xref: /netbsd-src/sys/dev/ld.c (revision 001c68bd94f75ce9270b69227c4199fbf34ee396)
1 /*	$NetBSD: ld.c,v 1.26 2003/06/29 22:29:59 fvdl Exp $	*/
2 
3 /*-
4  * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Andrew Doran and Charles M. Hannum.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *        This product includes software developed by the NetBSD
21  *        Foundation, Inc. and its contributors.
22  * 4. Neither the name of The NetBSD Foundation nor the names of its
23  *    contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36  * POSSIBILITY OF SUCH DAMAGE.
37  */
38 
39 /*
40  * Disk driver for use by RAID controllers.
41  */
42 
43 #include <sys/cdefs.h>
44 __KERNEL_RCSID(0, "$NetBSD: ld.c,v 1.26 2003/06/29 22:29:59 fvdl Exp $");
45 
46 #include "rnd.h"
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/kernel.h>
51 #include <sys/device.h>
52 #include <sys/queue.h>
53 #include <sys/proc.h>
54 #include <sys/buf.h>
55 #include <sys/endian.h>
56 #include <sys/disklabel.h>
57 #include <sys/disk.h>
58 #include <sys/dkio.h>
59 #include <sys/stat.h>
60 #include <sys/lock.h>
61 #include <sys/conf.h>
62 #include <sys/fcntl.h>
63 #include <sys/vnode.h>
64 #include <sys/syslog.h>
65 #if NRND > 0
66 #include <sys/rnd.h>
67 #endif
68 
69 #include <dev/ldvar.h>
70 
71 static void	ldgetdefaultlabel(struct ld_softc *, struct disklabel *);
72 static void	ldgetdisklabel(struct ld_softc *);
73 static int	ldlock(struct ld_softc *);
74 static void	ldminphys(struct buf *bp);
75 static void	ldshutdown(void *);
76 static void	ldstart(struct ld_softc *);
77 static void	ldunlock(struct ld_softc *);
78 
79 extern struct	cfdriver ld_cd;
80 
81 dev_type_open(ldopen);
82 dev_type_close(ldclose);
83 dev_type_read(ldread);
84 dev_type_write(ldwrite);
85 dev_type_ioctl(ldioctl);
86 dev_type_strategy(ldstrategy);
87 dev_type_dump(lddump);
88 dev_type_size(ldsize);
89 
90 const struct bdevsw ld_bdevsw = {
91 	ldopen, ldclose, ldstrategy, ldioctl, lddump, ldsize, D_DISK
92 };
93 
94 const struct cdevsw ld_cdevsw = {
95 	ldopen, ldclose, ldread, ldwrite, ldioctl,
96 	nostop, notty, nopoll, nommap, nokqfilter, D_DISK
97 };
98 
99 static struct	dkdriver lddkdriver = { ldstrategy };
100 static void	*ld_sdh;
101 
102 void
103 ldattach(struct ld_softc *sc)
104 {
105 	char buf[9];
106 
107 	if ((sc->sc_flags & LDF_ENABLED) == 0) {
108 		printf("%s: disabled\n", sc->sc_dv.dv_xname);
109 		return;
110 	}
111 
112 	/* Initialise and attach the disk structure. */
113 	sc->sc_dk.dk_driver = &lddkdriver;
114 	sc->sc_dk.dk_name = sc->sc_dv.dv_xname;
115 	disk_attach(&sc->sc_dk);
116 
117 	if (sc->sc_maxxfer > MAXPHYS)
118 		sc->sc_maxxfer = MAXPHYS;
119 
120 	/* Build synthetic geometry if necessary. */
121 	if (sc->sc_nheads == 0 || sc->sc_nsectors == 0 ||
122 	    sc->sc_ncylinders == 0) {
123 		if (sc->sc_secperunit <= 528 * 2048)		/* 528MB */
124 			sc->sc_nheads = 16;
125 		else if (sc->sc_secperunit <= 1024 * 2048)	/* 1GB */
126 			sc->sc_nheads = 32;
127 		else if (sc->sc_secperunit <= 21504 * 2048)	/* 21GB */
