xref: /netbsd-src/sys/dev/ld.c (revision 1ca5c1b28139779176bd5c13ad7c5f25c0bcd5f8)
1 /*	$NetBSD: ld.c,v 1.12 2001/11/13 05:32:50 lukem 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 1.12 2001/11/13 05:32:50 lukem 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, 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 	mn = DISKUNIT(sc->sc_dv.dv_unit);
208 	vdevgone(bmaj, mn, mn + (MAXPARTITIONS - 1), VBLK);
209 	vdevgone(cmaj, mn, mn + (MAXPARTITIONS - 1), VCHR);
210 
211 	/* Detach from the disk list. */
212 	disk_detach(&sc->sc_dk);
213 
214 #if NRND > 0
215 	/* Unhook the entropy source. */
216 	rnd_detach_source(&sc->sc_rnd_source);
217 #endif
218 
219 	/* Flush the device's cache. */
220 	if (sc->sc_flush != NULL)
221 		if ((*sc->sc_flush)(sc) != 0)
222 			printf("%s: unable to flush cache\n",
223 			    sc->sc_dv.dv_xname);
224 }
225 
226 /* ARGSUSED */
227 static void
228 ldshutdown(void *cookie)
229 {
230 	struct ld_softc *sc;
231 	int i;
232 
233 	for (i = 0; i < ld_cd.cd_ndevs; i++) {
234 		if ((sc = device_lookup(&ld_cd, i)) == NULL)
235 			continue;
236 		if (sc->sc_flush != NULL && (*sc->sc_flush)(sc) != 0)
237 			printf("%s: unable to flush cache\n",
238 			    sc->sc_dv.dv_xname);
239 	}
240 }
241 
242 /* ARGSUSED */
243 int
244 ldopen(dev_t dev, int flags, int fmt, struct proc *p)
245 {
246 	struct ld_softc *sc;
247 	int unit, part;
248 
249 	unit = DISKUNIT(dev);
250 	if ((sc = device_lookup(&ld_cd, unit))== NULL)
251 		return (ENXIO);
252 	if ((sc->sc_flags & LDF_ENABLED) == 0)
253 		return (ENODEV);
254 	part = DISKPART(dev);
255 	ldlock(sc);
256 
257 	if (sc->sc_dk.dk_openmask == 0)
258 		ldgetdisklabel(sc);
259 
260 	/* Check that the partition exists. */
261 	if (part != RAW_PART && (part >= sc->sc_dk.dk_label->d_npartitions ||
262 	    sc->sc_dk.dk_label->d_partitions[part].p_fstype == FS_UNUSED)) {
263 	     	ldunlock(sc);
264 		return (ENXIO);
265 	}
266 
267 	/* Ensure only one open at a time. */
268 	switch (fmt) {
269 	case S_IFCHR:
270 		sc->sc_dk.dk_copenmask |= (1 << part);
271 		break;
272 	case S_IFBLK:
273 		sc->sc_dk.dk_bopenmask |= (1 << part);
274 		break;
275 	}
276 	sc->sc_dk.dk_openmask =
277 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
278 
279 	ldunlock(sc);
280 	return (0);
281 }
282 
283 /* ARGSUSED */
284 int
285 ldclose(dev_t dev, int flags, int fmt, struct proc *p)
286 {
287 	struct ld_softc *sc;
288 	int part, unit;
289 
290 	unit = DISKUNIT(dev);
291 	part = DISKPART(dev);
292 	sc = device_lookup(&ld_cd, unit);
293 	ldlock(sc);
294 
295 	switch (fmt) {
