xref: /netbsd-src/sys/dev/ld.c (revision f89f6560d453f5e37386cc7938c072d2f528b9fa)
1 /*	$NetBSD: ld.c,v 1.82 2015/04/13 16:33:23 riastradh 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  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * Disk driver for use by RAID controllers.
34  */
35 
36 #include <sys/cdefs.h>
37 __KERNEL_RCSID(0, "$NetBSD: ld.c,v 1.82 2015/04/13 16:33:23 riastradh Exp $");
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/kernel.h>
42 #include <sys/device.h>
43 #include <sys/queue.h>
44 #include <sys/proc.h>
45 #include <sys/buf.h>
46 #include <sys/bufq.h>
47 #include <sys/endian.h>
48 #include <sys/disklabel.h>
49 #include <sys/disk.h>
50 #include <sys/dkio.h>
51 #include <sys/stat.h>
52 #include <sys/conf.h>
53 #include <sys/fcntl.h>
54 #include <sys/vnode.h>
55 #include <sys/syslog.h>
56 #include <sys/mutex.h>
57 #include <sys/rndsource.h>
58 
59 #include <dev/ldvar.h>
60 
61 #include <prop/proplib.h>
62 
63 static void	ldgetdefaultlabel(struct ld_softc *, struct disklabel *);
64 static void	ldgetdisklabel(struct ld_softc *);
65 static void	ldminphys(struct buf *bp);
66 static bool	ld_suspend(device_t, const pmf_qual_t *);
67 static bool	ld_shutdown(device_t, int);
68 static void	ldstart(struct ld_softc *, struct buf *);
69 static void	ld_set_geometry(struct ld_softc *);
70 static void	ld_config_interrupts (device_t);
71 static int	ldlastclose(device_t);
72 
73 extern struct	cfdriver ld_cd;
74 
75 static dev_type_open(ldopen);
76 static dev_type_close(ldclose);
77 static dev_type_read(ldread);
78 static dev_type_write(ldwrite);
79 static dev_type_ioctl(ldioctl);
80 static dev_type_strategy(ldstrategy);
81 static dev_type_dump(lddump);
82 static dev_type_size(ldsize);
83 
84 const struct bdevsw ld_bdevsw = {
85 	.d_open = ldopen,
86 	.d_close = ldclose,
87 	.d_strategy = ldstrategy,
88 	.d_ioctl = ldioctl,
89 	.d_dump = lddump,
90 	.d_psize = ldsize,
91 	.d_discard = nodiscard,
92 	.d_flag = D_DISK
93 };
94 
95 const struct cdevsw ld_cdevsw = {
96 	.d_open = ldopen,
97 	.d_close = ldclose,
98 	.d_read = ldread,
99 	.d_write = ldwrite,
100 	.d_ioctl = ldioctl,
101 	.d_stop = nostop,
102 	.d_tty = notty,
103 	.d_poll = nopoll,
104 	.d_mmap = nommap,
105 	.d_kqfilter = nokqfilter,
106 	.d_discard = nodiscard,
107 	.d_flag = D_DISK
108 };
109 
110 static struct	dkdriver lddkdriver = { ldstrategy, ldminphys };
111 
112 void
113 ldattach(struct ld_softc *sc)
114 {
115 	char tbuf[9];
116 
117 	mutex_init(&sc->sc_mutex, MUTEX_DEFAULT, IPL_VM);
118 
119 	if ((sc->sc_flags & LDF_ENABLED) == 0) {
120 		aprint_normal_dev(sc->sc_dv, "disabled\n");
121 		return;
122 	}
123 
124 	/* Initialise and attach the disk structure. */
125 	disk_init(&sc->sc_dk, device_xname(sc->sc_dv), &lddkdriver);
126 	disk_attach(&sc->sc_dk);
127 
128 	if (sc->sc_maxxfer > MAXPHYS)
129 		sc->sc_maxxfer = MAXPHYS;
130 
