xref: /netbsd-src/sys/dev/ld.c (revision 23c8222edbfb0f0932d88a8351d3a0cf817dfb9e)
1 /*	$NetBSD: ld.c,v 1.33 2004/10/28 07:07:39 yamt 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 1.33 2004/10/28 07:07:39 yamt 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/bufq.h>
56 #include <sys/endian.h>
57 #include <sys/disklabel.h>
58 #include <sys/disk.h>
59 #include <sys/dkio.h>
60 #include <sys/stat.h>
61 #include <sys/lock.h>
62 #include <sys/conf.h>
63 #include <sys/fcntl.h>
64 #include <sys/vnode.h>
65 #include <sys/syslog.h>
66 #if NRND > 0
67 #include <sys/rnd.h>
68 #endif
69 
70 #include <dev/ldvar.h>
71 
72 static void	ldgetdefaultlabel(struct ld_softc *, struct disklabel *);
73 static void	ldgetdisklabel(struct ld_softc *);
74 static void	ldminphys(struct buf *bp);
75 static void	ldshutdown(void *);
76 static void	ldstart(struct ld_softc *);
77 
78 extern struct	cfdriver ld_cd;
79 
80 static dev_type_open(ldopen);
81 static dev_type_close(ldclose);
82 static dev_type_read(ldread);
83 static dev_type_write(ldwrite);
84 static dev_type_ioctl(ldioctl);
85 static dev_type_strategy(ldstrategy);
86 static dev_type_dump(lddump);
87 static dev_type_size(ldsize);
88 
89 const struct bdevsw ld_bdevsw = {
90 	ldopen, ldclose, ldstrategy, ldioctl, lddump, ldsize, D_DISK
91 };
92 
93 const struct cdevsw ld_cdevsw = {
94 	ldopen, ldclose, ldread, ldwrite, ldioctl,
95 	nostop, notty, nopoll, nommap, nokqfilter, D_DISK
96 };
97 
98 static struct	dkdriver lddkdriver = { ldstrategy, ldminphys };
99 static void	*ld_sdh;
100 
101 void
102 ldattach(struct ld_softc *sc)
103 {
104 	char buf[9];
105 
106 	if ((sc->sc_flags & LDF_ENABLED) == 0) {
107 		printf("%s: disabled\n", sc->sc_dv.dv_xname);
108 		return;
109 	}
110 
111 	/* Initialise and attach the disk structure. */
112 	sc->sc_dk.dk_driver = &lddkdriver;
113 	sc->sc_dk.dk_name = sc->sc_dv.dv_xname;
114 	disk_attach(&sc->sc_dk);
115 
116 	if (sc->sc_maxxfer > MAXPHYS)
117 		sc->sc_maxxfer = MAXPHYS;
118 
119 	/* Build synthetic geometry if necessary. */
120 	if (sc->sc_nheads == 0 || sc->sc_nsectors == 0 ||
121 	    sc->sc_ncylinders == 0) {
122 		uint64_t ncyl;
123 
124 		if (sc->sc_secperunit <= 528 * 2048)		/* 528MB */
125 			sc->sc_nheads = 16;
126 		else if (sc->sc_secperunit <= 1024 * 2048)	/* 1GB */
127 			sc->sc_nheads = 32;
128 		else if (sc->sc_secperunit <= 21504 * 2048)	/* 21GB */
129 			sc->sc_nheads = 64;
130 		else if (sc->sc_secperunit <= 43008 * 2048)	/* 42GB */
131 			sc->sc_nheads = 128;
132 		else
133 			sc->sc_nheads = 255;
134 
135 		sc->sc_nsectors = 63;
136 		sc->sc_ncylinders = INT_MAX;
137 		ncyl = sc->sc_secperunit /
138 		    (sc->sc_nheads * sc->sc_nsectors);
139 		if (ncyl < INT_MAX)
140 			sc->sc_ncylinders = (int)ncyl;
141 	}
142 
143 	format_bytes(buf, sizeof(buf), sc->sc_secperunit *
144 	    sc->sc_secsize);