296 	case S_IFCHR:
297 		sc->sc_dk.dk_copenmask &= ~(1 << part);
298 		break;
299 	case S_IFBLK:
300 		sc->sc_dk.dk_bopenmask &= ~(1 << part);
301 		break;
302 	}
303 	sc->sc_dk.dk_openmask =
304 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
305 
306 	if (sc->sc_dk.dk_openmask == 0 && sc->sc_flush != NULL)
307 		if ((*sc->sc_flush)(sc) != 0)
308 			printf("%s: unable to flush cache\n",
309 			    sc->sc_dv.dv_xname);
310 
311 	ldunlock(sc);
312 	return (0);
313 }
314 
315 /* ARGSUSED */
316 int
317 ldread(dev_t dev, struct uio *uio, int ioflag)
318 {
319 
320 	return (physio(ldstrategy, NULL, dev, B_READ, ldminphys, uio));
321 }
322 
323 /* ARGSUSED */
324 int
325 ldwrite(dev_t dev, struct uio *uio, int ioflag)
326 {
327 
328 	return (physio(ldstrategy, NULL, dev, B_WRITE, ldminphys, uio));
329 }
330 
331 /* ARGSUSED */
332 int
333 ldioctl(dev_t dev, u_long cmd, caddr_t addr, int32_t flag, struct proc *p)
334 {
335 	struct ld_softc *sc;
336 	int part, unit, error;
337 #ifdef __HAVE_OLD_DISKLABEL
338 	struct disklabel newlabel;
339 #endif
340 	struct disklabel *lp;
341 
342 	unit = DISKUNIT(dev);
343 	part = DISKPART(dev);
344 	sc = device_lookup(&ld_cd, unit);
345 	error = 0;
346 
347 	switch (cmd) {
348 	case DIOCGDINFO:
349 		memcpy(addr, sc->sc_dk.dk_label, sizeof(struct disklabel));
350 		return (0);
351 
352 #ifdef __HAVE_OLD_DISKLABEL
353 	case ODIOCGDINFO:
354 		newlabel = *(sc->sc_dk.dk_label);
355 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
356 			return ENOTTY;
357 		memcpy(addr, &newlabel, sizeof(struct olddisklabel));
358 		return (0);
359 #endif
360 
361 	case DIOCGPART:
362 		((struct partinfo *)addr)->disklab = sc->sc_dk.dk_label;
363 		((struct partinfo *)addr)->part =
364 		    &sc->sc_dk.dk_label->d_partitions[part];
365 		break;
366 
367 	case DIOCWDINFO:
368 	case DIOCSDINFO:
369 #ifdef __HAVE_OLD_DISKLABEL
370 	case ODIOCWDINFO:
371 	case ODIOCSDINFO:
372 
373 		if (cmd == ODIOCSDINFO || cmd == ODIOCWDINFO) {
374 			memset(&newlabel, 0, sizeof newlabel);
375 			memcpy(&newlabel, addr, sizeof (struct olddisklabel));
376 			lp = &newlabel;
377 		} else
378 #endif
379 		lp = (struct disklabel *)addr;
380 
381 		if ((flag & FWRITE) == 0)
382 			return (EBADF);
383 
384 		if ((error = ldlock(sc)) != 0)
385 			return (error);
386 		sc->sc_flags |= LDF_LABELLING;
387 
388 		error = setdisklabel(sc->sc_dk.dk_label,
389 		    lp, /*sc->sc_dk.dk_openmask : */0,
390 		    sc->sc_dk.dk_cpulabel);
391 		if (error == 0 && (cmd == DIOCWDINFO
392 #ifdef __HAVE_OLD_DISKLABEL
393 		    || cmd == ODIOCWDINFO
394 #endif