131 	/* Build synthetic geometry if necessary. */
132 	if (sc->sc_nheads == 0 || sc->sc_nsectors == 0 ||
133 	    sc->sc_ncylinders == 0) {
134 		uint64_t ncyl;
135 
136 		if (sc->sc_secperunit <= 528 * 2048)		/* 528MB */
137 			sc->sc_nheads = 16;
138 		else if (sc->sc_secperunit <= 1024 * 2048)	/* 1GB */
139 			sc->sc_nheads = 32;
140 		else if (sc->sc_secperunit <= 21504 * 2048)	/* 21GB */
141 			sc->sc_nheads = 64;
142 		else if (sc->sc_secperunit <= 43008 * 2048)	/* 42GB */
143 			sc->sc_nheads = 128;
144 		else
145 			sc->sc_nheads = 255;
146 
147 		sc->sc_nsectors = 63;
148 		sc->sc_ncylinders = INT_MAX;
149 		ncyl = sc->sc_secperunit /
150 		    (sc->sc_nheads * sc->sc_nsectors);
151 		if (ncyl < INT_MAX)
152 			sc->sc_ncylinders = (int)ncyl;
153 	}
154 
155 	format_bytes(tbuf, sizeof(tbuf), sc->sc_secperunit *
156 	    sc->sc_secsize);
157 	aprint_normal_dev(sc->sc_dv, "%s, %d cyl, %d head, %d sec, "
158 	    "%d bytes/sect x %"PRIu64" sectors\n",
159 	    tbuf, sc->sc_ncylinders, sc->sc_nheads,
160 	    sc->sc_nsectors, sc->sc_secsize, sc->sc_secperunit);
161 	sc->sc_disksize512 = sc->sc_secperunit * sc->sc_secsize / DEV_BSIZE;
162 
163 	ld_set_geometry(sc);
164 
165 	/* Attach the device into the rnd source list. */
166 	rnd_attach_source(&sc->sc_rnd_source, device_xname(sc->sc_dv),
167 	    RND_TYPE_DISK, RND_FLAG_DEFAULT);
168 
169 	/* Register with PMF */
170 	if (!pmf_device_register1(sc->sc_dv, ld_suspend, NULL, ld_shutdown))
171 		aprint_error_dev(sc->sc_dv,
172 		    "couldn't establish power handler\n");
173 
174 	bufq_alloc(&sc->sc_bufq, BUFQ_DISK_DEFAULT_STRAT, BUFQ_SORT_RAWBLOCK);
175 
176 	/* Discover wedges on this disk. */
177 	config_interrupts(sc->sc_dv, ld_config_interrupts);
178 }
179 
180 int
181 ldadjqparam(struct ld_softc *sc, int xmax)
182 {
183 	int s;
184 
185 	s = splbio();
186 	sc->sc_maxqueuecnt = xmax;
187 	splx(s);
188 
189 	return (0);
190 }
191 
192 int
193 ldbegindetach(struct ld_softc *sc, int flags)
194 {
195 	int s, rv = 0;
196 
197 	if ((sc->sc_flags & LDF_ENABLED) == 0)
198 		return (0);
199 
200 	rv = disk_begindetach(&sc->sc_dk, ldlastclose, sc->sc_dv, flags);
201 
202 	if (rv != 0)
203 		return rv;
204 
205 	s = splbio();
206 	sc->sc_maxqueuecnt = 0;
207 	sc->sc_flags |= LDF_DETACH;
208 	while (sc->sc_queuecnt > 0) {
209 		sc->sc_flags |= LDF_DRAIN;
210 		rv = tsleep(&sc->sc_queuecnt, PRIBIO, "lddrn", 0);
211 		if (rv)
212 			break;
213 	}
214 	splx(s);
215 
216 	return (rv);
217 }
218 
219 void
220 ldenddetach(struct ld_softc *sc)
221 {
222 	int s, bmaj, cmaj, i, mn;
223 
224 	if ((sc->sc_flags & LDF_ENABLED) == 0)
225 		return;
226 
227 	/* Wait for commands queued with the hardware to complete. */
228 	if (sc->sc_queuecnt != 0)
229 		if (tsleep(&sc->sc_queuecnt, PRIBIO, "lddtch", 30 * hz))
230 			printf("%s: not drained\n", device_xname(sc->sc_dv));
231 
