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      1 /*	$NetBSD: dk.c,v 1.173 2025/04/13 14:01:00 jakllsch Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2004, 2005, 2006, 2007 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe.
      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 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.173 2025/04/13 14:01:00 jakllsch Exp $");
     34 
     35 #ifdef _KERNEL_OPT
     36 #include "opt_dkwedge.h"
     37 #endif
     38 
     39 #include <sys/param.h>
     40 #include <sys/types.h>
     41 
     42 #include <sys/buf.h>
     43 #include <sys/bufq.h>
     44 #include <sys/callout.h>
     45 #include <sys/conf.h>
     46 #include <sys/device.h>
     47 #include <sys/disk.h>
     48 #include <sys/disklabel.h>
     49 #include <sys/errno.h>
     50 #include <sys/fcntl.h>
     51 #include <sys/ioctl.h>
     52 #include <sys/kauth.h>
     53 #include <sys/kernel.h>
     54 #include <sys/malloc.h>
     55 #include <sys/pool.h>
     56 #include <sys/proc.h>
     57 #include <sys/rwlock.h>
     58 #include <sys/stat.h>
     59 #include <sys/systm.h>
     60 #include <sys/vnode.h>
     61 
     62 #include <miscfs/specfs/specdev.h>
     63 
     64 MALLOC_DEFINE(M_DKWEDGE, "dkwedge", "Disk wedge structures");
     65 
     66 typedef enum {
     67 	DKW_STATE_LARVAL	= 0,
     68 	DKW_STATE_RUNNING	= 1,
     69 	DKW_STATE_DYING		= 2,
     70 	DKW_STATE_DEAD		= 666
     71 } dkwedge_state_t;
     72 
     73 /*
     74  * Lock order:
     75  *
     76  *	sc->sc_dk.dk_openlock
     77  *	=> sc->sc_parent->dk_rawlock
     78  *	=> sc->sc_parent->dk_openlock
     79  *	=> dkwedges_lock
     80  *	=> sc->sc_sizelock
     81  *
     82  * Locking notes:
     83  *
     84  *	W	dkwedges_lock
     85  *	D	device reference
     86  *	O	sc->sc_dk.dk_openlock
     87  *	P	sc->sc_parent->dk_openlock
     88  *	R	sc->sc_parent->dk_rawlock
     89  *	S	sc->sc_sizelock
     90  *	I	sc->sc_iolock
     91  *	$	stable after initialization
     92  *	1	used only by a single thread
     93  *
     94  * x&y means both x and y must be held to write (with a write lock if
     95  * one is rwlock), and either x or y must be held to read.
     96  */
     97 
     98 struct dkwedge_softc {
     99 	device_t	sc_dev;	/* P&W: pointer to our pseudo-device */
    100 		/* sc_dev is also stable while device is referenced */
    101 	struct cfdata	sc_cfdata;	/* 1: our cfdata structure */
    102 	uint8_t		sc_wname[128];	/* $: wedge name (Unicode, UTF-8) */
    103 
    104 	dkwedge_state_t sc_state;	/* state this wedge is in */
    105 		/* stable while device is referenced */
    106 		/* used only in assertions when stable, and in dump in ddb */
    107 
    108 	struct disk	*sc_parent;	/* $: parent disk */
    109 		/* P: sc_parent->dk_openmask */
    110 		/* P: sc_parent->dk_nwedges */
    111 		/* P: sc_parent->dk_wedges */
    112 		/* R: sc_parent->dk_rawopens */
    113 		/* R: sc_parent->dk_rawvp (also stable while wedge is open) */
    114 	daddr_t		sc_offset;	/* $: LBA offset of wedge in parent */
    115 	krwlock_t	sc_sizelock;
    116 	uint64_t	sc_size;	/* S: size of wedge in blocks */
    117 	char		sc_ptype[32];	/* $: partition type */
    118 	dev_t		sc_pdev;	/* $: cached parent's dev_t */
    119 					/* P: link on parent's wedge list */
    120 	LIST_ENTRY(dkwedge_softc) sc_plink;
    121 
    122 	struct disk	sc_dk;		/* our own disk structure */
    123 		/* O&R: sc_dk.dk_bopenmask */
    124 		/* O&R: sc_dk.dk_copenmask */
    125 		/* O&R: sc_dk.dk_openmask */
    126 	struct bufq_state *sc_bufq;	/* $: buffer queue */
    127 	struct callout	sc_restart_ch;	/* I: callout to restart I/O */
    128 
    129 	kmutex_t	sc_iolock;
    130 	bool		sc_iostop;	/* I: don't schedule restart */
    131 	int		sc_mode;	/* O&R: parent open mode */
    132 };
    133 
    134 static int	dkwedge_match(device_t, cfdata_t, void *);
    135 static void	dkwedge_attach(device_t, device_t, void *);
    136 static int	dkwedge_detach(device_t, int);
    137 
    138 static void	dk_set_geometry(struct dkwedge_softc *, struct disk *);
    139 
    140 static void	dkstart(struct dkwedge_softc *);
    141 static void	dkiodone(struct buf *);
    142 static void	dkrestart(void *);
    143 static void	dkminphys(struct buf *);
    144 
    145 static int	dkfirstopen(struct dkwedge_softc *, int);
    146 static void	dklastclose(struct dkwedge_softc *);
    147 static int	dkwedge_detach(device_t, int);
    148 static void	dkwedge_delall1(struct disk *, bool);
    149 static int	dkwedge_del1(struct dkwedge_info *, int);
    150 static int	dk_open_parent(dev_t, int, struct vnode **);
    151 static int	dk_close_parent(struct vnode *, int);
    152 
    153 static dev_type_open(dkopen);
    154 static dev_type_close(dkclose);
    155 static dev_type_cancel(dkcancel);
    156 static dev_type_read(dkread);
    157 static dev_type_write(dkwrite);
    158 static dev_type_ioctl(dkioctl);
    159 static dev_type_strategy(dkstrategy);
    160 static dev_type_dump(dkdump);
    161 static dev_type_size(dksize);
    162 static dev_type_discard(dkdiscard);
    163 
    164 CFDRIVER_DECL(dk, DV_DISK, NULL);
    165 CFATTACH_DECL3_NEW(dk, 0,
    166     dkwedge_match, dkwedge_attach, dkwedge_detach, NULL, NULL, NULL,
    167     DVF_DETACH_SHUTDOWN);
    168 
    169 const struct bdevsw dk_bdevsw = {
    170 	.d_open = dkopen,
    171 	.d_close = dkclose,
    172 	.d_cancel = dkcancel,
    173 	.d_strategy = dkstrategy,
    174 	.d_ioctl = dkioctl,
    175 	.d_dump = dkdump,
    176 	.d_psize = dksize,
    177 	.d_discard = dkdiscard,
    178 	.d_cfdriver = &dk_cd,
    179 	.d_devtounit = dev_minor_unit,
    180 	.d_flag = D_DISK | D_MPSAFE
    181 };
    182 
    183 const struct cdevsw dk_cdevsw = {
    184 	.d_open = dkopen,
    185 	.d_close = dkclose,
    186 	.d_cancel = dkcancel,
    187 	.d_read = dkread,
    188 	.d_write = dkwrite,
    189 	.d_ioctl = dkioctl,
    190 	.d_stop = nostop,
    191 	.d_tty = notty,
    192 	.d_poll = nopoll,
    193 	.d_mmap = nommap,
    194 	.d_kqfilter = nokqfilter,
    195 	.d_discard = dkdiscard,
    196 	.d_cfdriver = &dk_cd,
    197 	.d_devtounit = dev_minor_unit,
    198 	.d_flag = D_DISK | D_MPSAFE
    199 };
    200 
    201 static struct dkwedge_softc **dkwedges;
    202 static u_int ndkwedges;
    203 static krwlock_t dkwedges_lock;
    204 
    205 static LIST_HEAD(, dkwedge_discovery_method) dkwedge_discovery_methods;
    206 static krwlock_t dkwedge_discovery_methods_lock;
    207 
    208 /*
    209  * dkwedge_match:
    210  *
    211  *	Autoconfiguration match function for pseudo-device glue.