395 		    ))
396 			error = writedisklabel(
397 			    MAKEDISKDEV(major(dev), DISKUNIT(dev), RAW_PART),
398 			    ldstrategy, sc->sc_dk.dk_label,
399 			    sc->sc_dk.dk_cpulabel);
400 
401 		sc->sc_flags &= ~LDF_LABELLING;
402 		ldunlock(sc);
403 		break;
404 
405 	case DIOCWLABEL:
406 		if ((flag & FWRITE) == 0)
407 			return (EBADF);
408 		if (*(int *)addr)
409 			sc->sc_flags |= LDF_WLABEL;
410 		else
411 			sc->sc_flags &= ~LDF_WLABEL;
412 		break;
413 
414 	case DIOCGDEFLABEL:
415 		ldgetdefaultlabel(sc, (struct disklabel *)addr);
416 		break;
417 
418 #ifdef __HAVE_OLD_DISKLABEL
419 	case ODIOCGDEFLABEL:
420 		ldgetdefaultlabel(sc, &newlabel);
421 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
422 			return ENOTTY;
423 		memcpy(addr, &newlabel, sizeof (struct olddisklabel));
424 		break;
425 #endif
426 
427 	default:
428 		error = ENOTTY;
429 		break;
430 	}
431 
432 	return (error);
433 }
434 
435 void
436 ldstrategy(struct buf *bp)
437 {
438 	struct ld_softc *sc;
439 	int s;
440 
441 	sc = device_lookup(&ld_cd, DISKUNIT(bp->b_dev));
442 
443 	s = splbio();
444 	if (sc->sc_queuecnt >= sc->sc_maxqueuecnt) {
445 		BUFQ_INSERT_TAIL(&sc->sc_bufq, bp);
446 		splx(s);
447 		return;
448 	}
449 	splx(s);
450 	ldstart(sc, bp);
451 }
452 
453 static int
454 ldstart(struct ld_softc *sc, struct buf *bp)
455 {
456 	struct disklabel *lp;
457 	int part, s, rv;
458 
459 	if ((sc->sc_flags & LDF_DETACH) != 0) {
460 		bp->b_error = EIO;
461 		bp->b_flags |= B_ERROR;
462 		bp->b_resid = bp->b_bcount;
463 		biodone(bp);
464 		return (-1);
465 	}
466 
467 	part = DISKPART(bp->b_dev);
468 	lp = sc->sc_dk.dk_label;
469 
470 	/*
471 	 * The transfer must be a whole number of blocks and the offset must
472 	 * not be negative.
473 	 */
474 	if ((bp->b_bcount % lp->d_secsize) != 0 || bp->b_blkno < 0) {
475 		bp->b_flags |= B_ERROR;
476 		biodone(bp);
477 		return (-1);
478 	}
479 
480 	/*
481 	 * If it's a null transfer, return.
482 	 */
483 	if (bp->b_bcount == 0) {
484 		bp->b_resid = bp->b_bcount;
485 		biodone(bp);
486 		return (-1);
487 	}
488 
489 	/*
490 	 * Do bounds checking and adjust the transfer.  If error, process.
491 	 * If past the end of partition, just return.
492 	 */
493 	if (part != RAW_PART &&
494 	    bounds_check_with_label(bp, lp,
495 	    (sc->sc_flags & (LDF_WLABEL | LDF_LABELLING)) != 0) <= 0) {
496 		bp->b_resid = bp->b_bcount;
497 		biodone(bp);
498 		return (-1);
499 	}
500 
501 	/*
502 	 * Convert the logical block number to a physical one and put it in
503 	 * terms of the device's logical block size.