232 	/* Locate the major numbers. */
233 	bmaj = bdevsw_lookup_major(&ld_bdevsw);
234 	cmaj = cdevsw_lookup_major(&ld_cdevsw);
235 
236 	/* Kill off any queued buffers. */
237 	s = splbio();
238 	bufq_drain(sc->sc_bufq);
239 	splx(s);
240 
241 	bufq_free(sc->sc_bufq);
242 
243 	/* Nuke the vnodes for any open instances. */
244 	for (i = 0; i < MAXPARTITIONS; i++) {
245 		mn = DISKMINOR(device_unit(sc->sc_dv), i);
246 		vdevgone(bmaj, mn, mn, VBLK);
247 		vdevgone(cmaj, mn, mn, VCHR);
248 	}
249 
250 	/* Delete all of our wedges. */
251 	dkwedge_delall(&sc->sc_dk);
252 
253 	/* Detach from the disk list. */
254 	disk_detach(&sc->sc_dk);
255 	disk_destroy(&sc->sc_dk);
256 
257 	/* Unhook the entropy source. */
258 	rnd_detach_source(&sc->sc_rnd_source);
259 
260 	/* Deregister with PMF */
261 	pmf_device_deregister(sc->sc_dv);
262 
263 	/*
264 	 * XXX We can't really flush the cache here, beceause the
265 	 * XXX device may already be non-existent from the controller's
266 	 * XXX perspective.
267 	 */
268 #if 0
269 	/* Flush the device's cache. */
270 	if (sc->sc_flush != NULL)
271 		if ((*sc->sc_flush)(sc, 0) != 0)
272 			aprint_error_dev(sc->sc_dv, "unable to flush cache\n");
273 #endif
274 	mutex_destroy(&sc->sc_mutex);
275 }
276 
277 /* ARGSUSED */
278 static bool
279 ld_suspend(device_t dev, const pmf_qual_t *qual)
280 {
281 	return ld_shutdown(dev, 0);
282 }
283 
284 /* ARGSUSED */
285 static bool
286 ld_shutdown(device_t dev, int flags)
287 {
288 	struct ld_softc *sc = device_private(dev);
289 
290 	if (sc->sc_flush != NULL && (*sc->sc_flush)(sc, LDFL_POLL) != 0) {
291 		printf("%s: unable to flush cache\n", device_xname(dev));
292 		return false;
293 	}
294 
295 	return true;
296 }
297 
298 /* ARGSUSED */
299 static int
300 ldopen(dev_t dev, int flags, int fmt, struct lwp *l)
301 {
302 	struct ld_softc *sc;
303 	int error, unit, part;
304 
305 	unit = DISKUNIT(dev);
306 	if ((sc = device_lookup_private(&ld_cd, unit)) == NULL)
307 		return (ENXIO);
308 	if ((sc->sc_flags & LDF_ENABLED) == 0)
309 		return (ENODEV);
310 	part = DISKPART(dev);
311 
312 	mutex_enter(&sc->sc_dk.dk_openlock);
313 
314 	if (sc->sc_dk.dk_openmask == 0) {
315 		/* Load the partition info if not already loaded. */
316 		if ((sc->sc_flags & LDF_VLABEL) == 0)
317 			ldgetdisklabel(sc);
318 	}
319 
320 	/* Check that the partition exists. */
321 	if (part != RAW_PART && (part >= sc->sc_dk.dk_label->d_npartitions ||
322 	    sc->sc_dk.dk_label->d_partitions[part].p_fstype == FS_UNUSED)) {
323 		error = ENXIO;
324 		goto bad1;
325 	}
326 
327 	/* Ensure only one open at a time. */
328 	switch (fmt) {
329 	case S_IFCHR:
330 		sc->sc_dk.dk_copenmask |= (1 << part);
331 		break;
332 	case S_IFBLK:
333 		sc->sc_dk.dk_bopenmask |= (1 << part);
334 		break;
335 	}
336 	sc->sc_dk.dk_openmask =
337 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
338 
