xref: /netbsd-src/sys/dev/ld.c (revision 5e4c038a45edbc7d63b7c2daa76e29f88b64a4e3)
1 /*	$NetBSD: ld.c,v 1.13 2002/05/08 15:49:07 drochner 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 1.13 2002/05/08 15:49:07 drochner 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 int	ldstart(struct ld_softc *, struct buf *);
77 static void	ldunlock(struct ld_softc *);
78 
79 extern struct	cfdriver ld_cd;
80 
81 static struct	dkdriver lddkdriver = { ldstrategy };
82 static void	*ld_sdh;
83 
84 void
85 ldattach(struct ld_softc *sc)
86 {
87 	char buf[9];
88 
89 	if ((sc->sc_flags & LDF_ENABLED) == 0) {
90 		printf("%s: disabled\n", sc->sc_dv.dv_xname);
91 		return;
92 	}
93 
94 	/* Initialise and attach the disk structure. */
95 	sc->sc_dk.dk_driver = &lddkdriver;
96 	sc->sc_dk.dk_name = sc->sc_dv.dv_xname;
97 	disk_attach(&sc->sc_dk);
98 
99 	if (sc->sc_maxxfer > MAXPHYS)
100 		sc->sc_maxxfer = MAXPHYS;
101 
102 	/* Build synthetic geometry. */
103 	if (sc->sc_secperunit <= 528 * 2048)		/* 528MB */
104 		sc->sc_nheads = 16;
105 	else if (sc->sc_secperunit <= 1024 * 2048)	/* 1GB */
106 		sc->sc_nheads = 32;
107 	else if (sc->sc_secperunit <= 21504 * 2048)	/* 21GB */
108 		sc->sc_nheads = 64;
109 	else if (sc->sc_secperunit <= 43008 * 2048)	/* 42GB */
110 		sc->sc_nheads = 128;
111 	else
112 		sc->sc_nheads = 255;
113 
114 	sc->sc_nsectors = 63;
115 	sc->sc_ncylinders = sc->sc_secperunit /
116 	    (sc->sc_nheads * sc->sc_nsectors);
117 
118 	format_bytes(buf, sizeof(buf), (u_int64_t)sc->sc_secperunit *
119 	    sc->sc_secsize);
120 	printf("%s: %s, %d cyl, %d head, %d sec, %d bytes/sect x %d sectors\n",
121 	    sc->sc_dv.dv_xname, buf, sc->sc_ncylinders, sc->sc_nheads,
122 	    sc->sc_nsectors, sc->sc_secsize, sc->sc_secperunit);
123 
124 #if NRND > 0
125 	/* Attach the device into the rnd source list. */
126 	rnd_attach_source(&sc->sc_rnd_source, sc->sc_dv.dv_xname,
127 	    RND_TYPE_DISK, 0);
128 #endif
129 
130 	/* Set the `shutdownhook'. */
131 	if (ld_sdh == NULL)
132 		ld_sdh = shutdownhook_establish(ldshutdown, NULL);
133 	BUFQ_INIT(&sc->sc_bufq);
134 }
135 
136 int
137 ldadjqparam(struct ld_softc *sc, int max)
138 {
139 	int s, rv;
140 
141 	s = splbio();
142 	sc->sc_maxqueuecnt = max;
143 	if (sc->sc_queuecnt > max) {
144 		sc->sc_flags |= LDF_DRAIN;
145 		rv = tsleep(&sc->sc_queuecnt, PRIBIO, "lddrn", 30 * hz);
146 		sc->sc_flags &= ~LDF_DRAIN;
147 	} else
148 		rv = 0;
149 	splx(s);
150 
151 	return (rv);
152 }
153 
154 int
155 ldbegindetach(struct ld_softc *sc, int flags)
156 {
157 	int s, rv;
158 
159 	if ((sc->sc_flags & LDF_ENABLED) == 0)
160 		return (0);
161 
162 	if ((flags & DETACH_FORCE) == 0 && sc->sc_dk.dk_openmask != 0)
163 		return (EBUSY);
164 
165 	s = splbio();