504 	 */
505 	if (lp->d_secsize >= DEV_BSIZE)
506 		bp->b_rawblkno = bp->b_blkno / (lp->d_secsize / DEV_BSIZE);
507 	else
508 		bp->b_rawblkno = bp->b_blkno * (DEV_BSIZE / lp->d_secsize);
509 
510 	if (part != RAW_PART)
511 		bp->b_rawblkno += lp->d_partitions[part].p_offset;
512 
513 	s = splbio();
514 	disk_busy(&sc->sc_dk);
515 	sc->sc_queuecnt++;
516 	splx(s);
517 
518 	if ((rv = (*sc->sc_start)(sc, bp)) != 0) {
519 		bp->b_error = rv;
520 		bp->b_flags |= B_ERROR;
521 		bp->b_resid = bp->b_bcount;
522 		s = splbio();
523 		lddone(sc, bp);
524 		splx(s);
525 	}
526 
527 	return (0);
528 }
529 
530 void
531 lddone(struct ld_softc *sc, struct buf *bp)
532 {
533 
534 	if ((bp->b_flags & B_ERROR) != 0) {
535 		diskerr(bp, "ld", "error", LOG_PRINTF, 0, sc->sc_dk.dk_label);
536 		printf("\n");
537 	}
538 
539 	disk_unbusy(&sc->sc_dk, bp->b_bcount - bp->b_resid);
540 #if NRND > 0
541 	rnd_add_uint32(&sc->sc_rnd_source, bp->b_rawblkno);
542 #endif
543 	biodone(bp);
544 
545 	if (--sc->sc_queuecnt <= sc->sc_maxqueuecnt) {
546 		if ((sc->sc_flags & LDF_DRAIN) != 0)
547 			wakeup(&sc->sc_queuecnt);
548 		while ((bp = BUFQ_FIRST(&sc->sc_bufq)) != NULL) {
549 			BUFQ_REMOVE(&sc->sc_bufq, bp);
550 			if (!ldstart(sc, bp))
551 				break;
552 		}
553 	}
554 }
555 
556 int
557 ldsize(dev_t dev)
558 {
559 	struct ld_softc *sc;
560 	int part, unit, omask, size;
561 
562 	unit = DISKUNIT(dev);
563 	if ((sc = device_lookup(&ld_cd, unit)) == NULL)
564 		return (ENODEV);
565 	if ((sc->sc_flags & LDF_ENABLED) == 0)
566 		return (ENODEV);
567 	part = DISKPART(dev);
568 
569 	omask = sc->sc_dk.dk_openmask & (1 << part);
570 
571 	if (omask == 0 && ldopen(dev, 0, S_IFBLK, NULL) != 0)
572 		return (-1);
573 	else if (sc->sc_dk.dk_label->d_partitions[part].p_fstype != FS_SWAP)
574 		size = -1;
575 	else
576 		size = sc->sc_dk.dk_label->d_partitions[part].p_size *
577 		    (sc->sc_dk.dk_label->d_secsize / DEV_BSIZE);
578 	if (omask == 0 && ldclose(dev, 0, S_IFBLK, NULL) != 0)
579 		return (-1);
580 
581 	return (size);
582 }
583 
584 /*
585  * Load the label information from the specified device.
586  */
587 static void
588 ldgetdisklabel(struct ld_softc *sc)
589 {
590 	const char *errstring;
591 
592 	ldgetdefaultlabel(sc, sc->sc_dk.dk_label);
593 
594 	/* Call the generic disklabel extraction routine. */
595 	errstring = readdisklabel(MAKEDISKDEV(0, sc->sc_dv.dv_unit, RAW_PART),
596 	    ldstrategy, sc->sc_dk.dk_label, sc->sc_dk.dk_cpulabel);
597 	if (errstring != NULL)
598 		printf("%s: %s\n", sc->sc_dv.dv_xname, errstring);
599 }
600 
601 /*
602  * Construct a ficticious label.
603  */
604 static void
605 ldgetdefaultlabel(struct ld_softc *sc, struct disklabel *lp)
606 {
607 
608 	memset(lp, 0, sizeof(struct disklabel));
609 
610 	lp->d_secsize = sc->sc_secsize;
611 	lp->d_ntracks = sc->sc_nheads;
612 	lp->d_nsectors = sc->sc_nsectors;
613 	lp->d_ncylinders = sc->sc_ncylinders;
614 	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;
615 	lp->d_type = DTYPE_LD;
616 	strcpy(lp->d_typename, "unknown");
617 	strcpy(lp->d_packname, "fictitious");
618 	lp->d_secperunit = sc->sc_secperunit;
619 	lp->d_rpm = 7200;
620 	lp->d_interleave = 1;
621 	lp->d_flags = 0;
622 
623 	lp->d_partitions[RAW_PART].p_offset = 0;
624 	lp->d_partitions[RAW_PART].p_size =
625 	    lp->d_secperunit * (lp->d_secsize / DEV_BSIZE);
626 	lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
627 	lp->d_npartitions = RAW_PART + 1;
628 
629 	lp->d_magic = DISKMAGIC;
630 	lp->d_magic2 = DISKMAGIC;
631 	lp->d_checksum = dkcksum(lp);
632 }
633 
634 /*
635  * Wait interruptibly for an exclusive lock.