339 	error = 0;
340  bad1:
341 	mutex_exit(&sc->sc_dk.dk_openlock);
342 	return (error);
343 }
344 
345 static int
346 ldlastclose(device_t self)
347 {
348 	struct ld_softc *sc = device_private(self);
349 
350 	if (sc->sc_flush != NULL && (*sc->sc_flush)(sc, 0) != 0)
351 		aprint_error_dev(self, "unable to flush cache\n");
352 	if ((sc->sc_flags & LDF_KLABEL) == 0)
353 		sc->sc_flags &= ~LDF_VLABEL;
354 
355 	return 0;
356 }
357 
358 /* ARGSUSED */
359 static int
360 ldclose(dev_t dev, int flags, int fmt, struct lwp *l)
361 {
362 	struct ld_softc *sc;
363 	int part, unit;
364 
365 	unit = DISKUNIT(dev);
366 	part = DISKPART(dev);
367 	sc = device_lookup_private(&ld_cd, unit);
368 
369 	mutex_enter(&sc->sc_dk.dk_openlock);
370 
371 	switch (fmt) {
372 	case S_IFCHR:
373 		sc->sc_dk.dk_copenmask &= ~(1 << part);
374 		break;
375 	case S_IFBLK:
376 		sc->sc_dk.dk_bopenmask &= ~(1 << part);
377 		break;
378 	}
379 	sc->sc_dk.dk_openmask =
380 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
381 
382 	if (sc->sc_dk.dk_openmask == 0)
383 		ldlastclose(sc->sc_dv);
384 
385 	mutex_exit(&sc->sc_dk.dk_openlock);
386 	return (0);
387 }
388 
389 /* ARGSUSED */
390 static int
391 ldread(dev_t dev, struct uio *uio, int ioflag)
392 {
393 
394 	return (physio(ldstrategy, NULL, dev, B_READ, ldminphys, uio));
395 }
396 
397 /* ARGSUSED */
398 static int
399 ldwrite(dev_t dev, struct uio *uio, int ioflag)
400 {
401 
402 	return (physio(ldstrategy, NULL, dev, B_WRITE, ldminphys, uio));
403 }
404 
405 /* ARGSUSED */
406 static int
407 ldioctl(dev_t dev, u_long cmd, void *addr, int32_t flag, struct lwp *l)
408 {
409 	struct ld_softc *sc;
410 	int unit, error;
411 #ifdef __HAVE_OLD_DISKLABEL
412 	struct disklabel newlabel;
413 #endif
414 	struct disklabel *lp;
415 
416 	unit = DISKUNIT(dev);
417 	sc = device_lookup_private(&ld_cd, unit);
418 
419 	error = disk_ioctl(&sc->sc_dk, dev, cmd, addr, flag, l);
420 	if (error != EPASSTHROUGH)
421 		return (error);
422 
423 	error = 0;
424 	switch (cmd) {
425 	case DIOCWDINFO:
426 	case DIOCSDINFO:
427 #ifdef __HAVE_OLD_DISKLABEL
428 	case ODIOCWDINFO:
429 	case ODIOCSDINFO:
430 
431 		if (cmd == ODIOCSDINFO || cmd == ODIOCWDINFO) {
432 			memset(&newlabel, 0, sizeof newlabel);
433 			memcpy(&newlabel, addr, sizeof (struct olddisklabel));
434 			lp = &newlabel;
435 		} else
436 #endif
437 		lp = (struct disklabel *)addr;
438 
439 		if ((flag & FWRITE) == 0)
440 			return (EBADF);
441 
442 		mutex_enter(&sc->sc_dk.dk_openlock);
443 		sc->sc_flags |= LDF_LABELLING;
444 
445 		error = setdisklabel(sc->sc_dk.dk_label,
446 		    lp, /*sc->sc_dk.dk_openmask : */0,
447 		    sc->sc_dk.dk_cpulabel);
448 		if (error == 0 && (cmd == DIOCWDINFO
449 #ifdef __HAVE_OLD_DISKLABEL
450 		    || cmd == ODIOCWDINFO
451 #endif
452 		    ))
453 			error = writedisklabel(
454 			    MAKEDISKDEV(major(dev), DISKUNIT(dev), RAW_PART),