166 	sc->sc_flags |= LDF_DETACH;
167 	rv = ldadjqparam(sc, 0);
168 	splx(s);
169 
170 	return (rv);
171 }
172 
173 void
174 ldenddetach(struct ld_softc *sc)
175 {
176 	struct buf *bp;
177 	int s, bmaj, cmaj, i, mn;
178 
179 	if ((sc->sc_flags & LDF_ENABLED) == 0)
180 		return;
181 
182 	/* Wait for commands queued with the hardware to complete. */
183 	if (sc->sc_queuecnt != 0)
184 		if (tsleep(&sc->sc_queuecnt, PRIBIO, "lddtch", 30 * hz))
185 			printf("%s: not drained\n", sc->sc_dv.dv_xname);
186 
187 	/* Locate the major numbers. */
188 	for (bmaj = 0; bmaj <= nblkdev; bmaj++)
189 		if (bdevsw[bmaj].d_open == ldopen)
190 			break;
191 	for (cmaj = 0; cmaj <= nchrdev; cmaj++)
192 		if (cdevsw[cmaj].d_open == ldopen)
193 			break;
194 
195 	/* Kill off any queued buffers. */
196 	s = splbio();
197 	while ((bp = BUFQ_FIRST(&sc->sc_bufq)) != NULL) {
198 		BUFQ_REMOVE(&sc->sc_bufq, bp);
199 		bp->b_error = EIO;
200 		bp->b_flags |= B_ERROR;
201 		bp->b_resid = bp->b_bcount;
202 		biodone(bp);
203 	}
204 	splx(s);
205 
206 	/* Nuke the vnodes for any open instances. */
207 	for (i = 0; i < MAXPARTITIONS; i++) {
208 		mn = DISKMINOR(sc->sc_dv.dv_unit, i);
209 		vdevgone(bmaj, mn, mn, VBLK);
210 		vdevgone(cmaj, mn, mn, VCHR);
211 	}
212 
213 	/* Detach from the disk list. */
214 	disk_detach(&sc->sc_dk);
215 
216 #if NRND > 0
217 	/* Unhook the entropy source. */
218 	rnd_detach_source(&sc->sc_rnd_source);
219 #endif
220 
221 	/* Flush the device's cache. */
222 	if (sc->sc_flush != NULL)
223 		if ((*sc->sc_flush)(sc) != 0)
224 			printf("%s: unable to flush cache\n",
225 			    sc->sc_dv.dv_xname);
226 }
227 
228 /* ARGSUSED */
229 static void
230 ldshutdown(void *cookie)
231 {
232 	struct ld_softc *sc;
233 	int i;
234 
235 	for (i = 0; i < ld_cd.cd_ndevs; i++) {
236 		if ((sc = device_lookup(&ld_cd, i)) == NULL)
237 			continue;
238 		if (sc->sc_flush != NULL && (*sc->sc_flush)(sc) != 0)
239 			printf("%s: unable to flush cache\n",
240 			    sc->sc_dv.dv_xname);
241 	}
242 }
243 
244 /* ARGSUSED */
245 int
246 ldopen(dev_t dev, int flags, int fmt, struct proc *p)
247 {
248 	struct ld_softc *sc;
249 	int unit, part;
250 
251 	unit = DISKUNIT(dev);
252 	if ((sc = device_lookup(&ld_cd, unit))== NULL)
253 		return (ENXIO);
254 	if ((sc->sc_flags & LDF_ENABLED) == 0)
255 		return (ENODEV);
256 	part = DISKPART(dev);
257 	ldlock(sc);
258 
259 	if (sc->sc_dk.dk_openmask == 0)
260 		ldgetdisklabel(sc);
261 
262 	/* Check that the partition exists. */
263 	if (part != RAW_PART && (part >= sc->sc_dk.dk_label->d_npartitions ||
264 	    sc->sc_dk.dk_label->d_partitions[part].p_fstype == FS_UNUSED)) {
265 	     	ldunlock(sc);
266 		return (ENXIO);
267 	}
268 
269 	/* Ensure only one open at a time. */
270 	switch (fmt) {