145 	printf("%s: %s, %d cyl, %d head, %d sec, %d bytes/sect x %"PRIu64" sectors\n",
146 	    sc->sc_dv.dv_xname, buf, sc->sc_ncylinders, sc->sc_nheads,
147 	    sc->sc_nsectors, sc->sc_secsize, sc->sc_secperunit);
148 
149 #if NRND > 0
150 	/* Attach the device into the rnd source list. */
151 	rnd_attach_source(&sc->sc_rnd_source, sc->sc_dv.dv_xname,
152 	    RND_TYPE_DISK, 0);
153 #endif
154 
155 	/* Set the `shutdownhook'. */
156 	if (ld_sdh == NULL)
157 		ld_sdh = shutdownhook_establish(ldshutdown, NULL);
158 	bufq_alloc(&sc->sc_bufq, BUFQ_DISK_DEFAULT_STRAT()|BUFQ_SORT_RAWBLOCK);
159 
160 	/* Discover wedges on this disk. */
161 	dkwedge_discover(&sc->sc_dk);
162 }
163 
164 int
165 ldadjqparam(struct ld_softc *sc, int max)
166 {
167 	int s;
168 
169 	s = splbio();
170 	sc->sc_maxqueuecnt = max;
171 	splx(s);
172 
173 	return (0);
174 }
175 
176 int
177 ldbegindetach(struct ld_softc *sc, int flags)
178 {
179 	int s, rv = 0;
180 
181 	if ((sc->sc_flags & LDF_ENABLED) == 0)
182 		return (0);
183 
184 	if ((flags & DETACH_FORCE) == 0 && sc->sc_dk.dk_openmask != 0)
185 		return (EBUSY);
186 
187 	s = splbio();
188 	sc->sc_maxqueuecnt = 0;
189 	sc->sc_flags |= LDF_DETACH;
190 	while (sc->sc_queuecnt > 0) {
191 		sc->sc_flags |= LDF_DRAIN;
192 		rv = tsleep(&sc->sc_queuecnt, PRIBIO, "lddrn", 0);
193 		if (rv)
194 			break;
195 	}
196 	splx(s);
197 
198 	return (rv);
199 }
200 
201 void
202 ldenddetach(struct ld_softc *sc)
203 {
204 	struct buf *bp;
205 	int s, bmaj, cmaj, i, mn;
206 
207 	if ((sc->sc_flags & LDF_ENABLED) == 0)
208 		return;
209 
210 	/* Wait for commands queued with the hardware to complete. */
211 	if (sc->sc_queuecnt != 0)
212 		if (tsleep(&sc->sc_queuecnt, PRIBIO, "lddtch", 30 * hz))
213 			printf("%s: not drained\n", sc->sc_dv.dv_xname);
214 
215 	/* Locate the major numbers. */
216 	bmaj = bdevsw_lookup_major(&ld_bdevsw);
217 	cmaj = cdevsw_lookup_major(&ld_cdevsw);
218 
219 	/* Kill off any queued buffers. */
220 	s = splbio();
221 	while ((bp = BUFQ_GET(&sc->sc_bufq)) != NULL) {
222 		bp->b_error = EIO;
223 		bp->b_flags |= B_ERROR;
224 		bp->b_resid = bp->b_bcount;
225 		biodone(bp);
226 	}
227 	bufq_free(&sc->sc_bufq);
228 	splx(s);
229 
230 	/* Nuke the vnodes for any open instances. */
231 	for (i = 0; i < MAXPARTITIONS; i++) {
232 		mn = DISKMINOR(sc->sc_dv.dv_unit, i);
233 		vdevgone(bmaj, mn, mn, VBLK);
234 		vdevgone(cmaj, mn, mn, VCHR);
235 	}
236 
237 	/* Delete all of our wedges. */
238 	dkwedge_delall(&sc->sc_dk);
239 
240 	/* Detach from the disk list. */
241 	disk_detach(&sc->sc_dk);
242 
243 #if NRND > 0
244 	/* Unhook the entropy source. */
245 	rnd_detach_source(&sc->sc_rnd_source);
246 #endif
247 
248 	/*
249 	 * XXX We can't really flush the cache here, beceause the
250 	 * XXX device may already be non-existent from the controller's
251 	 * XXX perspective.