455 			    ldstrategy, sc->sc_dk.dk_label,
456 			    sc->sc_dk.dk_cpulabel);
457 
458 		sc->sc_flags &= ~LDF_LABELLING;
459 		mutex_exit(&sc->sc_dk.dk_openlock);
460 		break;
461 
462 	case DIOCKLABEL:
463 		if ((flag & FWRITE) == 0)
464 			return (EBADF);
465 		if (*(int *)addr)
466 			sc->sc_flags |= LDF_KLABEL;
467 		else
468 			sc->sc_flags &= ~LDF_KLABEL;
469 		break;
470 
471 	case DIOCWLABEL:
472 		if ((flag & FWRITE) == 0)
473 			return (EBADF);
474 		if (*(int *)addr)
475 			sc->sc_flags |= LDF_WLABEL;
476 		else
477 			sc->sc_flags &= ~LDF_WLABEL;
478 		break;
479 
480 	case DIOCGDEFLABEL:
481 		ldgetdefaultlabel(sc, (struct disklabel *)addr);
482 		break;
483 
484 #ifdef __HAVE_OLD_DISKLABEL
485 	case ODIOCGDEFLABEL:
486 		ldgetdefaultlabel(sc, &newlabel);
487 		if (newlabel.d_npartitions > OLDMAXPARTITIONS)
488 			return ENOTTY;
489 		memcpy(addr, &newlabel, sizeof (struct olddisklabel));
490 		break;
491 #endif
492 
493 	case DIOCCACHESYNC:
494 		/*
495 		 * XXX Do we really need to care about having a writable
496 		 * file descriptor here?
497 		 */
498 		if ((flag & FWRITE) == 0)
499 			error = EBADF;
500 		else if (sc->sc_flush)
501 			error = (*sc->sc_flush)(sc, 0);
502 		else
503 			error = 0;	/* XXX Error out instead? */
504 		break;
505 
506 	case DIOCGSTRATEGY:
507 	    {
508 		struct disk_strategy *dks = (void *)addr;
509 
510 		mutex_enter(&sc->sc_mutex);
511 		strlcpy(dks->dks_name, bufq_getstrategyname(sc->sc_bufq),
512 		    sizeof(dks->dks_name));
513 		mutex_exit(&sc->sc_mutex);
514 		dks->dks_paramlen = 0;
515 
516 		return 0;
517 	    }
518 	case DIOCSSTRATEGY:
519 	    {
520 		struct disk_strategy *dks = (void *)addr;
521 		struct bufq_state *new_bufq, *old_bufq;
522 
523 		if ((flag & FWRITE) == 0)
524 			return EPERM;
525 
526 		if (dks->dks_param != NULL)
527 			return EINVAL;
528 
529 		dks->dks_name[sizeof(dks->dks_name) - 1] = 0; /* ensure term */
530 		error = bufq_alloc(&new_bufq, dks->dks_name,
531 		    BUFQ_EXACT|BUFQ_SORT_RAWBLOCK);
532 		if (error)
533 			return error;
534 
535 		mutex_enter(&sc->sc_mutex);
536 		old_bufq = sc->sc_bufq;
537 		bufq_move(new_bufq, old_bufq);
538 		sc->sc_bufq = new_bufq;
539 		mutex_exit(&sc->sc_mutex);
540 		bufq_free(old_bufq);
541 
542 		return 0;
543 	    }
544 	default:
545 		error = ENOTTY;
546 		break;
547 	}
548 
549 	return (error);
550 }
551 
552 static void
553 ldstrategy(struct buf *bp)
554 {
555 	struct ld_softc *sc;
556 	struct disklabel *lp;
557 	daddr_t blkno;
558 	int s, part;
559 
560 	sc = device_lookup_private(&ld_cd, DISKUNIT(bp->b_dev));
561 	part = DISKPART(bp->b_dev);
562 
563 	if ((sc->sc_flags & LDF_DETACH) != 0) {
564 		bp->b_error = EIO;
565 		goto done;
566 	}
567 
568 	lp = sc->sc_dk.dk_label;
569 
570 	/*
571 	 * The transfer must be a whole number of blocks and the offset must
572 	 * not be negative.