271 	case S_IFCHR:
272 		sc->sc_dk.dk_copenmask |= (1 << part);
273 		break;
274 	case S_IFBLK:
275 		sc->sc_dk.dk_bopenmask |= (1 << part);
276 		break;
277 	}
278 	sc->sc_dk.dk_openmask =
279 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
280 
281 	ldunlock(sc);
282 	return (0);
283 }
284 
285 /* ARGSUSED */
286 int
287 ldclose(dev_t dev, int flags, int fmt, struct proc *p)
288 {
289 	struct ld_softc *sc;
290 	int part, unit;
291 
292 	unit = DISKUNIT(dev);
293 	part = DISKPART(dev);
294 	sc = device_lookup(&ld_cd, unit);
295 	ldlock(sc);
296 
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 	if (sc->sc_dk.dk_openmask == 0 && sc->sc_flush != NULL)
309 		if ((*sc->sc_flush)(sc) != 0)
310 			printf("%s: unable to flush cache\n",
311 			    sc->sc_dv.dv_xname);
312 
313 	ldunlock(sc);
314 	return (0);
315 }
316 
317 /* ARGSUSED */
318 int
319 ldread(dev_t dev, struct uio *uio, int ioflag)
320 {
321 
322 	return (physio(ldstrategy, NULL, dev, B_READ, ldminphys, uio));
323 }
324 
325 /* ARGSUSED */
326 int
327 ldwrite(dev_t dev, struct uio *uio, int ioflag)
328 {
329 
330 	return (physio(ldstrategy, NULL, dev, B_WRITE, ldminphys, uio));
331 }
332 
333 /* ARGSUSED */
334 int
335 ldioctl(dev_t dev, u_long cmd, caddr_t addr, int32_t flag, struct proc *p)
336 {
337 	struct ld_softc *sc;
338 	int part, unit, error;
339 #ifdef __HAVE_OLD_DISKLABEL
340 	struct disklabel newlabel;
341 #endif
342 	struct disklabel *lp;
343 
344 	unit = DISKUNIT(dev);
345 	part = DISKPART(dev);
346 	sc = device_lookup(&ld_cd, unit);
347 	error = 0;
348 
349 	switch (cmd) {
350 	case DIOCGDINFO:
351 		memcpy(addr, sc->sc_dk.dk_label, sizeof(struct disklabel));
352 		return (0);
353 
354 #ifdef __HAVE_OLD_DISKLABEL
355 	case ODIOCGDINFO:
356 		newlabel = *(sc->sc_dk.dk_label);
357 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
358 			return ENOTTY;
359 		memcpy(addr, &newlabel, sizeof(struct olddisklabel));
360 		return (0);
361 #endif
362 
363 	case DIOCGPART:
364 		((struct partinfo *)addr)->disklab = sc->sc_dk.dk_label;
365 		((struct partinfo *)addr)->part =
366 		    &sc->sc_dk.dk_label->d_partitions[part];
367 		break;
368 
369 	case DIOCWDINFO:
370 	case DIOCSDINFO:
371 #ifdef __HAVE_OLD_DISKLABEL
372 	case ODIOCWDINFO:
373 	case ODIOCSDINFO:
374 
375 		if (cmd == ODIOCSDINFO || cmd == ODIOCWDINFO) {
376 			memset(&newlabel, 0, sizeof newlabel);
377 			memcpy(&newlabel, addr, sizeof (struct olddisklabel));
378 			lp = &newlabel;
379 		} else
380 #endif
381 		lp = (struct disklabel *)addr;
382 
383 		if ((flag & FWRITE) == 0)
384 			return (EBADF);
385 
386 		if ((error = ldlock(sc)) != 0)
387 			return (error);
388 		sc->sc_flags |= LDF_LABELLING;
389 
390 		error = setdisklabel(sc->sc_dk.dk_label,
