184 get_mplock();
185 error = dev->si_ops->d_close(&ap);
186 if (needmplock)
187 rel_mplock();
188 return (error);
189 }
190
191 int
dev_dread(cdev_t dev,struct uio * uio,int ioflag,struct file * fp)192 dev_dread(cdev_t dev, struct uio *uio, int ioflag, struct file *fp)
193 {
194 struct dev_read_args ap;
195 int needmplock = dev_needmplock(dev);
196 int error;
197
198 ap.a_head.a_desc = &dev_read_desc;
199 ap.a_head.a_dev = dev;
200 ap.a_uio = uio;
201 ap.a_ioflag = ioflag;
202 ap.a_fp = fp;
203
204 if (needmplock)
205 get_mplock();
206 error = dev->si_ops->d_read(&ap);
207 if (needmplock)
208 rel_mplock();
209 if (error == 0)
210 dev->si_lastread = time_uptime;
211 return (error);
212 }
213
214 int
dev_dwrite(cdev_t dev,struct uio * uio,int ioflag,struct file * fp)215 dev_dwrite(cdev_t dev, struct uio *uio, int ioflag, struct file *fp)
216 {
217 struct dev_write_args ap;
218 int needmplock = dev_needmplock(dev);
219 int error;
220
221 dev->si_lastwrite = time_uptime;
222 ap.a_head.a_desc = &dev_write_desc;
223 ap.a_head.a_dev = dev;
224 ap.a_uio = uio;
225 ap.a_ioflag = ioflag;
226 ap.a_fp = fp;
227
228 if (needmplock)
229 get_mplock();
230 error = dev->si_ops->d_write(&ap);
231 if (needmplock)
232 rel_mplock();
233 return (error);
234 }
235
236 int
dev_dioctl(cdev_t dev,u_long cmd,caddr_t data,int fflag,struct ucred * cred,struct sysmsg * msg,struct file * fp)237 dev_dioctl(cdev_t dev, u_long cmd, caddr_t data, int fflag, struct ucred *cred,
238 struct sysmsg *msg, struct file *fp)
239 {
240 struct dev_ioctl_args ap;
241 int needmplock = dev_needmplock(dev);
242 int error;
243
244 ap.a_head.a_desc = &dev_ioctl_desc;
245 ap.a_head.a_dev = dev;
246 ap.a_cmd = cmd;
247 ap.a_data = data;
248 ap.a_fflag = fflag;
249 ap.a_cred = cred;
250 ap.a_sysmsg = msg;
251 ap.a_fp = fp;
252
253 if (needmplock)
254 get_mplock();
255 error = dev->si_ops->d_ioctl(&ap);
256 if (needmplock)
257 rel_mplock();
258 return (error);
259 }
260
261 int64_t
dev_dmmap(cdev_t dev,vm_offset_t offset,int nprot,struct file * fp)262 dev_dmmap(cdev_t dev, vm_offset_t offset, int nprot, struct file *fp)
263 {
264 struct dev_mmap_args ap;
265 int needmplock = dev_needmplock(dev);
266 int error;
267
268 ap.a_head.a_desc = &dev_mmap_desc;
269 ap.a_head.a_dev = dev;
270 ap.a_offset = offset;
271 ap.a_nprot = nprot;
272 ap.a_fp = fp;
273
274 if (needmplock)
275 get_mplock();
276 error = dev->si_ops->d_mmap(&ap);
277 if (needmplock)
278 rel_mplock();
279
280 if (error == 0)
281 return(ap.a_result);
282 return(-1);
283 }
284
285 int
dev_dmmap_single(cdev_t dev,vm_ooffset_t * offset,vm_size_t size,struct vm_object ** object,int nprot,struct file * fp)286 dev_dmmap_single(cdev_t dev, vm_ooffset_t *offset, vm_size_t size,
287 struct vm_object **object, int nprot, struct file *fp)
288 {
289 struct dev_mmap_single_args ap;
290 int needmplock = dev_needmplock(dev);
291 int error;
292