128 			sc->sc_nheads = 64;
129 		else if (sc->sc_secperunit <= 43008 * 2048)	/* 42GB */
130 			sc->sc_nheads = 128;
131 		else
132 			sc->sc_nheads = 255;
133 
134 		sc->sc_nsectors = 63;
135 		sc->sc_ncylinders = sc->sc_secperunit /
136 		    (sc->sc_nheads * sc->sc_nsectors);
137 	}
138 
139 	format_bytes(buf, sizeof(buf), (u_int64_t)sc->sc_secperunit *
140 	    sc->sc_secsize);
141 	printf("%s: %s, %d cyl, %d head, %d sec, %d bytes/sect x %d sectors\n",
142 	    sc->sc_dv.dv_xname, buf, sc->sc_ncylinders, sc->sc_nheads,
143 	    sc->sc_nsectors, sc->sc_secsize, sc->sc_secperunit);
144 
145 #if NRND > 0
146 	/* Attach the device into the rnd source list. */
147 	rnd_attach_source(&sc->sc_rnd_source, sc->sc_dv.dv_xname,
148 	    RND_TYPE_DISK, 0);
149 #endif
150 
151 	/* Set the `shutdownhook'. */
152 	if (ld_sdh == NULL)
153 		ld_sdh = shutdownhook_establish(ldshutdown, NULL);
154 	bufq_alloc(&sc->sc_bufq, BUFQ_FCFS);
155 }
156 
157 int
158 ldadjqparam(struct ld_softc *sc, int max)
159 {
160 	int s;
161 
162 	s = splbio();
163 	sc->sc_maxqueuecnt = max;
164 	splx(s);
165 
166 	return (0);
167 }
168 
169 int
170 ldbegindetach(struct ld_softc *sc, int flags)
171 {
172 	int s, rv = 0;
173 
174 	if ((sc->sc_flags & LDF_ENABLED) == 0)
175 		return (0);
176 
177 	if ((flags & DETACH_FORCE) == 0 && sc->sc_dk.dk_openmask != 0)
178 		return (EBUSY);
179 
180 	s = splbio();
181 	sc->sc_maxqueuecnt = 0;
182 	sc->sc_flags |= LDF_DETACH;
183 	while (sc->sc_queuecnt > 0) {
184 		sc->sc_flags |= LDF_DRAIN;
185 		rv = tsleep(&sc->sc_queuecnt, PRIBIO, "lddrn", 0);
186 		if (rv)
187 			break;
188 	}
189 	splx(s);
190 
191 	return (rv);
192 }
193 
194 void
195 ldenddetach(struct ld_softc *sc)
196 {
197 	struct buf *bp;
198 	int s, bmaj, cmaj, i, mn;
199 
200 	if ((sc->sc_flags & LDF_ENABLED) == 0)
201 		return;
202 
203 	/* Wait for commands queued with the hardware to complete. */
204 	if (sc->sc_queuecnt != 0)
205 		if (tsleep(&sc->sc_queuecnt, PRIBIO, "lddtch", 30 * hz))
206 			printf("%s: not drained\n", sc->sc_dv.dv_xname);
207 
208 	/* Locate the major numbers. */
209 	bmaj = bdevsw_lookup_major(&ld_bdevsw);
210 	cmaj = cdevsw_lookup_major(&ld_cdevsw);
211 
212 	/* Kill off any queued buffers. */
213 	s = splbio();
214 	while ((bp = BUFQ_GET(&sc->sc_bufq)) != NULL) {
215 		bp->b_error = EIO;
216 		bp->b_flags |= B_ERROR;
217 		bp->b_resid = bp->b_bcount;
218 		biodone(bp);
219 	}
220 	bufq_free(&sc->sc_bufq);
221 	splx(s);
222 
223 	/* Nuke the vnodes for any open instances. */
224 	for (i = 0; i < MAXPARTITIONS; i++) {
225 		mn = DISKMINOR(sc->sc_dv.dv_unit, i);
226 		vdevgone(bmaj, mn, mn, VBLK);
227 		vdevgone(cmaj, mn, mn, VCHR);
228 	}
229 
230 	/* Detach from the disk list. */
231 	disk_detach(&sc->sc_dk);
232 
233 #if NRND > 0
234 	/* Unhook the entropy source. */
235 	rnd_detach_source(&sc->sc_rnd_source);
236 #endif
237 
238 	/*
239 	 * XXX We can't really flush the cache here, beceause the
240 	 * XXX device may already be non-existent from the controller's
241 	 * XXX perspective.