573 	 */
574 	if ((bp->b_bcount % lp->d_secsize) != 0 || bp->b_blkno < 0) {
575 		bp->b_error = EINVAL;
576 		goto done;
577 	}
578 
579 	/* If it's a null transfer, return immediately. */
580 	if (bp->b_bcount == 0)
581 		goto done;
582 
583 	/*
584 	 * Do bounds checking and adjust the transfer.  If error, process.
585 	 * If past the end of partition, just return.
586 	 */
587 	if (part == RAW_PART) {
588 		if (bounds_check_with_mediasize(bp, DEV_BSIZE,
589 		    sc->sc_disksize512) <= 0)
590 			goto done;
591 	} else {
592 		if (bounds_check_with_label(&sc->sc_dk, bp,
593 		    (sc->sc_flags & (LDF_WLABEL | LDF_LABELLING)) != 0) <= 0)
594 			goto done;
595 	}
596 
597 	/*
598 	 * Convert the block number to absolute and put it in terms
599 	 * of the device's logical block size.
600 	 */
601 	if (lp->d_secsize == DEV_BSIZE)
602 		blkno = bp->b_blkno;
603 	else if (lp->d_secsize > DEV_BSIZE)
604 		blkno = bp->b_blkno / (lp->d_secsize / DEV_BSIZE);
605 	else
606 		blkno = bp->b_blkno * (DEV_BSIZE / lp->d_secsize);
607 
608 	if (part != RAW_PART)
609 		blkno += lp->d_partitions[part].p_offset;
610 
611 	bp->b_rawblkno = blkno;
612 
613 	s = splbio();
614 	ldstart(sc, bp);
615 	splx(s);
616 	return;
617 
618  done:
619 	bp->b_resid = bp->b_bcount;
620 	biodone(bp);
621 }
622 
623 static void
624 ldstart(struct ld_softc *sc, struct buf *bp)
625 {
626 	int error;
627 
628 	mutex_enter(&sc->sc_mutex);
629 
630 	if (bp != NULL)
631 		bufq_put(sc->sc_bufq, bp);
632 
633 	while (sc->sc_queuecnt < sc->sc_maxqueuecnt) {
634 		/* See if there is work to do. */
635 		if ((bp = bufq_peek(sc->sc_bufq)) == NULL)
636 			break;
637 
638 		disk_busy(&sc->sc_dk);
639 		sc->sc_queuecnt++;
640 
641 		if (__predict_true((error = (*sc->sc_start)(sc, bp)) == 0)) {
642 			/*
643 			 * The back-end is running the job; remove it from
644 			 * the queue.
645 			 */
646 			(void) bufq_get(sc->sc_bufq);
647 		} else  {
648 			disk_unbusy(&sc->sc_dk, 0, (bp->b_flags & B_READ));
649 			sc->sc_queuecnt--;
650 			if (error == EAGAIN) {
651 				/*
652 				 * Temporary resource shortage in the
653 				 * back-end; just defer the job until
654 				 * later.
655 				 *
656 				 * XXX We might consider a watchdog timer
657 				 * XXX to make sure we are kicked into action.