391 		    lp, /*sc->sc_dk.dk_openmask : */0,
392 		    sc->sc_dk.dk_cpulabel);
393 		if (error == 0 && (cmd == DIOCWDINFO
394 #ifdef __HAVE_OLD_DISKLABEL
395 		    || cmd == ODIOCWDINFO
396 #endif
397 		    ))
398 			error = writedisklabel(
399 			    MAKEDISKDEV(major(dev), DISKUNIT(dev), RAW_PART),
400 			    ldstrategy, sc->sc_dk.dk_label,
401 			    sc->sc_dk.dk_cpulabel);
402 
403 		sc->sc_flags &= ~LDF_LABELLING;
404 		ldunlock(sc);
405 		break;
406 
407 	case DIOCWLABEL:
408 		if ((flag & FWRITE) == 0)
409 			return (EBADF);
410 		if (*(int *)addr)
411 			sc->sc_flags |= LDF_WLABEL;
412 		else
413 			sc->sc_flags &= ~LDF_WLABEL;
414 		break;
415 
416 	case DIOCGDEFLABEL:
417 		ldgetdefaultlabel(sc, (struct disklabel *)addr);
418 		break;
419 
420 #ifdef __HAVE_OLD_DISKLABEL
421 	case ODIOCGDEFLABEL:
422 		ldgetdefaultlabel(sc, &newlabel);
423 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
424 			return ENOTTY;
425 		memcpy(addr, &newlabel, sizeof (struct olddisklabel));
426 		break;
427 #endif
428 
429 	default:
430 		error = ENOTTY;
431 		break;
432 	}
433 
434 	return (error);
435 }
436 
437 void
438 ldstrategy(struct buf *bp)
439 {
440 	struct ld_softc *sc;
441 	int s;
442 
443 	sc = device_lookup(&ld_cd, DISKUNIT(bp->b_dev));
444 
445 	s = splbio();
446 	if (sc->sc_queuecnt >= sc->sc_maxqueuecnt) {
447 		BUFQ_INSERT_TAIL(&sc->sc_bufq, bp);
448 		splx(s);
449 		return;
450 	}
451 	splx(s);
452 	ldstart(sc, bp);
453 }
454 
455 static int
456 ldstart(struct ld_softc *sc, struct buf *bp)
457 {
458 	struct disklabel *lp;
459 	int part, s, rv;
460 
461 	if ((sc->sc_flags & LDF_DETACH) != 0) {
462 		bp->b_error = EIO;
463 		bp->b_flags |= B_ERROR;
464 		bp->b_resid = bp->b_bcount;
465 		biodone(bp);
466 		return (-1);
467 	}
468 
469 	part = DISKPART(bp->b_dev);
470 	lp = sc->sc_dk.dk_label;
471 
472 	/*
473 	 * The transfer must be a whole number of blocks and the offset must
474 	 * not be negative.
475 	 */
476 	if ((bp->b_bcount % lp->d_secsize) != 0 || bp->b_blkno < 0) {
477 		bp->b_flags |= B_ERROR;
478 		biodone(bp);
479 		return (-1);
480 	}
481 
482 	/*
483 	 * If it's a null transfer, return.
484 	 */
485 	if (bp->b_bcount == 0) {
486 		bp->b_resid = bp->b_bcount;
487 		biodone(bp);
488 		return (-1);
489 	}
490 
491 	/*
492 	 * Do bounds checking and adjust the transfer.  If error, process.
493 	 * If past the end of partition, just return.
494 	 */
495 	if (part != RAW_PART &&
496 	    bounds_check_with_label(bp, lp,
497 	    (sc->sc_flags & (LDF_WLABEL | LDF_LABELLING)) != 0) <= 0) {
498 		bp->b_resid = bp->b_bcount;
499 		biodone(bp);
500 		return (-1);
501 	}
502 
503 	/*
504 	 * Convert the logical block number to a physical one and put it in
505 	 * terms of the device's logical block size.