242 	 */
243 #if 0
244 	/* Flush the device's cache. */
245 	if (sc->sc_flush != NULL)
246 		if ((*sc->sc_flush)(sc) != 0)
247 			printf("%s: unable to flush cache\n",
248 			    sc->sc_dv.dv_xname);
249 #endif
250 }
251 
252 /* ARGSUSED */
253 static void
254 ldshutdown(void *cookie)
255 {
256 	struct ld_softc *sc;
257 	int i;
258 
259 	for (i = 0; i < ld_cd.cd_ndevs; i++) {
260 		if ((sc = device_lookup(&ld_cd, i)) == NULL)
261 			continue;
262 		if (sc->sc_flush != NULL && (*sc->sc_flush)(sc) != 0)
263 			printf("%s: unable to flush cache\n",
264 			    sc->sc_dv.dv_xname);
265 	}
266 }
267 
268 /* ARGSUSED */
269 int
270 ldopen(dev_t dev, int flags, int fmt, struct proc *p)
271 {
272 	struct ld_softc *sc;
273 	int unit, part;
274 
275 	unit = DISKUNIT(dev);
276 	if ((sc = device_lookup(&ld_cd, unit))== NULL)
277 		return (ENXIO);
278 	if ((sc->sc_flags & LDF_ENABLED) == 0)
279 		return (ENODEV);
280 	part = DISKPART(dev);
281 	ldlock(sc);
282 
283 	if (sc->sc_dk.dk_openmask == 0) {
284 		/* Load the partition info if not already loaded. */
285 		if ((sc->sc_flags & LDF_VLABEL) == 0)
286 			ldgetdisklabel(sc);
287 	}
288 
289 	/* Check that the partition exists. */
290 	if (part != RAW_PART && (part >= sc->sc_dk.dk_label->d_npartitions ||
291 	    sc->sc_dk.dk_label->d_partitions[part].p_fstype == FS_UNUSED)) {
292 	     	ldunlock(sc);
293 		return (ENXIO);
294 	}
295 
296 	/* Ensure only one open at a time. */
297 	switch (fmt) {
298 	case S_IFCHR:
299 		sc->sc_dk.dk_copenmask |= (1 << part);
300 		break;
301 	case S_IFBLK:
302 		sc->sc_dk.dk_bopenmask |= (1 << part);
303 		break;
304 	}
305 	sc->sc_dk.dk_openmask =
306 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
307 
308 	ldunlock(sc);
309 	return (0);
310 }
311 
312 /* ARGSUSED */
313 int
314 ldclose(dev_t dev, int flags, int fmt, struct proc *p)
315 {
316 	struct ld_softc *sc;
317 	int part, unit;
318 
319 	unit = DISKUNIT(dev);
320 	part = DISKPART(dev);
321 	sc = device_lookup(&ld_cd, unit);
322 	ldlock(sc);
323 
324 	switch (fmt) {
325 	case S_IFCHR:
326 		sc->sc_dk.dk_copenmask &= ~(1 << part);
327 		break;
328 	case S_IFBLK:
329 		sc->sc_dk.dk_bopenmask &= ~(1 << part);
330 		break;
331 	}
332 	sc->sc_dk.dk_openmask =
333 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
334 
335 	if (sc->sc_dk.dk_openmask == 0) {
336 		if (sc->sc_flush != NULL && (*sc->sc_flush)(sc) != 0)
337 			printf("%s: unable to flush cache\n",
338 			    sc->sc_dv.dv_xname);
339 		if ((sc->sc_flags & LDF_KLABEL) == 0)
340 			sc->sc_flags &= ~LDF_VLABEL;
341 	}
342 
343 	ldunlock(sc);
344 	return (0);
345 }
346 
347 /* ARGSUSED */
348 int
349 ldread(dev_t dev, struct uio *uio, int ioflag)
350 {
351 
352 	return (physio(ldstrategy, NULL, dev, B_READ, ldminphys, uio));
353 }
354 
355 /* ARGSUSED */
356 int
357 ldwrite(dev_t dev, struct uio *uio, int ioflag)
358 {
359 
360 	return (physio(ldstrategy, NULL, dev, B_WRITE, ldminphys, uio));
361 }
362 
363 /* ARGSUSED */
364 int
365 ldioctl(dev_t dev, u_long cmd, caddr_t addr, int32_t flag, struct proc *p)
366 {
367 	struct ld_softc *sc;
368 	int part, unit, error;
369 #ifdef __HAVE_OLD_DISKLABEL