252 	 */
253 #if 0
254 	/* Flush the device's cache. */
255 	if (sc->sc_flush != NULL)
256 		if ((*sc->sc_flush)(sc) != 0)
257 			printf("%s: unable to flush cache\n",
258 			    sc->sc_dv.dv_xname);
259 #endif
260 }
261 
262 /* ARGSUSED */
263 static void
264 ldshutdown(void *cookie)
265 {
266 	struct ld_softc *sc;
267 	int i;
268 
269 	for (i = 0; i < ld_cd.cd_ndevs; i++) {
270 		if ((sc = device_lookup(&ld_cd, i)) == NULL)
271 			continue;
272 		if (sc->sc_flush != NULL && (*sc->sc_flush)(sc) != 0)
273 			printf("%s: unable to flush cache\n",
274 			    sc->sc_dv.dv_xname);
275 	}
276 }
277 
278 /* ARGSUSED */
279 static int
280 ldopen(dev_t dev, int flags, int fmt, struct proc *p)
281 {
282 	struct ld_softc *sc;
283 	int error, unit, part;
284 
285 	unit = DISKUNIT(dev);
286 	if ((sc = device_lookup(&ld_cd, unit)) == NULL)
287 		return (ENXIO);
288 	if ((sc->sc_flags & LDF_ENABLED) == 0)
289 		return (ENODEV);
290 	part = DISKPART(dev);
291 
292 	if ((error = lockmgr(&sc->sc_dk.dk_openlock, LK_EXCLUSIVE, NULL)) != 0)
293 		return (error);
294 
295 	if (sc->sc_dk.dk_openmask == 0) {
296 		/* Load the partition info if not already loaded. */
297 		if ((sc->sc_flags & LDF_VLABEL) == 0)
298 			ldgetdisklabel(sc);
299 	}
300 
301 	/* Check that the partition exists. */
302 	if (part != RAW_PART && (part >= sc->sc_dk.dk_label->d_npartitions ||
303 	    sc->sc_dk.dk_label->d_partitions[part].p_fstype == FS_UNUSED)) {
304 		error = ENXIO;
305 		goto bad1;
306 	}
307 
308 	/* Ensure only one open at a time. */
309 	switch (fmt) {
310 	case S_IFCHR:
311 		sc->sc_dk.dk_copenmask |= (1 << part);
312 		break;
313 	case S_IFBLK:
314 		sc->sc_dk.dk_bopenmask |= (1 << part);
315 		break;
316 	}
317 	sc->sc_dk.dk_openmask =
318 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
319 
320 	(void) lockmgr(&sc->sc_dk.dk_openlock, LK_RELEASE, NULL);
321 	return (0);
322 
323  bad1:
324 	(void) lockmgr(&sc->sc_dk.dk_openlock, LK_RELEASE, NULL);
325 	return (error);
326 }
327 
328 /* ARGSUSED */
329 static int
330 ldclose(dev_t dev, int flags, int fmt, struct proc *p)
331 {
332 	struct ld_softc *sc;
333 	int error, part, unit;
334 
335 	unit = DISKUNIT(dev);
336 	part = DISKPART(dev);
337 	sc = device_lookup(&ld_cd, unit);
338 
339 	if ((error = lockmgr(&sc->sc_dk.dk_openlock, LK_EXCLUSIVE, NULL)) != 0)
340 		return (error);
341 
342 	switch (fmt) {
343 	case S_IFCHR:
344 		sc->sc_dk.dk_copenmask &= ~(1 << part);
345 		break;
346 	case S_IFBLK:
347 		sc->sc_dk.dk_bopenmask &= ~(1 << part);
348 		break;
349 	}
350 	sc->sc_dk.dk_openmask =
351 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
352 
353 	if (sc->sc_dk.dk_openmask == 0) {
354 		if (sc->sc_flush != NULL && (*sc->sc_flush)(sc) != 0)
355 			printf("%s: unable to flush cache\n",
356 			    sc->sc_dv.dv_xname);
357 		if ((sc->sc_flags & LDF_KLABEL) == 0)
358 			sc->sc_flags &= ~LDF_VLABEL;
359 	}
360 
361 	(void) lockmgr(&sc->sc_dk.dk_openlock, LK_RELEASE, NULL);
362 	return (0);
363 }
364 
365 /* ARGSUSED */
366 static int
367 ldread(dev_t dev, struct uio *uio, int ioflag)
368 {
369 
370 	return (physio(ldstrategy, NULL, dev, B_READ, ldminphys, uio));
371 }
372 
373 /* ARGSUSED */