293 ap.a_head.a_desc = &dev_mmap_single_desc;
294 ap.a_head.a_dev = dev;
295 ap.a_offset = offset;
296 ap.a_size = size;
297 ap.a_object = object;
298 ap.a_nprot = nprot;
299 ap.a_fp = fp;
300
301 if (needmplock)
302 get_mplock();
303 error = dev->si_ops->d_mmap_single(&ap);
304 if (needmplock)
305 rel_mplock();
306
307 return(error);
308 }
309
310 int
dev_dclone(cdev_t dev)311 dev_dclone(cdev_t dev)
312 {
313 struct dev_clone_args ap;
314 int needmplock = dev_needmplock(dev);
315 int error;
316
317 ap.a_head.a_desc = &dev_clone_desc;
318 ap.a_head.a_dev = dev;
319
320 if (needmplock)
321 get_mplock();
322 error = dev->si_ops->d_clone(&ap);
323 if (needmplock)
324 rel_mplock();
325 return (error);
326 }
327
328 int
dev_drevoke(cdev_t dev)329 dev_drevoke(cdev_t dev)
330 {
331 struct dev_revoke_args ap;
332 int needmplock = dev_needmplock(dev);
333 int error;
334
335 ap.a_head.a_desc = &dev_revoke_desc;
336 ap.a_head.a_dev = dev;
337
338 if (needmplock)
339 get_mplock();
340 error = dev->si_ops->d_revoke(&ap);
341 if (needmplock)
342 rel_mplock();
343
344 return (error);
345 }
346
347 /*
348 * Core device strategy call, used to issue I/O on a device. There are
349 * two versions, a non-chained version and a chained version. The chained
350 * version reuses a BIO set up by vn_strategy(). The only difference is
351 * that, for now, we do not push a new tracking structure when chaining
352 * from vn_strategy. XXX this will ultimately have to change.
353 */
354 void
dev_dstrategy(cdev_t dev,struct bio * bio)355 dev_dstrategy(cdev_t dev, struct bio *bio)
356 {
357 struct dev_strategy_args ap;
358 struct bio_track *track;
359 struct buf *bp = bio->bio_buf;
360 int needmplock = dev_needmplock(dev);
361
362 /*
363 * If the device doe snot support KVABIO and the buffer is using
364 * KVABIO, we must synchronize b_data to all cpus before dispatching.
365 */
366 if (dev_nokvabio(dev) && (bp->b_flags & B_KVABIO))
367 bkvasync_all(bp);
368
369 ap.a_head.a_desc = &dev_strategy_desc;
370 ap.a_head.a_dev = dev;
371 ap.a_bio = bio;
372
373 KKASSERT(bio->bio_track == NULL);
374 KKASSERT(bp->b_cmd != BUF_CMD_DONE);
375 if (bp->b_cmd == BUF_CMD_READ)
376 track = &dev->si_track_read;
377 else
378 track = &dev->si_track_write;
379 bio_track_ref(track);
380 bio->bio_track = track;
381 dsched_buf_enter(bp); /* might stack */
382
383 KKASSERT((bio->bio_flags & BIO_DONE) == 0);
384 if (needmplock)
385 get_mplock();
386 (void)dev->si_ops->d_strategy(&ap);
387 if (needmplock)
388 rel_mplock();
389 }
390
391 void
dev_dstrategy_chain(cdev_t dev,struct bio * bio)392 dev_dstrategy_chain(cdev_t dev, struct bio *bio)
393 {
394 struct dev_strategy_args ap;
395 struct buf *bp = bio->bio_buf;
396 int needmplock = dev_needmplock(dev);
397
398 /*
399 * If the device doe snot support KVABIO and the buffer is using
400 * KVABIO, we must synchronize b_data to all cpus before dispatching.