    212  */
    213 static int
    214 dkwedge_match(device_t parent, cfdata_t match, void *aux)
    215 {
    216 
    217 	/* Pseudo-device; always present. */
    218 	return 1;
    219 }
    220 
    221 /*
    222  * dkwedge_attach:
    223  *
    224  *	Autoconfiguration attach function for pseudo-device glue.
    225  */
    226 static void
    227 dkwedge_attach(device_t parent, device_t self, void *aux)
    228 {
    229 	struct dkwedge_softc *sc = aux;
    230 	struct disk *pdk = sc->sc_parent;
    231 	int unit = device_unit(self);
    232 
    233 	KASSERTMSG(unit >= 0, "unit=%d", unit);
    234 
    235 	if (!pmf_device_register(self, NULL, NULL))
    236 		aprint_error_dev(self, "couldn't establish power handler\n");
    237 
    238 	mutex_enter(&pdk->dk_openlock);
    239 	rw_enter(&dkwedges_lock, RW_WRITER);
    240 	KASSERTMSG(unit < ndkwedges, "unit=%d ndkwedges=%u", unit, ndkwedges);
    241 	KASSERTMSG(sc == dkwedges[unit], "sc=%p dkwedges[%d]=%p",
    242 	    sc, unit, dkwedges[unit]);
    243 	KASSERTMSG(sc->sc_dev == NULL, "sc=%p sc->sc_dev=%p", sc, sc->sc_dev);
    244 	sc->sc_dev = self;
    245 	rw_exit(&dkwedges_lock);
    246 	mutex_exit(&pdk->dk_openlock);
    247 
    248 	disk_init(&sc->sc_dk, device_xname(sc->sc_dev), NULL);
    249 	mutex_enter(&pdk->dk_openlock);
    250 	dk_set_geometry(sc, pdk);
    251 	mutex_exit(&pdk->dk_openlock);
    252 	disk_attach(&sc->sc_dk);
    253 
    254 	/* Disk wedge is ready for use! */
    255 	device_set_private(self, sc);
    256 	sc->sc_state = DKW_STATE_RUNNING;
    257 }
    258 
    259 /*
    260  * dkwedge_compute_pdev:
    261  *
    262  *	Compute the parent disk's dev_t.
    263  */
    264 static int
    265 dkwedge_compute_pdev(const char *pname, dev_t *pdevp, enum vtype type)
    266 {
    267 	const char *name, *cp;
    268 	devmajor_t pmaj;
    269 	int punit;
    270 	char devname[16];
    271 
    272 	name = pname;
    273 	switch (type) {
    274 	case VBLK:
    275 		pmaj = devsw_name2blk(name, devname, sizeof(devname));
    276 		break;
    277 	case VCHR:
    278 		pmaj = devsw_name2chr(name, devname, sizeof(devname));
    279 		break;
    280 	default:
    281 		pmaj = NODEVMAJOR;
    282 		break;
    283 	}
    284 	if (pmaj == NODEVMAJOR)
    285 		return ENXIO;
    286 
    287 	name += strlen(devname);
    288 	for (cp = name, punit = 0; *cp >= '0' && *cp <= '9'; cp++)
    289 		punit = (punit * 10) + (*cp - '0');
    290 	if (cp == name) {
    291 		/* Invalid parent disk name. */
    292 		return ENXIO;
    293 	}
    294 
    295 	*pdevp = MAKEDISKDEV(pmaj, punit, RAW_PART);
    296 
    297 	return 0;
    298 }
    299 
    300 /*
    301  * dkwedge_array_expand:
    302  *
    303  *	Expand the dkwedges array.
    304  *
    305  *	Releases and reacquires dkwedges_lock as a writer.
    306  */
    307 static int
    308 dkwedge_array_expand(void)
    309 {
    310 
    311 	const unsigned incr = 16;
    312 	unsigned newcnt, oldcnt;
    313 	struct dkwedge_softc **newarray = NULL, **oldarray = NULL;
    314 
    315 	KASSERT(rw_write_held(&dkwedges_lock));
    316 
    317 	oldcnt = ndkwedges;
    318 	oldarray = dkwedges;
    319 
    320 	if (oldcnt >= INT_MAX - incr)
    321 		return ENFILE;	/* XXX */
    322 	newcnt = oldcnt + incr;
    323 
    324 	rw_exit(&dkwedges_lock);
    325 	newarray = malloc(newcnt * sizeof(*newarray), M_DKWEDGE,
    326 	    M_WAITOK|M_ZERO);
    327 	rw_enter(&dkwedges_lock, RW_WRITER);
    328 
    329 	if (ndkwedges != oldcnt || dkwedges != oldarray) {
    330 		oldarray = NULL; /* already recycled */
    331 		goto out;
    332 	}
    333 
    334 	if (oldarray != NULL)
    335 		memcpy(newarray, dkwedges, ndkwedges * sizeof(*newarray));
    336 	dkwedges = newarray;
    337 	newarray = NULL;	/* transferred to dkwedges */
    338 	ndkwedges = newcnt;
    339 
    340 out:	rw_exit(&dkwedges_lock);
    341 	if (oldarray != NULL)
    342 		free(oldarray, M_DKWEDGE);
    343 	if (newarray != NULL)
    344 		free(newarray, M_DKWEDGE);
    345 	rw_enter(&dkwedges_lock, RW_WRITER);
    346 	return 0;
    347 }
    348 
    349 static void
    350 dkwedge_size_init(struct dkwedge_softc *sc, uint64_t size)
    351 {
    352 
    353 	rw_init(&sc->sc_sizelock);
    354 	sc->sc_size = size;
    355 }
    356 
    357 static void
    358 dkwedge_size_fini(struct dkwedge_softc *sc)
    359 {
    360 
    361 	rw_destroy(&sc->sc_sizelock);
    362 }
    363 
    364 static uint64_t
    365 dkwedge_size(struct dkwedge_softc *sc)
    366 {
    367 	uint64_t size;
    368 
    369 	rw_enter(&sc->sc_sizelock, RW_READER);
    370 	size = sc->sc_size;
    371 	rw_exit(&sc->sc_sizelock);
    372 
    373 	return size;
    374 }
    375 
    376 static void
    377 dkwedge_size_increase(struct dkwedge_softc *sc, uint64_t size)
    378 {
    379 
    380 	KASSERT(mutex_owned(&sc->sc_parent->dk_openlock));
    381 
    382 	rw_enter(&sc->sc_sizelock, RW_WRITER);
    383 	KASSERTMSG(size >= sc->sc_size,
    384 	    "decreasing dkwedge size from %"PRIu64" to %"PRIu64,
    385 	    sc->sc_size, size);
    386 	sc->sc_size = size;
    387 	rw_exit(&sc->sc_sizelock);
    388 }
    389 
    390 static void
    391 dk_set_geometry(struct dkwedge_softc *sc, struct disk *pdk)
    392 {
    393 	struct disk *dk = &sc->sc_dk;
    394 	struct disk_geom *dg = &dk->dk_geom;
    395 	uint32_t r, lspps;
    396 
    397 	KASSERT(mutex_owned(&pdk->dk_openlock));
    398 
    399 	memset(dg, 0, sizeof(*dg));
    400 
    401 	dg->dg_secperunit = dkwedge_size(sc);
    402 	dg->dg_secsize = DEV_BSIZE << pdk->dk_blkshift;
    403 
    404 	/* fake numbers, 1 cylinder is 1 MB with default sector size */
    405 	dg->dg_nsectors = 32;
    406 	dg->dg_ntracks = 64;
    407 	dg->dg_ncylinders =
    408 	    dg->dg_secperunit / (dg->dg_nsectors * dg->dg_ntracks);
    409 
    410 	dg->dg_physsecsize = pdk->dk_geom.dg_physsecsize;
    411 	dg->dg_alignedsec = pdk->dk_geom.dg_alignedsec;
    412 	lspps = MAX(1u, dg->dg_physsecsize / dg->dg_secsize);
    413 	r = sc->sc_offset % lspps;
    414 	if (r > dg->dg_alignedsec)
    415 		dg->dg_alignedsec += lspps;
    416 	dg->dg_alignedsec -= r;
    417 	dg->dg_alignedsec %= lspps;
    418 
    419 	disk_set_info(sc->sc_dev, dk, NULL);
    420 }
    421 
    422 /*
    423  * dkwedge_add:		[exported function]
    424  *
    425  *	Add a disk wedge based on the provided information.