658 				 */
659 				break;
660 			} else {
661 				(void) bufq_get(sc->sc_bufq);
662 				bp->b_error = error;
663 				bp->b_resid = bp->b_bcount;
664 				mutex_exit(&sc->sc_mutex);
665 				biodone(bp);
666 				mutex_enter(&sc->sc_mutex);
667 			}
668 		}
669 	}
670 
671 	mutex_exit(&sc->sc_mutex);
672 }
673 
674 void
675 lddone(struct ld_softc *sc, struct buf *bp)
676 {
677 
678 	if (bp->b_error != 0) {
679 		diskerr(bp, "ld", "error", LOG_PRINTF, 0, sc->sc_dk.dk_label);
680 		printf("\n");
681 	}
682 
683 	disk_unbusy(&sc->sc_dk, bp->b_bcount - bp->b_resid,
684 	    (bp->b_flags & B_READ));
685 	rnd_add_uint32(&sc->sc_rnd_source, bp->b_rawblkno);
686 	biodone(bp);
687 
688 	mutex_enter(&sc->sc_mutex);
689 	if (--sc->sc_queuecnt <= sc->sc_maxqueuecnt) {
690 		if ((sc->sc_flags & LDF_DRAIN) != 0) {
691 			sc->sc_flags &= ~LDF_DRAIN;
692 			wakeup(&sc->sc_queuecnt);
693 		}
694 		mutex_exit(&sc->sc_mutex);
695 		ldstart(sc, NULL);
696 	} else
697 		mutex_exit(&sc->sc_mutex);
698 }
699 
700 static int
701 ldsize(dev_t dev)
702 {
703 	struct ld_softc *sc;
704 	int part, unit, omask, size;
705 
706 	unit = DISKUNIT(dev);
707 	if ((sc = device_lookup_private(&ld_cd, unit)) == NULL)
708 		return (ENODEV);
709 	if ((sc->sc_flags & LDF_ENABLED) == 0)
710 		return (ENODEV);
711 	part = DISKPART(dev);
712 
713 	omask = sc->sc_dk.dk_openmask & (1 << part);
714 
715 	if (omask == 0 && ldopen(dev, 0, S_IFBLK, NULL) != 0)
716 		return (-1);
717 	else if (sc->sc_dk.dk_label->d_partitions[part].p_fstype != FS_SWAP)
718 		size = -1;
719 	else
720 		size = sc->sc_dk.dk_label->d_partitions[part].p_size *
721 		    (sc->sc_dk.dk_label->d_secsize / DEV_BSIZE);
722 	if (omask == 0 && ldclose(dev, 0, S_IFBLK, NULL) != 0)
723 		return (-1);
724 
725 	return (size);
726 }
727 
728 /*
729  * Load the label information from the specified device.
730  */
731 static void
732 ldgetdisklabel(struct ld_softc *sc)
733 {
734 	const char *errstring;
735 
736 	ldgetdefaultlabel(sc, sc->sc_dk.dk_label);
737 
738 	/* Call the generic disklabel extraction routine. */
739 	errstring = readdisklabel(MAKEDISKDEV(0, device_unit(sc->sc_dv),
740 	    RAW_PART), ldstrategy, sc->sc_dk.dk_label, sc->sc_dk.dk_cpulabel);
741 	if (errstring != NULL)
742 		printf("%s: %s\n", device_xname(sc->sc_dv), errstring);
743 
744 	/* In-core label now valid. */
745 	sc->sc_flags |= LDF_VLABEL;
746 }
747 
748 /*
749  * Construct a ficticious label.
750  */
751 static void
752 ldgetdefaultlabel(struct ld_softc *sc, struct disklabel *lp)
753 {
754 
755 	memset(lp, 0, sizeof(struct disklabel));
756 
757 	lp->d_secsize = sc->sc_secsize;
758 	lp->d_ntracks = sc->sc_nheads;
759 	lp->d_nsectors = sc->sc_nsectors;
760 	lp->d_ncylinders = sc->sc_ncylinders;
761 	lp->d_secpercyl = lp->d_ntracks * lp->d_nsectors;
762 	lp->d_type = DKTYPE_LD;
763 	strlcpy(lp->d_typename, "unknown", sizeof(lp->d_typename));
764 	strlcpy(lp->d_packname, "fictitious", sizeof(lp->d_packname));
765 	if (sc->sc_secperunit > UINT32_MAX)
766 		lp->d_secperunit = UINT32_MAX;
767 	else
768 		lp->d_secperunit = sc->sc_secperunit;
769 	lp->d_rpm = 7200;
770 	lp->d_interleave = 1;
771 	lp->d_flags = 0;
772 
773 	lp->d_partitions[RAW_PART].p_offset = 0;
774 	lp->d_partitions[RAW_PART].p_size = lp->d_secperunit;
775 	lp->d_partitions[RAW_PART].p_fstype = FS_UNUSED;
776 	lp->d_npartitions = RAW_PART + 1;
777 
778 	lp->d_magic = DISKMAGIC;
779 	lp->d_magic2 = DISKMAGIC;
780 	lp->d_checksum = dkcksum(lp);
781 }
782 
783 /*
784  * Take a dump.