374 static int
375 ldwrite(dev_t dev, struct uio *uio, int ioflag)
376 {
377 
378 	return (physio(ldstrategy, NULL, dev, B_WRITE, ldminphys, uio));
379 }
380 
381 /* ARGSUSED */
382 static int
383 ldioctl(dev_t dev, u_long cmd, caddr_t addr, int32_t flag, struct proc *p)
384 {
385 	struct ld_softc *sc;
386 	int part, unit, error;
387 #ifdef __HAVE_OLD_DISKLABEL
388 	struct disklabel newlabel;
389 #endif
390 	struct disklabel *lp;
391 
392 	unit = DISKUNIT(dev);
393 	part = DISKPART(dev);
394 	sc = device_lookup(&ld_cd, unit);
395 	error = 0;
396 
397 	switch (cmd) {
398 	case DIOCGDINFO:
399 		memcpy(addr, sc->sc_dk.dk_label, sizeof(struct disklabel));
400 		return (0);
401 
402 #ifdef __HAVE_OLD_DISKLABEL
403 	case ODIOCGDINFO:
404 		newlabel = *(sc->sc_dk.dk_label);
405 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
406 			return ENOTTY;
407 		memcpy(addr, &newlabel, sizeof(struct olddisklabel));
408 		return (0);
409 #endif
410 
411 	case DIOCGPART:
412 		((struct partinfo *)addr)->disklab = sc->sc_dk.dk_label;
413 		((struct partinfo *)addr)->part =
414 		    &sc->sc_dk.dk_label->d_partitions[part];
415 		break;
416 
417 	case DIOCWDINFO:
418 	case DIOCSDINFO:
419 #ifdef __HAVE_OLD_DISKLABEL
420 	case ODIOCWDINFO:
421 	case ODIOCSDINFO:
422 
423 		if (cmd == ODIOCSDINFO || cmd == ODIOCWDINFO) {
424 			memset(&newlabel, 0, sizeof newlabel);
425 			memcpy(&newlabel, addr, sizeof (struct olddisklabel));
426 			lp = &newlabel;
427 		} else
428 #endif
429 		lp = (struct disklabel *)addr;
430 
431 		if ((flag & FWRITE) == 0)
432 			return (EBADF);
433 
434 		if ((error = lockmgr(&sc->sc_dk.dk_openlock, LK_EXCLUSIVE,
435 				     NULL)) != 0)
436 			return (error);
437 		sc->sc_flags |= LDF_LABELLING;
438 
439 		error = setdisklabel(sc->sc_dk.dk_label,
440 		    lp, /*sc->sc_dk.dk_openmask : */0,
441 		    sc->sc_dk.dk_cpulabel);
442 		if (error == 0 && (cmd == DIOCWDINFO
443 #ifdef __HAVE_OLD_DISKLABEL
444 		    || cmd == ODIOCWDINFO
445 #endif
446 		    ))
447 			error = writedisklabel(
448 			    MAKEDISKDEV(major(dev), DISKUNIT(dev), RAW_PART),
449 			    ldstrategy, sc->sc_dk.dk_label,
450 			    sc->sc_dk.dk_cpulabel);
451 
452 		sc->sc_flags &= ~LDF_LABELLING;
453 		(void) lockmgr(&sc->sc_dk.dk_openlock, LK_RELEASE, NULL);
454 		break;
455 
456 	case DIOCKLABEL:
457 		if ((flag & FWRITE) == 0)
458 			return (EBADF);
459 		if (*(int *)addr)
460 			sc->sc_flags |= LDF_KLABEL;
461 		else
462 			sc->sc_flags &= ~LDF_KLABEL;
463 		break;
464 
465 	case DIOCWLABEL:
466 		if ((flag & FWRITE) == 0)
467 			return (EBADF);
468 		if (*(int *)addr)
469 			sc->sc_flags |= LDF_WLABEL;
470 		else
471 			sc->sc_flags &= ~LDF_WLABEL;
472 		break;
473 
474 	case DIOCGDEFLABEL:
475 		ldgetdefaultlabel(sc, (struct disklabel *)addr);
476 		break;
477 
478 #ifdef __HAVE_OLD_DISKLABEL
479 	case ODIOCGDEFLABEL:
480 		ldgetdefaultlabel(sc, &newlabel);
481 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
482 			return ENOTTY;
483 		memcpy(addr, &newlabel, sizeof (struct olddisklabel));
484 		break;
485 #endif
486 
487 	case DIOCCACHESYNC:
488 		/*
489 		 * XXX Do we really need to care about having a writable
490 		 * file descriptor here?