    426  *
    427  *	The incoming dkw_devname[] is ignored, instead being
    428  *	filled in and returned to the caller.
    429  */
    430 int
    431 dkwedge_add(struct dkwedge_info *dkw)
    432 {
    433 	struct dkwedge_softc *sc, *lsc;
    434 	struct disk *pdk;
    435 	u_int unit;
    436 	int error;
    437 	dev_t pdev;
    438 	device_t dev __diagused;
    439 
    440 	dkw->dkw_parent[sizeof(dkw->dkw_parent) - 1] = '\0';
    441 	pdk = disk_find(dkw->dkw_parent);
    442 	if (pdk == NULL)
    443 		return ENXIO;
    444 
    445 	error = dkwedge_compute_pdev(pdk->dk_name, &pdev, VBLK);
    446 	if (error)
    447 		return error;
    448 
    449 	if (dkw->dkw_offset < 0)
    450 		return EINVAL;
    451 
    452 	/*
    453 	 * Check for an existing wedge at the same disk offset. Allow
    454 	 * updating a wedge if the only change is the size, and the new
    455 	 * size is larger than the old.
    456 	 */
    457 	sc = NULL;
    458 	mutex_enter(&pdk->dk_openlock);
    459 	LIST_FOREACH(lsc, &pdk->dk_wedges, sc_plink) {
    460 		if (lsc->sc_offset != dkw->dkw_offset)
    461 			continue;
    462 		if (strcmp(lsc->sc_wname, dkw->dkw_wname) != 0)
    463 			break;
    464 		if (strcmp(lsc->sc_ptype, dkw->dkw_ptype) != 0)
    465 			break;
    466 		if (dkwedge_size(lsc) > dkw->dkw_size)
    467 			break;
    468 		if (lsc->sc_dev == NULL)
    469 			break;
    470 
    471 		sc = lsc;
    472 		device_acquire(sc->sc_dev);
    473 		dkwedge_size_increase(sc, dkw->dkw_size);
    474 		dk_set_geometry(sc, pdk);
    475 
    476 		break;
    477 	}
    478 	mutex_exit(&pdk->dk_openlock);
    479 
    480 	if (sc != NULL)
    481 		goto announce;
    482 
    483 	sc = malloc(sizeof(*sc), M_DKWEDGE, M_WAITOK|M_ZERO);
    484 	sc->sc_state = DKW_STATE_LARVAL;
    485 	sc->sc_parent = pdk;
    486 	sc->sc_pdev = pdev;
    487 	sc->sc_offset = dkw->dkw_offset;
    488 	dkwedge_size_init(sc, dkw->dkw_size);
    489 
    490 	memcpy(sc->sc_wname, dkw->dkw_wname, sizeof(sc->sc_wname));
    491 	sc->sc_wname[sizeof(sc->sc_wname) - 1] = '\0';
    492 
    493 	memcpy(sc->sc_ptype, dkw->dkw_ptype, sizeof(sc->sc_ptype));
    494 	sc->sc_ptype[sizeof(sc->sc_ptype) - 1] = '\0';
    495 
    496 	bufq_alloc(&sc->sc_bufq, "fcfs", 0);
    497 
    498 	callout_init(&sc->sc_restart_ch, 0);
    499 	callout_setfunc(&sc->sc_restart_ch, dkrestart, sc);
    500 
    501 	mutex_init(&sc->sc_iolock, MUTEX_DEFAULT, IPL_BIO);
    502 
    503 	/*
    504 	 * Wedge will be added; increment the wedge count for the parent.
    505 	 * Only allow this to happen if RAW_PART is the only thing open.
    506 	 */
    507 	mutex_enter(&pdk->dk_openlock);
    508 	if (pdk->dk_openmask & ~(1 << RAW_PART))
    509 		error = EBUSY;
    510 	else {
    511 		/* Check for wedge overlap. */
    512 		LIST_FOREACH(lsc, &pdk->dk_wedges, sc_plink) {
    513 			/* XXX arithmetic overflow */
    514 			uint64_t size = dkwedge_size(sc);
    515 			uint64_t lsize = dkwedge_size(lsc);
    516 			daddr_t lastblk = sc->sc_offset + size - 1;
    517 			daddr_t llastblk = lsc->sc_offset + lsize - 1;
    518 
    519 			if (sc->sc_offset >= lsc->sc_offset &&
    520 			    sc->sc_offset <= llastblk) {
    521 				/* Overlaps the tail of the existing wedge. */
    522 				break;
    523 			}
    524 			if (lastblk >= lsc->sc_offset &&
    525 			    lastblk <= llastblk) {
    526 				/* Overlaps the head of the existing wedge. */
    527 			    	break;
    528 			}
    529 		}
    530 		if (lsc != NULL) {
    531 			if (sc->sc_offset == lsc->sc_offset &&
    532 			    dkwedge_size(sc) == dkwedge_size(lsc) &&
    533 			    strcmp(sc->sc_wname, lsc->sc_wname) == 0)
    534 				error = EEXIST;
    535 			else
    536 				error = EINVAL;
    537 		} else {
    538 			pdk->dk_nwedges++;
    539 			LIST_INSERT_HEAD(&pdk->dk_wedges, sc, sc_plink);
    540 		}
    541 	}
    542 	mutex_exit(&pdk->dk_openlock);
    543 	if (error) {
    544 		mutex_destroy(&sc->sc_iolock);
    545 		bufq_free(sc->sc_bufq);
    546 		dkwedge_size_fini(sc);
    547 		free(sc, M_DKWEDGE);
    548 		return error;
    549 	}
    550 
    551 	/* Fill in our cfdata for the pseudo-device glue. */
    552 	sc->sc_cfdata.cf_name = dk_cd.cd_name;
    553 	sc->sc_cfdata.cf_atname = dk_ca.ca_name;
    554 	/* sc->sc_cfdata.cf_unit set below */
    555 	sc->sc_cfdata.cf_fstate = FSTATE_NOTFOUND; /* use chosen cf_unit */
    556 
    557 	/* Insert the larval wedge into the array. */
    558 	rw_enter(&dkwedges_lock, RW_WRITER);
    559 	for (error = 0;;) {
    560 		struct dkwedge_softc **scpp;
    561 
    562 		/*
    563 		 * Check for a duplicate wname while searching for
    564 		 * a slot.