370 	struct disklabel newlabel;
371 #endif
372 	struct disklabel *lp;
373 
374 	unit = DISKUNIT(dev);
375 	part = DISKPART(dev);
376 	sc = device_lookup(&ld_cd, unit);
377 	error = 0;
378 
379 	switch (cmd) {
380 	case DIOCGDINFO:
381 		memcpy(addr, sc->sc_dk.dk_label, sizeof(struct disklabel));
382 		return (0);
383 
384 #ifdef __HAVE_OLD_DISKLABEL
385 	case ODIOCGDINFO:
386 		newlabel = *(sc->sc_dk.dk_label);
387 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
388 			return ENOTTY;
389 		memcpy(addr, &newlabel, sizeof(struct olddisklabel));
390 		return (0);
391 #endif
392 
393 	case DIOCGPART:
394 		((struct partinfo *)addr)->disklab = sc->sc_dk.dk_label;
395 		((struct partinfo *)addr)->part =
396 		    &sc->sc_dk.dk_label->d_partitions[part];
397 		break;
398 
399 	case DIOCWDINFO:
400 	case DIOCSDINFO:
401 #ifdef __HAVE_OLD_DISKLABEL
402 	case ODIOCWDINFO:
403 	case ODIOCSDINFO:
404 
405 		if (cmd == ODIOCSDINFO || cmd == ODIOCWDINFO) {
406 			memset(&newlabel, 0, sizeof newlabel);
407 			memcpy(&newlabel, addr, sizeof (struct olddisklabel));
408 			lp = &newlabel;
409 		} else
410 #endif
411 		lp = (struct disklabel *)addr;
412 
413 		if ((flag & FWRITE) == 0)
414 			return (EBADF);
415 
416 		if ((error = ldlock(sc)) != 0)
417 			return (error);
418 		sc->sc_flags |= LDF_LABELLING;
419 
420 		error = setdisklabel(sc->sc_dk.dk_label,
421 		    lp, /*sc->sc_dk.dk_openmask : */0,
422 		    sc->sc_dk.dk_cpulabel);
423 		if (error == 0 && (cmd == DIOCWDINFO
424 #ifdef __HAVE_OLD_DISKLABEL
425 		    || cmd == ODIOCWDINFO
426 #endif
427 		    ))
428 			error = writedisklabel(
429 			    MAKEDISKDEV(major(dev), DISKUNIT(dev), RAW_PART),
430 			    ldstrategy, sc->sc_dk.dk_label,
431 			    sc->sc_dk.dk_cpulabel);
432 
433 		sc->sc_flags &= ~LDF_LABELLING;
434 		ldunlock(sc);
435 		break;
436 
437 	case DIOCKLABEL:
438 		if ((flag & FWRITE) == 0)
439 			return (EBADF);
440 		if (*(int *)addr)
441 			sc->sc_flags |= LDF_KLABEL;
442 		else
443 			sc->sc_flags &= ~LDF_KLABEL;
444 		break;
445 
446 	case DIOCWLABEL:
447 		if ((flag & FWRITE) == 0)
448 			return (EBADF);
449 		if (*(int *)addr)
450 			sc->sc_flags |= LDF_WLABEL;
451 		else
452 			sc->sc_flags &= ~LDF_WLABEL;
453 		break;
454 
455 	case DIOCGDEFLABEL:
456 		ldgetdefaultlabel(sc, (struct disklabel *)addr);
457 		break;
458 
459 #ifdef __HAVE_OLD_DISKLABEL
460 	case ODIOCGDEFLABEL:
461 		ldgetdefaultlabel(sc, &newlabel);
462 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
463 			return ENOTTY;
464 		memcpy(addr, &newlabel, sizeof (struct olddisklabel));
465 		break;
466 #endif
467 
468 	default:
469 		error = ENOTTY;
470 		break;
471 	}
472 
473 	return (error);
474 }
475 
476 void
477 ldstrategy(struct buf *bp)
478 {
479 	struct ld_softc *sc;
480 	struct disklabel *lp;
481 	daddr_t blkno;
482 	int s, part;
483 
484 	sc = device_lookup(&ld_cd, DISKUNIT(bp->b_dev));
485 	part = DISKPART(bp->b_dev);
486 
487 	if ((sc->sc_flags & LDF_DETACH) != 0) {
488 		bp->b_error = EIO;
489 		goto bad;
490 	}
491 
492 	lp = sc->sc_dk.dk_label;
493 
494 	/*
495 	 * The transfer must be a whole number of blocks and the offset must
496 	 * not be negative.