401 */
402 if (dev_nokvabio(dev) && (bp->b_flags & B_KVABIO))
403 bkvasync_all(bp);
404
405 ap.a_head.a_desc = &dev_strategy_desc;
406 ap.a_head.a_dev = dev;
407 ap.a_bio = bio;
408
409 KKASSERT(bio->bio_track != NULL);
410 KKASSERT((bio->bio_flags & BIO_DONE) == 0);
411 if (needmplock)
412 get_mplock();
413 (void)dev->si_ops->d_strategy(&ap);
414 if (needmplock)
415 rel_mplock();
416 }
417
418 /*
419 * note: the disk layer is expected to set count, blkno, and secsize before
420 * forwarding the message.
421 */
422 int
dev_ddump(cdev_t dev,void * virtual,vm_offset_t physical,off_t offset,size_t length)423 dev_ddump(cdev_t dev, void *virtual, vm_offset_t physical, off_t offset,
424 size_t length)
425 {
426 struct dev_dump_args ap;
427 int needmplock = dev_needmplock(dev);
428 int error;
429
430 ap.a_head.a_desc = &dev_dump_desc;
431 ap.a_head.a_dev = dev;
432 ap.a_count = 0;
433 ap.a_blkno = 0;
434 ap.a_secsize = 0;
435 ap.a_virtual = virtual;
436 ap.a_physical = physical;
437 ap.a_offset = offset;
438 ap.a_length = length;
439
440 if (needmplock)
441 get_mplock();
442 error = dev->si_ops->d_dump(&ap);
443 if (needmplock)
444 rel_mplock();
445 return (error);
446 }
447
448 int64_t
dev_dpsize(cdev_t dev)449 dev_dpsize(cdev_t dev)
450 {
451 struct dev_psize_args ap;
452 int needmplock = dev_needmplock(dev);
453 int error;
454
455 ap.a_head.a_desc = &dev_psize_desc;
456 ap.a_head.a_dev = dev;
457
458 if (needmplock)
459 get_mplock();
460 error = dev->si_ops->d_psize(&ap);
461 if (needmplock)
462 rel_mplock();
463
464 if (error == 0)
465 return (ap.a_result);
466 return(-1);
467 }
468
469 /*
470 * Pass-thru to the device kqfilter.
471 *
472 * NOTE: We explicitly preset a_result to 0 so d_kqfilter() functions
473 * which return 0 do not have to bother setting a_result.
474 */
475 int
dev_dkqfilter(cdev_t dev,struct knote * kn,struct file * fp)476 dev_dkqfilter(cdev_t dev, struct knote *kn, struct file *fp)
477 {
478 struct dev_kqfilter_args ap;
479 int needmplock = dev_needmplock(dev);
480 int error;
481
482 ap.a_head.a_desc = &dev_kqfilter_desc;
483 ap.a_head.a_dev = dev;
484 ap.a_kn = kn;
485 ap.a_result = 0;
486 ap.a_fp = fp;
487
488 if (needmplock)
489 get_mplock();
490 error = dev->si_ops->d_kqfilter(&ap);
491 if (needmplock)
492 rel_mplock();
493
494 if (error == 0)
495 return(ap.a_result);
496 return(ENODEV);
497 }
498
499 /************************************************************************
500 * DEVICE HELPER FUNCTIONS *
501 ************************************************************************/
502
503 /*
504 * MPSAFE
505 */
506 int
dev_drefs(cdev_t dev)507 dev_drefs(cdev_t dev)
508 {
509 return(dev->si_sysref.refcnt);
510 }
511
512 /*
513 * MPSAFE
514 */
515 const char *
dev_dname(cdev_t dev)516 dev_dname(cdev_t dev)
517 {
518 return(dev->si_ops->head.name);
519 }
520
521 /*
522 * MPSAFE
523 */
524 int
dev_dflags(cdev_t dev)525 dev_dflags(cdev_t dev)
526 {
527 return(dev->si_ops->head.flags);
528 }
529
530 /*
531 * MPSAFE
532 */
533 int
dev_dmaj(cdev_t dev)534 dev_dmaj(cdev_t dev)
535 {
536 return(dev->si_ops->head.maj);
537 }
538
539 /*
540 * Used when forwarding a request through layers. The caller adjusts
541 * ap->a_head.a_dev and then calls this function.