    565 		 */
    566 		for (scpp = NULL, unit = 0; unit < ndkwedges; unit++) {
    567 			if (dkwedges[unit] == NULL) {
    568 				if (scpp == NULL) {
    569 					scpp = &dkwedges[unit];
    570 					sc->sc_cfdata.cf_unit = unit;
    571 				}
    572 			} else {
    573 				/* XXX Unicode. */
    574 				if (strcmp(dkwedges[unit]->sc_wname,
    575 					sc->sc_wname) == 0) {
    576 					error = EEXIST;
    577 					break;
    578 				}
    579 			}
    580 		}
    581 		if (error)
    582 			break;
    583 		KASSERT(unit == ndkwedges);
    584 		if (scpp == NULL) {
    585 			error = dkwedge_array_expand();
    586 			if (error)
    587 				break;
    588 		} else {
    589 			KASSERT(scpp == &dkwedges[sc->sc_cfdata.cf_unit]);
    590 			*scpp = sc;
    591 			break;
    592 		}
    593 	}
    594 	rw_exit(&dkwedges_lock);
    595 	if (error) {
    596 		mutex_enter(&pdk->dk_openlock);
    597 		pdk->dk_nwedges--;
    598 		LIST_REMOVE(sc, sc_plink);
    599 		mutex_exit(&pdk->dk_openlock);
    600 
    601 		mutex_destroy(&sc->sc_iolock);
    602 		bufq_free(sc->sc_bufq);
    603 		dkwedge_size_fini(sc);
    604 		free(sc, M_DKWEDGE);
    605 		return error;
    606 	}
    607 
    608 	/*
    609 	 * Now that we know the unit #, attach a pseudo-device for
    610 	 * this wedge instance.  This will provide us with the
    611 	 * device_t necessary for glue to other parts of the system.
    612 	 *
    613 	 * This should never fail, unless we're almost totally out of
    614 	 * memory.
    615 	 */
    616 	if ((dev = config_attach_pseudo_acquire(&sc->sc_cfdata, sc)) == NULL) {
    617 		aprint_error("%s%u: unable to attach pseudo-device\n",
    618 		    sc->sc_cfdata.cf_name, sc->sc_cfdata.cf_unit);
    619 
    620 		rw_enter(&dkwedges_lock, RW_WRITER);
    621 		KASSERT(dkwedges[sc->sc_cfdata.cf_unit] == sc);
    622 		dkwedges[sc->sc_cfdata.cf_unit] = NULL;
    623 		rw_exit(&dkwedges_lock);
    624 
    625 		mutex_enter(&pdk->dk_openlock);
    626 		pdk->dk_nwedges--;
    627 		LIST_REMOVE(sc, sc_plink);
    628 		mutex_exit(&pdk->dk_openlock);
    629 
    630 		mutex_destroy(&sc->sc_iolock);
    631 		bufq_free(sc->sc_bufq);
    632 		dkwedge_size_fini(sc);
    633 		free(sc, M_DKWEDGE);
    634 		return ENOMEM;
    635 	}
    636 
    637 	KASSERT(dev == sc->sc_dev);
    638 
    639 announce:
    640 	/* Announce our arrival. */
    641 	aprint_normal(
    642 	    "%s at %s: \"%s\", %"PRIu64" blocks at %"PRId64", type: %s\n",
    643 	    device_xname(sc->sc_dev), pdk->dk_name,
    644 	    sc->sc_wname,	/* XXX Unicode */
    645 	    dkwedge_size(sc), sc->sc_offset,
    646 	    sc->sc_ptype[0] == '\0' ? "<unknown>" : sc->sc_ptype);
    647 
    648 	/* Return the devname to the caller. */
    649 	strlcpy(dkw->dkw_devname, device_xname(sc->sc_dev),
    650 	    sizeof(dkw->dkw_devname));
    651 
    652 	device_release(sc->sc_dev);
    653 	return 0;
    654 }
    655 
    656 /*
    657  * dkwedge_find_acquire:
    658  *
    659  *	Lookup a disk wedge based on the provided information.
    660  *	NOTE: We look up the wedge based on the wedge devname,
    661  *	not wname.
    662  *
    663  *	Return NULL if the wedge is not found, otherwise return
    664  *	the wedge's softc.  Assign the wedge's unit number to unitp
    665  *	if unitp is not NULL.  The wedge's sc_dev is referenced and
    666  *	must be released by device_release or equivalent.
    667  */
    668 static struct dkwedge_softc *
    669 dkwedge_find_acquire(struct dkwedge_info *dkw, u_int *unitp)
    670 {
    671 	struct dkwedge_softc *sc = NULL;
    672 	u_int unit;
    673 
    674 	/* Find our softc. */
    675 	dkw->dkw_devname[sizeof(dkw->dkw_devname) - 1] = '\0';
    676 	rw_enter(&dkwedges_lock, RW_READER);
    677 	for (unit = 0; unit < ndkwedges; unit++) {
    678 		if ((sc = dkwedges[unit]) != NULL &&
    679 		    sc->sc_dev != NULL &&
    680 		    strcmp(device_xname(sc->sc_dev), dkw->dkw_devname) == 0 &&
    681 		    strcmp(sc->sc_parent->dk_name, dkw->dkw_parent) == 0) {
    682 			device_acquire(sc->sc_dev);
    683 			break;
    684 		}
    685 	}
    686 	rw_exit(&dkwedges_lock);
    687 	if (sc == NULL)
    688 		return NULL;
    689 
    690 	if (unitp != NULL)
    691 		*unitp = unit;
    692 
    693 	return sc;
    694 }
    695 
    696 /*
    697  * dkwedge_del:		[exported function]
    698  *
    699  *	Delete a disk wedge based on the provided information.
    700  *	NOTE: We look up the wedge based on the wedge devname,
    701  *	not wname.
    702  */
    703 int
    704 dkwedge_del(struct dkwedge_info *dkw)
    705 {
    706 
    707 	return dkwedge_del1(dkw, 0);
    708 }
    709 
    710 int
    711 dkwedge_del1(struct dkwedge_info *dkw, int flags)
    712 {
    713 	struct dkwedge_softc *sc = NULL;
    714 
    715 	/* Find our softc. */
    716 	if ((sc = dkwedge_find_acquire(dkw, NULL)) == NULL)
    717 		return ESRCH;
    718 
    719 	return config_detach_release(sc->sc_dev, flags);
    720 }
    721 
    722 /*
    723  * dkwedge_detach:
    724  *
    725  *	Autoconfiguration detach function for pseudo-device glue.