491 		 */
492 		if ((flag & FWRITE) == 0)
493 			error = EBADF;
494 		else if (sc->sc_flush)
495 			error = (*sc->sc_flush)(sc);
496 		else
497 			error = 0;	/* XXX Error out instead? */
498 		break;
499 
500 	case DIOCAWEDGE:
501 	    {
502 	    	struct dkwedge_info *dkw = (void *) addr;
503 
504 		if ((flag & FWRITE) == 0)
505 			return (EBADF);
506 
507 		/* If the ioctl happens here, the parent is us. */
508 		strcpy(dkw->dkw_parent, sc->sc_dv.dv_xname);
509 		return (dkwedge_add(dkw));
510 	    }
511 
512 	case DIOCDWEDGE:
513 	    {
514 	    	struct dkwedge_info *dkw = (void *) addr;
515 
516 		if ((flag & FWRITE) == 0)
517 			return (EBADF);
518 
519 		/* If the ioctl happens here, the parent is us. */
520 		strcpy(dkw->dkw_parent, sc->sc_dv.dv_xname);
521 		return (dkwedge_del(dkw));
522 	    }
523 
524 	case DIOCLWEDGES:
525 	    {
526 	    	struct dkwedge_list *dkwl = (void *) addr;
527 
528 		return (dkwedge_list(&sc->sc_dk, dkwl, p));
529 	    }
530 
531 	default:
532 		error = ENOTTY;
533 		break;
534 	}
535 
536 	return (error);
537 }
538 
539 static void
540 ldstrategy(struct buf *bp)
541 {
542 	struct ld_softc *sc;
543 	struct disklabel *lp;
544 	daddr_t blkno;
545 	int s, part;
546 
547 	sc = device_lookup(&ld_cd, DISKUNIT(bp->b_dev));
548 	part = DISKPART(bp->b_dev);
549 
550 	if ((sc->sc_flags & LDF_DETACH) != 0) {
551 		bp->b_error = EIO;
552 		goto bad;
553 	}
554 
555 	lp = sc->sc_dk.dk_label;
556 
557 	/*
558 	 * The transfer must be a whole number of blocks and the offset must
559 	 * not be negative.
560 	 */
561 	if ((bp->b_bcount % lp->d_secsize) != 0 || bp->b_blkno < 0) {
562 		bp->b_error = EINVAL;
563 		goto bad;
564 	}
565 
566 	/* If it's a null transfer, return immediately. */
567 	if (bp->b_bcount == 0)
568 		goto done;
569 
570 	/*
571 	 * Do bounds checking and adjust the transfer.  If error, process.
572 	 * If past the end of partition, just return.
573 	 */
574 	if (part != RAW_PART &&
575 	    bounds_check_with_label(&sc->sc_dk, bp,
576 	    (sc->sc_flags & (LDF_WLABEL | LDF_LABELLING)) != 0) <= 0) {
577 		goto done;
578 	}
579 
580 	/*
581 	 * Convert the block number to absolute and put it in terms
582 	 * of the device's logical block size.
583 	 */
584 	if (lp->d_secsize == DEV_BSIZE)
585 		blkno = bp->b_blkno;
586 	else if (lp->d_secsize > DEV_BSIZE)
587 		blkno = bp->b_blkno / (lp->d_secsize / DEV_BSIZE);
588 	else
589 		blkno = bp->b_blkno * (DEV_BSIZE / lp->d_secsize);
590 
591 	if (part != RAW_PART)
592 		blkno += lp->d_partitions[part].p_offset;
593 
594 	bp->b_rawblkno = blkno;
595 
596 	s = splbio();
597 	BUFQ_PUT(&sc->sc_bufq, bp);
598 	ldstart(sc);
599 	splx(s);
600 	return;
601 
602  bad:
603 	bp->b_flags |= B_ERROR;
604  done:
605 	bp->b_resid = bp->b_bcount;
606 	biodone(bp);
607 }
608 
609 static void
610 ldstart(struct ld_softc *sc)
611 {
612 	struct buf *bp;
613 	int error;
614 
615 	while (sc->sc_queuecnt < sc->sc_maxqueuecnt) {
616 		/* See if there is work to do. */
617 		if ((bp = BUFQ_PEEK(&sc->sc_bufq)) == NULL)
618 			break;
619 
620 		disk_busy(&sc->sc_dk);
621 		sc->sc_queuecnt++;
622 
623 		if (__predict_true((error = (*sc->sc_start)(sc, bp)) == 0)) {
624 			/*
625 			 * The back-end is running the job; remove it from
626 			 * the queue.