785  */
786 static int
787 lddump(dev_t dev, daddr_t blkno, void *vav, size_t size)
788 {
789 	char *va = vav;
790 	struct ld_softc *sc;
791 	struct disklabel *lp;
792 	int unit, part, nsects, sectoff, towrt, nblk, maxblkcnt, rv;
793 	static int dumping;
794 
795 	unit = DISKUNIT(dev);
796 	if ((sc = device_lookup_private(&ld_cd, unit)) == NULL)
797 		return (ENXIO);
798 	if ((sc->sc_flags & LDF_ENABLED) == 0)
799 		return (ENODEV);
800 	if (sc->sc_dump == NULL)
801 		return (ENXIO);
802 
803 	/* Check if recursive dump; if so, punt. */
804 	if (dumping)
805 		return (EFAULT);
806 	dumping = 1;
807 
808 	/* Convert to disk sectors.  Request must be a multiple of size. */
809 	part = DISKPART(dev);
810 	lp = sc->sc_dk.dk_label;
811 	if ((size % lp->d_secsize) != 0)
812 		return (EFAULT);
813 	towrt = size / lp->d_secsize;
814 	blkno = dbtob(blkno) / lp->d_secsize;	/* blkno in DEV_BSIZE units */
815 
816 	nsects = lp->d_partitions[part].p_size;
817 	sectoff = lp->d_partitions[part].p_offset;
818 
819 	/* Check transfer bounds against partition size. */
820 	if ((blkno < 0) || ((blkno + towrt) > nsects))
821 		return (EINVAL);
822 
823 	/* Offset block number to start of partition. */
824 	blkno += sectoff;
825 
826 	/* Start dumping and return when done. */
827 	maxblkcnt = sc->sc_maxxfer / sc->sc_secsize - 1;
828 	while (towrt > 0) {
829 		nblk = min(maxblkcnt, towrt);
830 
831 		if ((rv = (*sc->sc_dump)(sc, va, blkno, nblk)) != 0)
832 			return (rv);
833 
834 		towrt -= nblk;
835 		blkno += nblk;
836 		va += nblk * sc->sc_secsize;
837 	}
838 
839 	dumping = 0;
840 	return (0);
841 }
842 
843 /*
844  * Adjust the size of a transfer.
845  */
846 static void
847 ldminphys(struct buf *bp)
848 {
849 	struct ld_softc *sc;
850 
851 	sc = device_lookup_private(&ld_cd, DISKUNIT(bp->b_dev));
852 
853 	if (bp->b_bcount > sc->sc_maxxfer)
854 		bp->b_bcount = sc->sc_maxxfer;
855 	minphys(bp);
856 }
857 
858 static void
859 ld_set_geometry(struct ld_softc *ld)
860 {
861 	struct disk_geom *dg = &ld->sc_dk.dk_geom;
862 
863 	memset(dg, 0, sizeof(*dg));
864 
865 	dg->dg_secperunit = ld->sc_secperunit;
866 	dg->dg_secsize = ld->sc_secsize;
867 	dg->dg_nsectors = ld->sc_nsectors;
868 	dg->dg_ntracks = ld->sc_nheads;
869 	dg->dg_ncylinders = ld->sc_ncylinders;
870 
871 	disk_set_info(ld->sc_dv, &ld->sc_dk, NULL);
872 }
873 
874 static void
875 ld_config_interrupts(device_t d)
876 {
877 	struct ld_softc *sc = device_private(d);
878 	dkwedge_discover(&sc->sc_dk);
879 }
880