    726  */
    727 static int
    728 dkwedge_detach(device_t self, int flags)
    729 {
    730 	struct dkwedge_softc *const sc = device_private(self);
    731 	const u_int unit = device_unit(self);
    732 	int bmaj, cmaj, error;
    733 
    734 	error = disk_begindetach(&sc->sc_dk, /*lastclose*/NULL, self, flags);
    735 	if (error)
    736 		return error;
    737 
    738 	/* Mark the wedge as dying. */
    739 	sc->sc_state = DKW_STATE_DYING;
    740 
    741 	pmf_device_deregister(self);
    742 
    743 	/* Kill any pending restart. */
    744 	mutex_enter(&sc->sc_iolock);
    745 	sc->sc_iostop = true;
    746 	mutex_exit(&sc->sc_iolock);
    747 	callout_halt(&sc->sc_restart_ch, NULL);
    748 
    749 	/* Locate the wedge major numbers. */
    750 	bmaj = bdevsw_lookup_major(&dk_bdevsw);
    751 	cmaj = cdevsw_lookup_major(&dk_cdevsw);
    752 
    753 	/* Nuke the vnodes for any open instances. */
    754 	vdevgone(bmaj, unit, unit, VBLK);
    755 	vdevgone(cmaj, unit, unit, VCHR);
    756 
    757 	/*
    758 	 * At this point, all block device opens have been closed,
    759 	 * synchronously flushing any buffered writes; and all
    760 	 * character device I/O operations have completed
    761 	 * synchronously, and character device opens have been closed.
    762 	 *
    763 	 * So there can be no more opens or queued buffers by now.
    764 	 */
    765 	KASSERT(sc->sc_dk.dk_openmask == 0);
    766 	KASSERT(bufq_peek(sc->sc_bufq) == NULL);
    767 	bufq_drain(sc->sc_bufq);
    768 
    769 	/* Announce our departure. */
    770 	aprint_normal("%s at %s (%s) deleted\n", device_xname(sc->sc_dev),
    771 	    sc->sc_parent->dk_name,
    772 	    sc->sc_wname);	/* XXX Unicode */
    773 
    774 	mutex_enter(&sc->sc_parent->dk_openlock);
    775 	sc->sc_parent->dk_nwedges--;
    776 	LIST_REMOVE(sc, sc_plink);
    777 	mutex_exit(&sc->sc_parent->dk_openlock);
    778 
    779 	/* Delete our buffer queue. */
    780 	bufq_free(sc->sc_bufq);
    781 
    782 	/* Detach from the disk list. */
    783 	disk_detach(&sc->sc_dk);
    784 	disk_destroy(&sc->sc_dk);
    785 
    786 	/* Poof. */
    787 	rw_enter(&dkwedges_lock, RW_WRITER);
    788 	KASSERT(dkwedges[unit] == sc);
    789 	dkwedges[unit] = NULL;
    790 	sc->sc_state = DKW_STATE_DEAD;
    791 	rw_exit(&dkwedges_lock);
    792 
    793 	mutex_destroy(&sc->sc_iolock);
    794 	dkwedge_size_fini(sc);
    795 
    796 	free(sc, M_DKWEDGE);
    797 
    798 	return 0;
    799 }
    800 
    801 /*
    802  * dkwedge_delall:	[exported function]
    803  *
    804  *	Forcibly delete all of the wedges on the specified disk.  Used
    805  *	when a disk is being detached.
    806  */
    807 void
    808 dkwedge_delall(struct disk *pdk)
    809 {
    810 
    811 	dkwedge_delall1(pdk, /*idleonly*/false);
    812 }
    813 
    814 /*
    815  * dkwedge_delidle:	[exported function]
    816  *
    817  *	Delete all of the wedges on the specified disk if idle.  Used
    818  *	by ioctl(DIOCRMWEDGES).
    819  */
    820 void
    821 dkwedge_delidle(struct disk *pdk)
    822 {
    823 
    824 	dkwedge_delall1(pdk, /*idleonly*/true);
    825 }
    826 
    827 static void
    828 dkwedge_delall1(struct disk *pdk, bool idleonly)
    829 {
    830 	struct dkwedge_softc *sc;
    831 	int flags;
    832 
    833 	flags = DETACH_QUIET;
    834 	if (!idleonly)
    835 		flags |= DETACH_FORCE;
    836 
    837 	for (;;) {
    838 		mutex_enter(&pdk->dk_rawlock); /* for sc->sc_dk.dk_openmask */
    839 		mutex_enter(&pdk->dk_openlock);
    840 		LIST_FOREACH(sc, &pdk->dk_wedges, sc_plink) {
    841 			/*
    842 			 * Wedge is not yet created.  This is a race --
    843 			 * it may as well have been added just after we
    844 			 * deleted all the wedges, so pretend it's not
    845 			 * here yet.
    846 			 */
    847 			if (sc->sc_dev == NULL)
    848 				continue;
    849 			if (!idleonly || sc->sc_dk.dk_openmask == 0) {
    850 				device_acquire(sc->sc_dev);
    851 				break;
    852 			}
    853 		}
    854 		if (sc == NULL) {
    855 			KASSERT(idleonly || pdk->dk_nwedges == 0);
    856 			mutex_exit(&pdk->dk_openlock);
    857 			mutex_exit(&pdk->dk_rawlock);
    858 			return;
    859 		}
    860 		mutex_exit(&pdk->dk_openlock);
    861 		mutex_exit(&pdk->dk_rawlock);
    862 		(void)config_detach_release(sc->sc_dev, flags);
    863 	}
    864 }
    865 
    866 /*
    867  * dkwedge_list:	[exported function]
    868  *
    869  *	List all of the wedges on a particular disk.
    870  */
    871 int
    872 dkwedge_list(struct disk *pdk, struct dkwedge_list *dkwl, struct lwp *l)
    873 {
    874 	struct uio uio;
    875 	struct iovec iov;
    876 	struct dkwedge_softc *sc;
    877 	struct dkwedge_info dkw;
    878 	int error = 0;
    879 
    880 	iov.iov_base = dkwl->dkwl_buf;
    881 	iov.iov_len = dkwl->dkwl_bufsize;
    882 
    883 	uio.uio_iov = &iov;
    884 	uio.uio_iovcnt = 1;
    885 	uio.uio_offset = 0;
    886 	uio.uio_resid = dkwl->dkwl_bufsize;
    887 	uio.uio_rw = UIO_READ;
    888 	KASSERT(l == curlwp);
    889 	uio.uio_vmspace = l->l_proc->p_vmspace;
    890 
    891 	dkwl->dkwl_ncopied = 0;
    892 
    893 	mutex_enter(&pdk->dk_openlock);
    894 	LIST_FOREACH(sc, &pdk->dk_wedges, sc_plink) {
    895 		if (uio.uio_resid < sizeof(dkw))
    896 			break;
    897 
    898 		if (sc->sc_dev == NULL)
    899 			continue;
    900 
    901 		strlcpy(dkw.dkw_devname, device_xname(sc->sc_dev),
    902 		    sizeof(dkw.dkw_devname));
    903 		memcpy(dkw.dkw_wname, sc->sc_wname, sizeof(dkw.dkw_wname));
    904 		dkw.dkw_wname[sizeof(dkw.dkw_wname) - 1] = '\0';
    905 		strlcpy(dkw.dkw_parent, sc->sc_parent->dk_name,
    906 		    sizeof(dkw.dkw_parent));
    907 		dkw.dkw_offset = sc->sc_offset;
    908 		dkw.dkw_size = dkwedge_size(sc);
    909 		strlcpy(dkw.dkw_ptype, sc->sc_ptype, sizeof(dkw.dkw_ptype));
    910 
    911 		/*
    912 		 * Acquire a device reference so this wedge doesn't go
    913 		 * away before our next iteration in LIST_FOREACH, and
    914 		 * then release the lock for uiomove.