627 			 */
628 			(void) BUFQ_GET(&sc->sc_bufq);
629 		} else  {
630 			disk_unbusy(&sc->sc_dk, 0, (bp->b_flags & B_READ));
631 			sc->sc_queuecnt--;
632 			if (error == EAGAIN) {
633 				/*
634 				 * Temporary resource shortage in the
635 				 * back-end; just defer the job until
636 				 * later.
637 				 *
638 				 * XXX We might consider a watchdog timer
639 				 * XXX to make sure we are kicked into action.
640 				 */
641 				break;
642 			} else {
643 				(void) BUFQ_GET(&sc->sc_bufq);
644 				bp->b_error = error;
645 				bp->b_flags |= B_ERROR;
646 				bp->b_resid = bp->b_bcount;
647 				biodone(bp);
648 			}
649 		}
650 	}
651 }
652 
653 void
654 lddone(struct ld_softc *sc, struct buf *bp)
655 {
656 
657 	if ((bp->b_flags & B_ERROR) != 0) {
658 		diskerr(bp, "ld", "error", LOG_PRINTF, 0, sc->sc_dk.dk_label);
659 		printf("\n");
660 	}
661 
662 	disk_unbusy(&sc->sc_dk, bp->b_bcount - bp->b_resid,
663 	    (bp->b_flags & B_READ));
664 #if NRND > 0
665 	rnd_add_uint32(&sc->sc_rnd_source, bp->b_rawblkno);
666 #endif
667 	biodone(bp);
668 
669 	if (--sc->sc_queuecnt <= sc->sc_maxqueuecnt) {
670 		if ((sc->sc_flags & LDF_DRAIN) != 0) {
671 			sc->sc_flags &= ~LDF_DRAIN;
672 			wakeup(&sc->sc_queuecnt);
673 		}
674 		ldstart(sc);
675 	}
676 }
677 
678 static int
679 ldsize(dev_t dev)
680 {
681 	struct ld_softc *sc;
682 	int part, unit, omask, size;
683 
684 	unit = DISKUNIT(dev);
685 	if ((sc = device_lookup(&ld_cd, unit)) == NULL)
686 		return (ENODEV);
687 	if ((sc->sc_flags & LDF_ENABLED) == 0)
688 		return (ENODEV);
689 	part = DISKPART(dev);
690 
691 	omask = sc->sc_dk.dk_openmask & (1 << part);
692 
693 	if (omask == 0 && ldopen(dev, 0, S_IFBLK, NULL) != 0)
694 		return (-1);
695 	else if (sc->sc_dk.dk_label->d_partitions[part].p_fstype != FS_SWAP)
696 		size = -1;
697 	else
698 		size = sc->sc_dk.dk_label->d_partitions[part].p_size *
699 		    (sc->sc_dk.dk_label->d_secsize / DEV_BSIZE);
700 	if (omask == 0 && ldclose(dev, 0, S_IFBLK, NULL) != 0)
701 		return (-1);
702 
703 	return (size);
704 }
705 
706 /*
707  * Load the label information from the specified device.
708  */
709 static void
710 ldgetdisklabel(struct ld_softc *sc)
711 {
712 	const char *errstring;
713 
714 	ldgetdefaultlabel(sc, sc->sc_dk.dk_label);
715 
716 	/* Call the generic disklabel extraction routine. */
717 	errstring = readdisklabel(MAKEDISKDEV(0, sc->sc_dv.dv_unit, RAW_PART),
718 	    ldstrategy, sc->sc_dk.dk_label, sc->sc_dk.dk_cpulabel);
719 	if (errstring != NULL)
720 		printf("%s: %s\n", sc->sc_dv.dv_xname, errstring);
721 
722 	/* In-core label now valid. */
723 	sc->sc_flags |= LDF_VLABEL;
724 }
725 
726 /*
727  * Construct a ficticious label.