542 */
543 int
dev_doperate(struct dev_generic_args * ap)544 dev_doperate(struct dev_generic_args *ap)
545 {
546 int (*func)(struct dev_generic_args *);
547 int needmplock = dev_needmplock(ap->a_dev);
548 int error;
549
550 func = *(void **)((char *)ap->a_dev->si_ops + ap->a_desc->sd_offset);
551
552 if (needmplock)
553 get_mplock();
554 error = func(ap);
555 if (needmplock)
556 rel_mplock();
557
558 return (error);
559 }
560
561 /*
562 * Used by the console intercept code only. Issue an operation through
563 * a foreign ops structure allowing the ops structure associated
564 * with the device to remain intact.
565 */
566 int
dev_doperate_ops(struct dev_ops * ops,struct dev_generic_args * ap)567 dev_doperate_ops(struct dev_ops *ops, struct dev_generic_args *ap)
568 {
569 int (*func)(struct dev_generic_args *);
570 int needmplock = ((ops->head.flags & D_MPSAFE) == 0);
571 int error;
572
573 func = *(void **)((char *)ops + ap->a_desc->sd_offset);
574
575 if (needmplock)
576 get_mplock();
577 error = func(ap);
578 if (needmplock)
579 rel_mplock();
580
581 return (error);
582 }
583
584 /*
585 * Convert a template dev_ops into the real thing by filling in
586 * uninitialized fields.
587 */
588 void
compile_dev_ops(struct dev_ops * ops)589 compile_dev_ops(struct dev_ops *ops)
590 {
591 int offset;
592
593 for (offset = offsetof(struct dev_ops, dev_ops_first_field);
594 offset <= offsetof(struct dev_ops, dev_ops_last_field);
595 offset += sizeof(void *)
596 ) {
597 void **func_p = (void **)((char *)ops + offset);
598 void **def_p = (void **)((char *)&default_dev_ops + offset);
599 if (*func_p == NULL) {
600 if (ops->d_default)
601 *func_p = ops->d_default;
602 else
603 *func_p = *def_p;
604 }
605 }
606 }
607
608 /************************************************************************
609 * MAJOR/MINOR SPACE FUNCTION *
610 ************************************************************************/
611
612 /*
613 * This makes a dev_ops entry visible to userland (e.g /dev/<blah>).
614 *
615 * Disk devices typically register their major, e.g. 'ad0', and then call
616 * into the disk label management code which overloads its own onto e.g. 'ad0'
617 * to support all the various slice and partition combinations.
618 *
619 * The mask/match supplied in this call are a full 32 bits and the same
620 * mask and match must be specified in a later dev_ops_remove() call to
621 * match this add. However, the match value for the minor number should never
622 * have any bits set in the major number's bit range (8-15). The mask value
623 * may be conveniently specified as -1 without creating any major number
624 * interference.
625 */
626
627 static
628 int
rb_dev_ops_compare(struct dev_ops_maj * a,struct dev_ops_maj * b)629 rb_dev_ops_compare(struct dev_ops_maj *a, struct dev_ops_maj *b)
630 {
631 if (a->maj < b->maj)
632 return(-1);
633 else if (a->maj > b->maj)
634 return(1);
635 return(0);
636 }
637
638 RB_GENERATE2(dev_ops_rb_tree, dev_ops_maj, rbnode, rb_dev_ops_compare, int, maj);
639
640 struct dev_ops_rb_tree dev_ops_rbhead = RB_INITIALIZER(dev_ops_rbhead);
641
642 int
dev_ops_remove_all(struct dev_ops * ops)643 dev_ops_remove_all(struct dev_ops *ops)
644 {
645 return devfs_destroy_dev_by_ops(ops, -1);
646 }
647
648 int
dev_ops_remove_minor(struct dev_ops * ops,int minor)649 dev_ops_remove_minor(struct dev_ops *ops, int minor)
650 {
651 return devfs_destroy_dev_by_ops(ops, minor);
652 }
653
654 struct dev_ops *
dev_ops_intercept(cdev_t dev,struct dev_ops * iops)655 dev_ops_intercept(cdev_t dev, struct dev_ops *iops)
656 {
657 struct dev_ops *oops = dev->si_ops;
658
659 compile_dev_ops(iops);
660 iops->head.maj = oops->head.maj;
661 iops->head.data = oops->head.data;
662 iops->head.flags = oops->head.flags;
663 dev->si_ops = iops;
664 dev->si_flags |= SI_INTERCEPTED;
665
666 return (oops);
667 }
668
669 void
dev_ops_restore(cdev_t dev,struct dev_ops * oops)670 dev_ops_restore(cdev_t dev, struct dev_ops *oops)
671 {
672 struct dev_ops *iops = dev->si_ops;
673
674 dev->si_ops = oops;
675 dev->si_flags &= ~SI_INTERCEPTED;
676 iops->head.maj = 0;
677 iops->head.data = NULL;
678 iops->head.flags = 0;
679 }
680
681 /************************************************************************
682 * DEFAULT DEV OPS FUNCTIONS *
683 ************************************************************************/
684
685
686 /*
687 * Unsupported devswitch functions (e.g. for writing to read-only device).