    915 		 */
    916 		device_acquire(sc->sc_dev);
    917 		mutex_exit(&pdk->dk_openlock);
    918 		error = uiomove(&dkw, sizeof(dkw), &uio);
    919 		mutex_enter(&pdk->dk_openlock);
    920 		device_release(sc->sc_dev);
    921 		if (error)
    922 			break;
    923 
    924 		dkwl->dkwl_ncopied++;
    925 	}
    926 	dkwl->dkwl_nwedges = pdk->dk_nwedges;
    927 	mutex_exit(&pdk->dk_openlock);
    928 
    929 	return error;
    930 }
    931 
    932 static device_t
    933 dkwedge_find_by_wname_acquire(const char *wname)
    934 {
    935 	device_t dv = NULL;
    936 	struct dkwedge_softc *sc;
    937 	int i;
    938 
    939 	rw_enter(&dkwedges_lock, RW_READER);
    940 	for (i = 0; i < ndkwedges; i++) {
    941 		if ((sc = dkwedges[i]) == NULL || sc->sc_dev == NULL)
    942 			continue;
    943 		if (strcmp(sc->sc_wname, wname) == 0) {
    944 			if (dv != NULL) {
    945 				printf(
    946 				    "WARNING: double match for wedge name %s "
    947 				    "(%s, %s)\n", wname, device_xname(dv),
    948 				    device_xname(sc->sc_dev));
    949 				continue;
    950 			}
    951 			device_acquire(sc->sc_dev);
    952 			dv = sc->sc_dev;
    953 		}
    954 	}
    955 	rw_exit(&dkwedges_lock);
    956 	return dv;
    957 }
    958 
    959 static device_t
    960 dkwedge_find_by_parent_acquire(const char *name, size_t *i)
    961 {
    962 
    963 	rw_enter(&dkwedges_lock, RW_READER);
    964 	for (; *i < (size_t)ndkwedges; (*i)++) {
    965 		struct dkwedge_softc *sc;
    966 		if ((sc = dkwedges[*i]) == NULL || sc->sc_dev == NULL)
    967 			continue;
    968 		if (strcmp(sc->sc_parent->dk_name, name) != 0)
    969 			continue;
    970 		device_acquire(sc->sc_dev);
    971 		rw_exit(&dkwedges_lock);
    972 		return sc->sc_dev;
    973 	}
    974 	rw_exit(&dkwedges_lock);
    975 	return NULL;
    976 }
    977 
    978 /* XXX unsafe */
    979 device_t
    980 dkwedge_find_by_wname(const char *wname)
    981 {
    982 	device_t dv;
    983 
    984 	if ((dv = dkwedge_find_by_wname_acquire(wname)) == NULL)
    985 		return NULL;
    986 	device_release(dv);
    987 	return dv;
    988 }
    989 
    990 /* XXX unsafe */
    991 device_t
    992 dkwedge_find_by_parent(const char *name, size_t *i)
    993 {
    994 	device_t dv;
    995 
    996 	if ((dv = dkwedge_find_by_parent_acquire(name, i)) == NULL)
    997 		return NULL;
    998 	device_release(dv);
    999 	return dv;
   1000 }
   1001 
   1002 void
   1003 dkwedge_print_wnames(void)
   1004 {
   1005 	struct dkwedge_softc *sc;
   1006 	int i;
   1007 
   1008 	rw_enter(&dkwedges_lock, RW_READER);
   1009 	for (i = 0; i < ndkwedges; i++) {
   1010 		if ((sc = dkwedges[i]) == NULL || sc->sc_dev == NULL)
   1011 			continue;
   1012 		printf(" wedge:%s", sc->sc_wname);
   1013 	}
   1014 	rw_exit(&dkwedges_lock);
   1015 }
   1016 
   1017 /*
   1018  * We need a dummy object to stuff into the dkwedge discovery method link
   1019  * set to ensure that there is always at least one object in the set.
   1020  */
   1021 static struct dkwedge_discovery_method dummy_discovery_method;
   1022 __link_set_add_bss(dkwedge_methods, dummy_discovery_method);
   1023 
   1024 /*
   1025  * dkwedge_init:
   1026  *
   1027  *	Initialize the disk wedge subsystem.
   1028  */
   1029 void
   1030 dkwedge_init(void)
   1031 {
   1032 	__link_set_decl(dkwedge_methods, struct dkwedge_discovery_method);
   1033 	struct dkwedge_discovery_method * const *ddmp;
   1034 	struct dkwedge_discovery_method *lddm, *ddm;
   1035 
   1036 	rw_init(&dkwedges_lock);
   1037 	rw_init(&dkwedge_discovery_methods_lock);
   1038 
   1039 	if (config_cfdriver_attach(&dk_cd) != 0)
   1040 		panic("dkwedge: unable to attach cfdriver");
   1041 	if (config_cfattach_attach(dk_cd.cd_name, &dk_ca) != 0)
   1042 		panic("dkwedge: unable to attach cfattach");
   1043 
   1044 	rw_enter(&dkwedge_discovery_methods_lock, RW_WRITER);
   1045 
   1046 	LIST_INIT(&dkwedge_discovery_methods);
   1047 
   1048 	__link_set_foreach(ddmp, dkwedge_methods) {
   1049 		ddm = *ddmp;
   1050 		if (ddm == &dummy_discovery_method)
   1051 			continue;
   1052 		if (LIST_EMPTY(&dkwedge_discovery_methods)) {
   1053 			LIST_INSERT_HEAD(&dkwedge_discovery_methods,
   1054 			    ddm, ddm_list);
   1055 			continue;
   1056 		}
   1057 		LIST_FOREACH(lddm, &dkwedge_discovery_methods, ddm_list) {
   1058 			if (ddm->ddm_priority == lddm->ddm_priority) {
   1059 				aprint_error("dk-method-%s: method \"%s\" "
   1060 				    "already exists at priority %d\n",
   1061 				    ddm->ddm_name, lddm->ddm_name,
   1062 				    lddm->ddm_priority);
   1063 				/* Not inserted. */
   1064 				break;
   1065 			}
   1066 			if (ddm->ddm_priority < lddm->ddm_priority) {
   1067 				/* Higher priority; insert before. */
   1068 				LIST_INSERT_BEFORE(lddm, ddm, ddm_list);
   1069 				break;
   1070 			}
   1071 			if (LIST_NEXT(lddm, ddm_list) == NULL) {
   1072 				/* Last one; insert after. */
   1073 				KASSERT(lddm->ddm_priority < ddm->ddm_priority);
   1074 				LIST_INSERT_AFTER(lddm, ddm, ddm_list);
   1075 				break;
   1076 			}
   1077 		}
   1078 	}
   1079 
   1080 	rw_exit(&dkwedge_discovery_methods_lock);
   1081 }
   1082 
   1083 #ifdef DKWEDGE_AUTODISCOVER
   1084 int	dkwedge_autodiscover = 1;
   1085 #else
   1086 int	dkwedge_autodiscover = 0;
   1087 #endif
   1088 
   1089 /*
   1090  * dkwedge_discover:	[exported function]
   1091  *
   1092  *	Discover the wedges on a newly attached disk.