506 	 */
507 	if (lp->d_secsize >= DEV_BSIZE)
508 		bp->b_rawblkno = bp->b_blkno / (lp->d_secsize / DEV_BSIZE);
509 	else
510 		bp->b_rawblkno = bp->b_blkno * (DEV_BSIZE / lp->d_secsize);
511 
512 	if (part != RAW_PART)
513 		bp->b_rawblkno += lp->d_partitions[part].p_offset;
514 
515 	s = splbio();
516 	disk_busy(&sc->sc_dk);
517 	sc->sc_queuecnt++;
518 	splx(s);
519 
520 	if ((rv = (*sc->sc_start)(sc, bp)) != 0) {
521 		bp->b_error = rv;
522 		bp->b_flags |= B_ERROR;
523 		bp->b_resid = bp->b_bcount;
524 		s = splbio();
525 		lddone(sc, bp);
526 		splx(s);
527 	}
528 
529 	return (0);
530 }
531 
532 void
533 lddone(struct ld_softc *sc, struct buf *bp)
534 {
535 
536 	if ((bp->b_flags & B_ERROR) != 0) {
537 		diskerr(bp, "ld", "error", LOG_PRINTF, 0, sc->sc_dk.dk_label);
538 		printf("\n");
539 	}
540 
541 	disk_unbusy(&sc->sc_dk, bp->b_bcount - bp->b_resid);
542 #if NRND > 0
543 	rnd_add_uint32(&sc->sc_rnd_source, bp->b_rawblkno);
544 #endif
545 	biodone(bp);
546 
547 	if (--sc->sc_queuecnt <= sc->sc_maxqueuecnt) {
548 		if ((sc->sc_flags & LDF_DRAIN) != 0)
549 			wakeup(&sc->sc_queuecnt);
550 		while ((bp = BUFQ_FIRST(&sc->sc_bufq)) != NULL) {
551 			BUFQ_REMOVE(&sc->sc_bufq, bp);
552 			if (!ldstart(sc, bp))
553 				break;
554 		}
555 	}
556 }
557 
558 int
559 ldsize(dev_t dev)
560 {
561 	struct ld_softc *sc;
562 	int part, unit, omask, size;
563 
564 	unit = DISKUNIT(dev);
565 	if ((sc = device_lookup(&ld_cd, unit)) == NULL)
566 		return (ENODEV);
567 	if ((sc->sc_flags & LDF_ENABLED) == 0)
568 		return (ENODEV);
569 	part = DISKPART(dev);
570 
571 	omask = sc->sc_dk.dk_openmask & (1 << part);
572 
573 	if (omask == 0 && ldopen(dev, 0, S_IFBLK, NULL) != 0)
574 		return (-1);
575 	else if (sc->sc_dk.dk_label->d_partitions[part].p_fstype != FS_SWAP)
576 		size = -1;
577 	else
578 		size = sc->sc_dk.dk_label->d_partitions[part].p_size *
579 		    (sc->sc_dk.dk_label->d_secsize / DEV_BSIZE);
580 	if (omask == 0 && ldclose(dev, 0, S_IFBLK, NULL) != 0)
581 		return (-1);
582 
583 	return (size);
584 }
585 
586 /*
587  * Load the label information from the specified device.
588  */
589 static void
590 ldgetdisklabel(struct ld_softc *sc)
591 {
592 	const char *errstring;
593 
594 	ldgetdefaultlabel(sc, sc->sc_dk.dk_label);
595 
596 	/* Call the generic disklabel extraction routine. */
597 	errstring = readdisklabel(MAKEDISKDEV(0, sc->sc_dv.dv_unit, RAW_PART),
598 	    ldstrategy, sc->sc_dk.dk_label, sc->sc_dk.dk_cpulabel);
599 	if (errstring != NULL)
600 		printf("%s: %s\n", sc->sc_dv.dv_xname, errstring);
601 }
602 
603 /*
604  * Construct a ficticious label.
605  */
606 static void
607 ldgetdefaultlabel(struct ld_softc *sc, struct disklabel *lp)
608 {
609 
610 	memset(lp, 0, sizeof(struct disklabel));
611 
612 	lp->d_secsize = sc->sc_secsize;
613 	lp->d_ntracks = sc->sc_nheads;
614 	lp->d_nsectors = sc->sc_nsectors;
615 	lp->d_ncylinders = sc->sc_ncylinders;
616 	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;
617 	lp->d_type = DTYPE_LD;
618 	strcpy(lp->d_typename, "unknown");
619 	strcpy(lp->d_packname, "fictitious");
620 	lp->d_secperunit = sc->sc_secperunit;
621 	lp->d_rpm = 7200;
622 	lp->d_interleave = 1;
623 	lp->d_flags = 0;
624 
625 	lp->d_partitions[RAW_PART].p_offset = 0;
626 	lp->d_partitions[RAW_PART].p_size =
627 	    lp->d_secperunit * (lp->d_secsize / DEV_BSIZE);
628 	lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
629 	lp->d_npartitions = RAW_PART + 1;
630 
631 	lp->d_magic = DISKMAGIC;
632 	lp->d_magic2 = DISKMAGIC;
633 	lp->d_checksum = dkcksum(lp);
634 }
635 
636 /*
637  * Wait interruptibly for an exclusive lock.