636  *
637  * XXX Several drivers do this; it should be abstracted and made MP-safe.
638  */
639 static int
640 ldlock(struct ld_softc *sc)
641 {
642 	int error;
643 
644 	while ((sc->sc_flags & LDF_LKHELD) != 0) {
645 		sc->sc_flags |= LDF_LKWANTED;
646 		if ((error = tsleep(sc, PRIBIO | PCATCH, "ldlck", 0)) != 0)
647 			return (error);
648 	}
649 	sc->sc_flags |= LDF_LKHELD;
650 	return (0);
651 }
652 
653 /*
654  * Unlock and wake up any waiters.
655  */
656 static void
657 ldunlock(struct ld_softc *sc)
658 {
659 
660 	sc->sc_flags &= ~LDF_LKHELD;
661 	if ((sc->sc_flags & LDF_LKWANTED) != 0) {
662 		sc->sc_flags &= ~LDF_LKWANTED;
663 		wakeup(sc);
664 	}
665 }
666 
667 /*
668  * Take a dump.
669  */
670 int
671 lddump(dev_t dev, daddr_t blkno, caddr_t va, size_t size)
672 {
673 	struct ld_softc *sc;
674 	struct disklabel *lp;
675 	int unit, part, nsects, sectoff, towrt, nblk, maxblkcnt, rv;
676 	static int dumping;
677 
678 	unit = DISKUNIT(dev);
679 	if ((sc = device_lookup(&ld_cd, unit)) == NULL)
680 		return (ENXIO);
681 	if ((sc->sc_flags & LDF_ENABLED) == 0)
682 		return (ENODEV);
683 	if (sc->sc_dump == NULL)
684 		return (ENXIO);
685 
686 	/* Check if recursive dump; if so, punt. */
687 	if (dumping)
688 		return (EFAULT);
689 	dumping = 1;
690 
691 	/* Convert to disk sectors.  Request must be a multiple of size. */
692 	part = DISKPART(dev);
693 	lp = sc->sc_dk.dk_label;
694 	if ((size % lp->d_secsize) != 0)
695 		return (EFAULT);
696 	towrt = size / lp->d_secsize;
697 	blkno = dbtob(blkno) / lp->d_secsize;	/* blkno in DEV_BSIZE units */
698 
699 	nsects = lp->d_partitions[part].p_size;
700 	sectoff = lp->d_partitions[part].p_offset;
701 
702 	/* Check transfer bounds against partition size. */
703 	if ((blkno < 0) || ((blkno + towrt) > nsects))
704 		return (EINVAL);
705 
706 	/* Offset block number to start of partition. */
707 	blkno += sectoff;
708 
709 	/* Start dumping and return when done. */
710 	maxblkcnt = sc->sc_maxxfer / sc->sc_secsize - 1;
711 	while (towrt > 0) {
712 		nblk = min(maxblkcnt, towrt);
713 
714 		if ((rv = (*sc->sc_dump)(sc, va, blkno, nblk)) != 0)
715 			return (rv);
716 
717 		towrt -= nblk;
718 		blkno += nblk;
719 		va += nblk * sc->sc_secsize;
720 	}
721 
722 	dumping = 0;
723 	return (0);
724 }
725 
726 /*
727  * Adjust the size of a transfer.
728  */
729 static void
730 ldminphys(struct buf *bp)
731 {
732 	struct ld_softc *sc;
733 
734 	sc = device_lookup(&ld_cd, DISKUNIT(bp->b_dev));
735 
736 	if (bp->b_bcount > sc->sc_maxxfer)
737 		bp->b_bcount = sc->sc_maxxfer;
738 	minphys(bp);
739 }
740