   1093  *	Remove all unused wedges on the disk first.
   1094  */
   1095 void
   1096 dkwedge_discover(struct disk *pdk)
   1097 {
   1098 	struct dkwedge_discovery_method *ddm;
   1099 	struct vnode *vp;
   1100 	int error;
   1101 	dev_t pdev;
   1102 
   1103 	/*
   1104 	 * Require people playing with wedges to enable this explicitly.
   1105 	 */
   1106 	if (dkwedge_autodiscover == 0)
   1107 		return;
   1108 
   1109 	rw_enter(&dkwedge_discovery_methods_lock, RW_READER);
   1110 
   1111 	/*
   1112 	 * Use the character device for scanning, the block device
   1113 	 * is busy if there are already wedges attached.
   1114 	 */
   1115 	error = dkwedge_compute_pdev(pdk->dk_name, &pdev, VCHR);
   1116 	if (error) {
   1117 		aprint_error("%s: unable to compute pdev, error = %d\n",
   1118 		    pdk->dk_name, error);
   1119 		goto out;
   1120 	}
   1121 
   1122 	error = cdevvp(pdev, &vp);
   1123 	if (error) {
   1124 		aprint_error("%s: unable to find vnode for pdev, error = %d\n",
   1125 		    pdk->dk_name, error);
   1126 		goto out;
   1127 	}
   1128 
   1129 	error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
   1130 	if (error) {
   1131 		aprint_error("%s: unable to lock vnode for pdev, error = %d\n",
   1132 		    pdk->dk_name, error);
   1133 		vrele(vp);
   1134 		goto out;
   1135 	}
   1136 
   1137 	error = VOP_OPEN(vp, FREAD | FSILENT, NOCRED);
   1138 	if (error) {
   1139 		if (error != ENXIO)
   1140 			aprint_error("%s: unable to open device, error = %d\n",
   1141 			    pdk->dk_name, error);
   1142 		vput(vp);
   1143 		goto out;
   1144 	}
   1145 	VOP_UNLOCK(vp);
   1146 
   1147 	/*
   1148 	 * Remove unused wedges
   1149 	 */
   1150 	dkwedge_delidle(pdk);
   1151 
   1152 	/*
   1153 	 * For each supported partition map type, look to see if
   1154 	 * this map type exists.  If so, parse it and add the
   1155 	 * corresponding wedges.
   1156 	 */
   1157 	LIST_FOREACH(ddm, &dkwedge_discovery_methods, ddm_list) {
   1158 		error = (*ddm->ddm_discover)(pdk, vp);
   1159 		if (error == 0) {
   1160 			/* Successfully created wedges; we're done. */
   1161 			break;
   1162 		}
   1163 	}
   1164 
   1165 	error = vn_close(vp, FREAD, NOCRED);
   1166 	if (error) {
   1167 		aprint_error("%s: unable to close device, error = %d\n",
   1168 		    pdk->dk_name, error);
   1169 		/* We'll just assume the vnode has been cleaned up. */
   1170 	}
   1171 
   1172 out:
   1173 	rw_exit(&dkwedge_discovery_methods_lock);
   1174 }
   1175 
   1176 /*
   1177  * dkwedge_read:
   1178  *
   1179  *	Read some data from the specified disk, used for
   1180  *	partition discovery.
   1181  */
   1182 int
   1183 dkwedge_read(struct disk *pdk, struct vnode *vp, daddr_t blkno,
   1184     void *tbuf, size_t len)
   1185 {
   1186 	buf_t *bp;
   1187 	int error;
   1188 	bool isopen;
   1189 	dev_t bdev;
   1190 	struct vnode *bdvp;
   1191 
   1192 	/*
   1193 	 * The kernel cannot read from a character device vnode
   1194 	 * as physio() only handles user memory.
   1195 	 *
   1196 	 * If the block device has already been opened by a wedge
   1197 	 * use that vnode and temporarily bump the open counter.
   1198 	 *
   1199 	 * Otherwise try to open the block device.
   1200 	 */
   1201 
   1202 	bdev = devsw_chr2blk(vp->v_rdev);
   1203 
   1204 	mutex_enter(&pdk->dk_rawlock);
   1205 	if (pdk->dk_rawopens != 0) {
   1206 		KASSERT(pdk->dk_rawvp != NULL);
   1207 		isopen = true;
   1208 		++pdk->dk_rawopens;
   1209 		bdvp = pdk->dk_rawvp;
   1210 		error = 0;
   1211 	} else {
   1212 		isopen = false;
   1213 		error = dk_open_parent(bdev, FREAD, &bdvp);
   1214 	}
   1215 	mutex_exit(&pdk->dk_rawlock);
   1216 
   1217 	if (error)
   1218 		return error;
   1219 
   1220 	bp = getiobuf(bdvp, true);
   1221 	bp->b_flags = B_READ;
   1222 	bp->b_cflags = BC_BUSY;
   1223 	bp->b_dev = bdev;
   1224 	bp->b_data = tbuf;
   1225 	bp->b_bufsize = bp->b_bcount = len;
   1226 	bp->b_blkno = blkno;
   1227 	bp->b_cylinder = 0;
   1228 	bp->b_error = 0;
   1229 
   1230 	VOP_STRATEGY(bdvp, bp);
   1231 	error = biowait(bp);
   1232 	putiobuf(bp);
   1233 
   1234 	mutex_enter(&pdk->dk_rawlock);
   1235 	if (isopen) {
   1236 		--pdk->dk_rawopens;
   1237 	} else {
   1238 		dk_close_parent(bdvp, FREAD);
   1239 	}
   1240 	mutex_exit(&pdk->dk_rawlock);
   1241 
   1242 	return error;
   1243 }
   1244 
   1245 /*
   1246  * dkwedge_lookup:
   1247  *
   1248  *	Look up a dkwedge_softc based on the provided dev_t.
   1249  *
   1250  *	Caller must guarantee the wedge is referenced.
   1251  */
   1252 static struct dkwedge_softc *
   1253 dkwedge_lookup(dev_t dev)
   1254 {
   1255 
   1256 	return device_lookup_private(&dk_cd, minor(dev));
   1257 }
   1258 
   1259 static struct dkwedge_softc *
   1260 dkwedge_lookup_acquire(dev_t dev)
   1261 {
   1262 	device_t dv = device_lookup_acquire(&dk_cd, minor(dev));
   1263 
   1264 	if (dv == NULL)
   1265 		return NULL;
   1266 	return device_private(dv);
   1267 }
   1268 
   1269 static int
   1270 dk_open_parent(dev_t dev, int mode, struct vnode **vpp)
   1271 {
   1272 	struct vnode *vp;
   1273 	int error;
   1274 
   1275 	error = bdevvp(dev, &vp);
   1276 	if (error)
   1277 		return error;
   1278 
   1279 	error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
   1280 	if (error) {
   1281 		vrele(vp);
   1282 		return error;
   1283 	}
   1284 	error = VOP_OPEN(vp, mode, NOCRED);
   1285 	if (error) {
   1286 		vput(vp);
   1287 		return error;
   1288 	}
   1289 
   1290 	/* VOP_OPEN() doesn't do this for us. */
   1291 	if (mode & FWRITE) {
   1292 		mutex_enter(vp->v_interlock);
   1293 		vp->v_writecount++;
   1294 		mutex_exit(vp->v_interlock);
   1295 	}
   1296 
   1297 	VOP_UNLOCK(vp);
   1298 
   1299 	*vpp = vp;
   1300 
   1301 	return 0;
   1302 }
   1303 
   1304 static int
   1305 dk_close_parent(struct vnode *vp, int mode)
   1306 {
   1307 	int error;
   1308 
   1309 	error = vn_close(vp, mode, NOCRED);
   1310 	return error;
   1311 }
   1312 
   1313 /*
   1314  * dkopen:		[devsw entry point]
   1315  *
   1316  *	Open a wedge.