638  *
639  * XXX Several drivers do this; it should be abstracted and made MP-safe.
640  */
641 static int
642 ldlock(struct ld_softc *sc)
643 {
644 	int error;
645 
646 	while ((sc->sc_flags & LDF_LKHELD) != 0) {
647 		sc->sc_flags |= LDF_LKWANTED;
648 		if ((error = tsleep(sc, PRIBIO | PCATCH, "ldlck", 0)) != 0)
649 			return (error);
650 	}
651 	sc->sc_flags |= LDF_LKHELD;
652 	return (0);
653 }
654 
655 /*
656  * Unlock and wake up any waiters.
657  */
658 static void
659 ldunlock(struct ld_softc *sc)
660 {
661 
662 	sc->sc_flags &= ~LDF_LKHELD;
663 	if ((sc->sc_flags & LDF_LKWANTED) != 0) {
664 		sc->sc_flags &= ~LDF_LKWANTED;
665 		wakeup(sc);
666 	}
667 }
668 
669 /*
670  * Take a dump.
671  */
672 int
673 lddump(dev_t dev, daddr_t blkno, caddr_t va, size_t size)
674 {
675 	struct ld_softc *sc;
676 	struct disklabel *lp;
677 	int unit, part, nsects, sectoff, towrt, nblk, maxblkcnt, rv;
678 	static int dumping;
679 
680 	unit = DISKUNIT(dev);
681 	if ((sc = device_lookup(&ld_cd, unit)) == NULL)
682 		return (ENXIO);
683 	if ((sc->sc_flags & LDF_ENABLED) == 0)
684 		return (ENODEV);
685 	if (sc->sc_dump == NULL)
686 		return (ENXIO);
687 
688 	/* Check if recursive dump; if so, punt. */
689 	if (dumping)
690 		return (EFAULT);
691 	dumping = 1;
692 
693 	/* Convert to disk sectors.  Request must be a multiple of size. */
694 	part = DISKPART(dev);
695 	lp = sc->sc_dk.dk_label;
696 	if ((size % lp->d_secsize) != 0)
697 		return (EFAULT);
698 	towrt = size / lp->d_secsize;
699 	blkno = dbtob(blkno) / lp->d_secsize;	/* blkno in DEV_BSIZE units */
700 
701 	nsects = lp->d_partitions[part].p_size;
702 	sectoff = lp->d_partitions[part].p_offset;
703 
704 	/* Check transfer bounds against partition size. */
705 	if ((blkno < 0) || ((blkno + towrt) > nsects))
706 		return (EINVAL);
707 
708 	/* Offset block number to start of partition. */
709 	blkno += sectoff;
710 
711 	/* Start dumping and return when done. */
712 	maxblkcnt = sc->sc_maxxfer / sc->sc_secsize - 1;
713 	while (towrt > 0) {
714 		nblk = min(maxblkcnt, towrt);
715 
716 		if ((rv = (*sc->sc_dump)(sc, va, blkno, nblk)) != 0)
717 			return (rv);
718 
719 		towrt -= nblk;
720 		blkno += nblk;
721 		va += nblk * sc->sc_secsize;
722 	}
723 
724 	dumping = 0;
725 	return (0);
726 }
727 
728 /*
729  * Adjust the size of a transfer.
730  */
731 static void
732 ldminphys(struct buf *bp)
733 {
734 	struct ld_softc *sc;
735 
736 	sc = device_lookup(&ld_cd, DISKUNIT(bp->b_dev));
737 
738 	if (bp->b_bcount > sc->sc_maxxfer)
739 		bp->b_bcount = sc->sc_maxxfer;
740 	minphys(bp);
741 }
742