497 	 */
498 	if ((bp->b_bcount % lp->d_secsize) != 0 || bp->b_blkno < 0) {
499 		bp->b_error = EINVAL;
500 		goto bad;
501 	}
502 
503 	/* If it's a null transfer, return immediately. */
504 	if (bp->b_bcount == 0)
505 		goto done;
506 
507 	/*
508 	 * Do bounds checking and adjust the transfer.  If error, process.
509 	 * If past the end of partition, just return.
510 	 */
511 	if (part != RAW_PART &&
512 	    bounds_check_with_label(&sc->sc_dk, bp,
513 	    (sc->sc_flags & (LDF_WLABEL | LDF_LABELLING)) != 0) <= 0) {
514 		goto done;
515 	}
516 
517 	/*
518 	 * Convert the block number to absolute and put it in terms
519 	 * of the device's logical block size.
520 	 */
521 	if (lp->d_secsize == DEV_BSIZE)
522 		blkno = bp->b_blkno;
523 	else if (lp->d_secsize > DEV_BSIZE)
524 		blkno = bp->b_blkno / (lp->d_secsize / DEV_BSIZE);
525 	else
526 		blkno = bp->b_blkno * (DEV_BSIZE / lp->d_secsize);
527 
528 	if (part != RAW_PART)
529 		blkno += lp->d_partitions[part].p_offset;
530 
531 	bp->b_rawblkno = blkno;
532 
533 	s = splbio();
534 	BUFQ_PUT(&sc->sc_bufq, bp);
535 	ldstart(sc);
536 	splx(s);
537 	return;
538 
539  bad:
540 	bp->b_flags |= B_ERROR;
541  done:
542 	bp->b_resid = bp->b_bcount;
543 	biodone(bp);
544 }
545 
546 static void
547 ldstart(struct ld_softc *sc)
548 {
549 	struct buf *bp;
550 	int error;
551 
552 	while (sc->sc_queuecnt < sc->sc_maxqueuecnt) {
553 		/* See if there is work to do. */
554 		if ((bp = BUFQ_PEEK(&sc->sc_bufq)) == NULL)
555 			break;
556 
557 		disk_busy(&sc->sc_dk);
558 		sc->sc_queuecnt++;
559 
560 		if (__predict_true((error = (*sc->sc_start)(sc, bp)) == 0)) {
561 			/*
562 			 * The back-end is running the job; remove it from
563 			 * the queue.
564 			 */
565 			(void) BUFQ_GET(&sc->sc_bufq);
566 		} else  {
567 			disk_unbusy(&sc->sc_dk, 0, (bp->b_flags & B_READ));
568 			sc->sc_queuecnt--;
569 			if (error == EAGAIN) {
570 				/*
571 				 * Temporary resource shortage in the
572 				 * back-end; just defer the job until
573 				 * later.
574 				 *
575 				 * XXX We might consider a watchdog timer
576 				 * XXX to make sure we are kicked into action.