688 * XXX may belong elsewhere.
689 */
690 static int
norevoke(struct dev_revoke_args * ap)691 norevoke(struct dev_revoke_args *ap)
692 {
693 /* take no action */
694 return(0);
695 }
696
697 static int
noclone(struct dev_clone_args * ap)698 noclone(struct dev_clone_args *ap)
699 {
700 /* take no action */
701 return (0); /* allow the clone */
702 }
703
704 static int
noopen(struct dev_open_args * ap)705 noopen(struct dev_open_args *ap)
706 {
707 return (ENODEV);
708 }
709
710 static int
noclose(struct dev_close_args * ap)711 noclose(struct dev_close_args *ap)
712 {
713 return (ENODEV);
714 }
715
716 static int
noread(struct dev_read_args * ap)717 noread(struct dev_read_args *ap)
718 {
719 return (ENODEV);
720 }
721
722 static int
nowrite(struct dev_write_args * ap)723 nowrite(struct dev_write_args *ap)
724 {
725 return (ENODEV);
726 }
727
728 static int
noioctl(struct dev_ioctl_args * ap)729 noioctl(struct dev_ioctl_args *ap)
730 {
731 return (ENODEV);
732 }
733
734 static int
nokqfilter(struct dev_kqfilter_args * ap)735 nokqfilter(struct dev_kqfilter_args *ap)
736 {
737 return (ENODEV);
738 }
739
740 static int
nommap(struct dev_mmap_args * ap)741 nommap(struct dev_mmap_args *ap)
742 {
743 return (ENODEV);
744 }
745
746 static int
nommap_single(struct dev_mmap_single_args * ap)747 nommap_single(struct dev_mmap_single_args *ap)
748 {
749 return (ENODEV);
750 }
751
752 static int
nostrategy(struct dev_strategy_args * ap)753 nostrategy(struct dev_strategy_args *ap)
754 {
755 struct bio *bio = ap->a_bio;
756
757 bio->bio_buf->b_flags |= B_ERROR;
758 bio->bio_buf->b_error = EOPNOTSUPP;
759 biodone(bio);
760 return(0);
761 }
762
763 static int
nopsize(struct dev_psize_args * ap)764 nopsize(struct dev_psize_args *ap)
765 {
766 ap->a_result = 0;
767 return(0);
768 }
769
770 static int
nodump(struct dev_dump_args * ap)771 nodump(struct dev_dump_args *ap)
772 {
773 return (ENODEV);
774 }
775
776 /*
777 * XXX this is probably bogus. Any device that uses it isn't checking the
778 * minor number.
779 */
780 int
nullopen(struct dev_open_args * ap)781 nullopen(struct dev_open_args *ap)
782 {
783 return (0);
784 }
785
786 int
nullclose(struct dev_close_args * ap)787 nullclose(struct dev_close_args *ap)
788 {
789 return (0);
790 }
791