728  */
729 static void
730 ldgetdefaultlabel(struct ld_softc *sc, struct disklabel *lp)
731 {
732 
733 	memset(lp, 0, sizeof(struct disklabel));
734 
735 	lp->d_secsize = sc->sc_secsize;
736 	lp->d_ntracks = sc->sc_nheads;
737 	lp->d_nsectors = sc->sc_nsectors;
738 	lp->d_ncylinders = sc->sc_ncylinders;
739 	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;
740 	lp->d_type = DTYPE_LD;
741 	strlcpy(lp->d_typename, "unknown", sizeof(lp->d_typename));
742 	strlcpy(lp->d_packname, "fictitious", sizeof(lp->d_packname));
743 	lp->d_secperunit = sc->sc_secperunit;
744 	lp->d_rpm = 7200;
745 	lp->d_interleave = 1;
746 	lp->d_flags = 0;
747 
748 	lp->d_partitions[RAW_PART].p_offset = 0;
749 	lp->d_partitions[RAW_PART].p_size =
750 	    lp->d_secperunit * (lp->d_secsize / DEV_BSIZE);
751 	lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
752 	lp->d_npartitions = RAW_PART + 1;
753 
754 	lp->d_magic = DISKMAGIC;
755 	lp->d_magic2 = DISKMAGIC;
756 	lp->d_checksum = dkcksum(lp);
757 }
758 
759 /*
760  * Take a dump.
761  */
762 static int
763 lddump(dev_t dev, daddr_t blkno, caddr_t va, size_t size)
764 {
765 	struct ld_softc *sc;
766 	struct disklabel *lp;
767 	int unit, part, nsects, sectoff, towrt, nblk, maxblkcnt, rv;
768 	static int dumping;
769 
770 	unit = DISKUNIT(dev);
771 	if ((sc = device_lookup(&ld_cd, unit)) == NULL)
772 		return (ENXIO);
773 	if ((sc->sc_flags & LDF_ENABLED) == 0)
774 		return (ENODEV);
775 	if (sc->sc_dump == NULL)
776 		return (ENXIO);
777 
778 	/* Check if recursive dump; if so, punt. */
779 	if (dumping)
780 		return (EFAULT);
781 	dumping = 1;
782 
783 	/* Convert to disk sectors.  Request must be a multiple of size. */
784 	part = DISKPART(dev);
785 	lp = sc->sc_dk.dk_label;
786 	if ((size % lp->d_secsize) != 0)
787 		return (EFAULT);
788 	towrt = size / lp->d_secsize;
789 	blkno = dbtob(blkno) / lp->d_secsize;	/* blkno in DEV_BSIZE units */
790 
791 	nsects = lp->d_partitions[part].p_size;
792 	sectoff = lp->d_partitions[part].p_offset;
793 
794 	/* Check transfer bounds against partition size. */
795 	if ((blkno < 0) || ((blkno + towrt) > nsects))
796 		return (EINVAL);
797 
798 	/* Offset block number to start of partition. */
799 	blkno += sectoff;
800 
801 	/* Start dumping and return when done. */
802 	maxblkcnt = sc->sc_maxxfer / sc->sc_secsize - 1;
803 	while (towrt > 0) {
804 		nblk = min(maxblkcnt, towrt);
805 
806 		if ((rv = (*sc->sc_dump)(sc, va, blkno, nblk)) != 0)
807 			return (rv);
808 
809 		towrt -= nblk;
810 		blkno += nblk;
811 		va += nblk * sc->sc_secsize;
812 	}
813 
814 	dumping = 0;
815 	return (0);
816 }
817 
818 /*
819  * Adjust the size of a transfer.
820  */
821 static void
822 ldminphys(struct buf *bp)
823 {
824 	struct ld_softc *sc;
825 
826 	sc = device_lookup(&ld_cd, DISKUNIT(bp->b_dev));
827 
828 	if (bp->b_bcount > sc->sc_maxxfer)
829 		bp->b_bcount = sc->sc_maxxfer;
830 	minphys(bp);
831 }
832