577 				 */
578 				break;
579 			} else {
580 				(void) BUFQ_GET(&sc->sc_bufq);
581 				bp->b_error = error;
582 				bp->b_flags |= B_ERROR;
583 				bp->b_resid = bp->b_bcount;
584 				biodone(bp);
585 			}
586 		}
587 	}
588 }
589 
590 void
591 lddone(struct ld_softc *sc, struct buf *bp)
592 {
593 
594 	if ((bp->b_flags & B_ERROR) != 0) {
595 		diskerr(bp, "ld", "error", LOG_PRINTF, 0, sc->sc_dk.dk_label);
596 		printf("\n");
597 	}
598 
599 	disk_unbusy(&sc->sc_dk, bp->b_bcount - bp->b_resid,
600 	    (bp->b_flags & B_READ));
601 #if NRND > 0
602 	rnd_add_uint32(&sc->sc_rnd_source, bp->b_rawblkno);
603 #endif
604 	biodone(bp);
605 
606 	if (--sc->sc_queuecnt <= sc->sc_maxqueuecnt) {
607 		if ((sc->sc_flags & LDF_DRAIN) != 0) {
608 			sc->sc_flags &= ~LDF_DRAIN;
609 			wakeup(&sc->sc_queuecnt);
610 		}
611 		ldstart(sc);
612 	}
613 }
614 
615 int
616 ldsize(dev_t dev)
617 {
618 	struct ld_softc *sc;
619 	int part, unit, omask, size;
620 
621 	unit = DISKUNIT(dev);
622 	if ((sc = device_lookup(&ld_cd, unit)) == NULL)
623 		return (ENODEV);
624 	if ((sc->sc_flags & LDF_ENABLED) == 0)
625 		return (ENODEV);
626 	part = DISKPART(dev);
627 
628 	omask = sc->sc_dk.dk_openmask & (1 << part);
629 
630 	if (omask == 0 && ldopen(dev, 0, S_IFBLK, NULL) != 0)
631 		return (-1);
632 	else if (sc->sc_dk.dk_label->d_partitions[part].p_fstype != FS_SWAP)
633 		size = -1;
634 	else
635 		size = sc->sc_dk.dk_label->d_partitions[part].p_size *
636 		    (sc->sc_dk.dk_label->d_secsize / DEV_BSIZE);
637 	if (omask == 0 && ldclose(dev, 0, S_IFBLK, NULL) != 0)
638 		return (-1);
639 
640 	return (size);
641 }
642 
643 /*
644  * Load the label information from the specified device.
645  */
646 static void
647 ldgetdisklabel(struct ld_softc *sc)
648 {
649 	const char *errstring;
650 
651 	ldgetdefaultlabel(sc, sc->sc_dk.dk_label);
652 
653 	/* Call the generic disklabel extraction routine. */
654 	errstring = readdisklabel(MAKEDISKDEV(0, sc->sc_dv.dv_unit, RAW_PART),
655 	    ldstrategy, sc->sc_dk.dk_label, sc->sc_dk.dk_cpulabel);
656 	if (errstring != NULL)
657 		printf("%s: %s\n", sc->sc_dv.dv_xname, errstring);
658 
659 	/* In-core label now valid. */
660 	sc->sc_flags |= LDF_VLABEL;
661 }
662 
663 /*
664  * Construct a ficticious label.
665  */
666 static void
667 ldgetdefaultlabel(struct ld_softc *sc, struct disklabel *lp)
668 {
669 
670 	memset(lp, 0, sizeof(struct disklabel));
671 
672 	lp->d_secsize = sc->sc_secsize;
673 	lp->d_ntracks = sc->sc_nheads;
674 	lp->d_nsectors = sc->sc_nsectors;
675 	lp->d_ncylinders = sc->sc_ncylinders;
676 	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;
677 	lp->d_type = DTYPE_LD;
678 	strlcpy(lp->d_typename, "unknown", sizeof(lp->d_typename));
679 	strlcpy(lp->d_packname, "fictitious", sizeof(lp->d_packname));
680 	lp->d_secperunit = sc->sc_secperunit;
681 	lp->d_rpm = 7200;
682 	lp->d_interleave = 1;
683 	lp->d_flags = 0;
684 
685 	lp->d_partitions[RAW_PART].p_offset = 0;
686 	lp->d_partitions[RAW_PART].p_size =
687 	    lp->d_secperunit * (lp->d_secsize / DEV_BSIZE);
688 	lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
689 	lp->d_npartitions = RAW_PART + 1;
690 
691 	lp->d_magic = DISKMAGIC;
692 	lp->d_magic2 = DISKMAGIC;
693 	lp->d_checksum = dkcksum(lp);
694 }
695 
696 /*
697  * Wait interruptibly for an exclusive lock.
698  *
699  * XXX Several drivers do this; it should be abstracted and made MP-safe.
700  */
701 static int
702 ldlock(struct ld_softc *sc)
703 {
704 	int error;
705 
706 	while ((sc->sc_flags & LDF_LKHELD) != 0) {
707 		sc->sc_flags |= LDF_LKWANTED;
708 		if ((error = tsleep(sc, PRIBIO | PCATCH, "ldlck", 0)) != 0)
709 			return (error);
710 	}
711 	sc->sc_flags |= LDF_LKHELD;
712 	return (0);
713 }
714 
715 /*
716  * Unlock and wake up any waiters.
717  */
718 static void
719 ldunlock(struct ld_softc *sc)
720 {
721 
722 	sc->sc_flags &= ~LDF_LKHELD;
723 	if ((sc->sc_flags & LDF_LKWANTED) != 0) {
724 		sc->sc_flags &= ~LDF_LKWANTED;
725 		wakeup(sc);
726 	}
727 }
728 
729 /*
730  * Take a dump.
731  */
732 int
733 lddump(dev_t dev, daddr_t blkno, caddr_t va, size_t size)
734 {
735 	struct ld_softc *sc;
736 	struct disklabel *lp;
737 	int unit, part, nsects, sectoff, towrt, nblk, maxblkcnt, rv;
738 	static int dumping;
739 
740 	unit = DISKUNIT(dev);
741 	if ((sc = device_lookup(&ld_cd, unit)) == NULL)
742 		return (ENXIO);
743 	if ((sc->sc_flags & LDF_ENABLED) == 0)
744 		return (ENODEV);
745 	if (sc->sc_dump == NULL)
746 		return (ENXIO);
747 
748 	/* Check if recursive dump; if so, punt. */
749 	if (dumping)
750 		return (EFAULT);
751 	dumping = 1;
752 
753 	/* Convert to disk sectors.  Request must be a multiple of size. */
754 	part = DISKPART(dev);
755 	lp = sc->sc_dk.dk_label;
756 	if ((size % lp->d_secsize) != 0)
757 		return (EFAULT);
758 	towrt = size / lp->d_secsize;
759 	blkno = dbtob(blkno) / lp->d_secsize;	/* blkno in DEV_BSIZE units */
760 
761 	nsects = lp->d_partitions[part].p_size;
762 	sectoff = lp->d_partitions[part].p_offset;
763 
764 	/* Check transfer bounds against partition size. */
765 	if ((blkno < 0) || ((blkno + towrt) > nsects))
766 		return (EINVAL);
767 
768 	/* Offset block number to start of partition. */
769 	blkno += sectoff;
770 
771 	/* Start dumping and return when done. */
772 	maxblkcnt = sc->sc_maxxfer / sc->sc_secsize - 1;
773 	while (towrt > 0) {
774 		nblk = min(maxblkcnt, towrt);
775 
776 		if ((rv = (*sc->sc_dump)(sc, va, blkno, nblk)) != 0)
777 			return (rv);
778 
779 		towrt -= nblk;
780 		blkno += nblk;
781 		va += nblk * sc->sc_secsize;
782 	}
783 
784 	dumping = 0;
785 	return (0);
786 }
787 
788 /*
789  * Adjust the size of a transfer.
790  */
791 static void
792 ldminphys(struct buf *bp)
793 {
794 	struct ld_softc *sc;
795 
796 	sc = device_lookup(&ld_cd, DISKUNIT(bp->b_dev));
797 
798 	if (bp->b_bcount > sc->sc_maxxfer)
799 		bp->b_bcount = sc->sc_maxxfer;
800 	minphys(bp);
801 }
802