   1317  */
   1318 static int
   1319 dkopen(dev_t dev, int flags, int fmt, struct lwp *l)
   1320 {
   1321 	struct dkwedge_softc *sc = dkwedge_lookup(dev);
   1322 	int error = 0;
   1323 
   1324 	if (sc == NULL)
   1325 		return ENXIO;
   1326 	KASSERT(sc->sc_dev != NULL);
   1327 	KASSERT(sc->sc_state == DKW_STATE_RUNNING);
   1328 
   1329 	/*
   1330 	 * We go through a complicated little dance to only open the parent
   1331 	 * vnode once per wedge, no matter how many times the wedge is
   1332 	 * opened.  The reason?  We see one dkopen() per open call, but
   1333 	 * only dkclose() on the last close.
   1334 	 */
   1335 	mutex_enter(&sc->sc_dk.dk_openlock);
   1336 	mutex_enter(&sc->sc_parent->dk_rawlock);
   1337 	if (sc->sc_dk.dk_openmask == 0) {
   1338 		error = dkfirstopen(sc, flags);
   1339 		if (error)
   1340 			goto out;
   1341 	} else if (flags & ~sc->sc_mode & FWRITE) {
   1342 		/*
   1343 		 * The parent is already open, but the previous attempt
   1344 		 * to open it read/write failed and fell back to
   1345 		 * read-only.  In that case, we assume the medium is
   1346 		 * read-only and fail to open the wedge read/write.
   1347 		 */
   1348 		error = EROFS;
   1349 		goto out;
   1350 	}
   1351 	KASSERT(sc->sc_mode != 0);
   1352 	KASSERTMSG(sc->sc_mode & FREAD, "%s: sc_mode=%x",
   1353 	    device_xname(sc->sc_dev), sc->sc_mode);
   1354 	KASSERTMSG((flags & FWRITE) ? (sc->sc_mode & FWRITE) : 1,
   1355 	    "%s: flags=%x sc_mode=%x",
   1356 	    device_xname(sc->sc_dev), flags, sc->sc_mode);
   1357 	if (fmt == S_IFCHR)
   1358 		sc->sc_dk.dk_copenmask |= 1;
   1359 	else
   1360 		sc->sc_dk.dk_bopenmask |= 1;
   1361 	sc->sc_dk.dk_openmask =
   1362 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
   1363 
   1364 out:	mutex_exit(&sc->sc_parent->dk_rawlock);
   1365 	mutex_exit(&sc->sc_dk.dk_openlock);
   1366 	return error;
   1367 }
   1368 
   1369 static int
   1370 dkfirstopen(struct dkwedge_softc *sc, int flags)
   1371 {
   1372 	struct dkwedge_softc *nsc;
   1373 	struct vnode *vp;
   1374 	int mode;
   1375 	int error;
   1376 
   1377 	KASSERT(mutex_owned(&sc->sc_dk.dk_openlock));
   1378 	KASSERT(mutex_owned(&sc->sc_parent->dk_rawlock));
   1379 
   1380 	if (sc->sc_parent->dk_rawopens == 0) {
   1381 		KASSERT(sc->sc_parent->dk_rawvp == NULL);
   1382 		/*
   1383 		 * Try open read-write. If this fails for EROFS
   1384 		 * and wedge is read-only, retry to open read-only.
   1385 		 */
   1386 		mode = FREAD | FWRITE;
   1387 		error = dk_open_parent(sc->sc_pdev, mode, &vp);
   1388 		if (error == EROFS && (flags & FWRITE) == 0) {
   1389 			mode &= ~FWRITE;
   1390 			error = dk_open_parent(sc->sc_pdev, mode, &vp);
   1391 		}
   1392 		if (error)
   1393 			return error;
   1394 		KASSERT(vp != NULL);
   1395 		sc->sc_parent->dk_rawvp = vp;
   1396 	} else {
   1397 		/*
   1398 		 * Retrieve mode from an already opened wedge.
   1399 		 *
   1400 		 * At this point, dk_rawopens is bounded by the number
   1401 		 * of dkwedge devices in the system, which is limited
   1402 		 * by autoconf device numbering to INT_MAX.  Since
   1403 		 * dk_rawopens is unsigned, this can't overflow.
   1404 		 */
   1405 		KASSERT(sc->sc_parent->dk_rawopens < UINT_MAX);
   1406 		KASSERT(sc->sc_parent->dk_rawvp != NULL);
   1407 		mode = 0;
   1408 		mutex_enter(&sc->sc_parent->dk_openlock);
   1409 		LIST_FOREACH(nsc, &sc->sc_parent->dk_wedges, sc_plink) {
   1410 			if (nsc == sc || nsc->sc_dk.dk_openmask == 0)
   1411 				continue;
   1412 			mode = nsc->sc_mode;
   1413 			break;
   1414 		}
   1415 		mutex_exit(&sc->sc_parent->dk_openlock);
   1416 	}
   1417 	sc->sc_mode = mode;
   1418 	sc->sc_parent->dk_rawopens++;
   1419 
   1420 	return 0;
   1421 }
   1422 
   1423 static void
   1424 dklastclose(struct dkwedge_softc *sc)
   1425 {
   1426 
   1427 	KASSERT(mutex_owned(&sc->sc_dk.dk_openlock));
   1428 	KASSERT(mutex_owned(&sc->sc_parent->dk_rawlock));
   1429 	KASSERT(sc->sc_parent->dk_rawopens > 0);
   1430 	KASSERT(sc->sc_parent->dk_rawvp != NULL);
   1431 
   1432 	if (--sc->sc_parent->dk_rawopens == 0) {
   1433 		struct vnode *const vp = sc->sc_parent->dk_rawvp;
   1434 		const int mode = sc->sc_mode;
   1435 
   1436 		sc->sc_parent->dk_rawvp = NULL;
   1437 		sc->sc_mode = 0;
   1438 
   1439 		dk_close_parent(vp, mode);
   1440 	}
   1441 }
   1442 
   1443 /*
   1444  * dkclose:		[devsw entry point]
   1445  *
   1446  *	Close a wedge.
   1447  */
   1448 static int
   1449 dkclose(dev_t dev, int flags, int fmt, struct lwp *l)
   1450 {
   1451 	struct dkwedge_softc *sc = dkwedge_lookup(dev);
   1452 
   1453 	/*
   1454 	 * dkclose can be called even if dkopen didn't succeed, so we
   1455 	 * have to handle the same possibility that the wedge may not
   1456 	 * exist.
   1457 	 */
   1458 	if (sc == NULL)
   1459 		return ENXIO;
   1460 	KASSERT(sc->sc_dev != NULL);
   1461 	KASSERT(sc->sc_state != DKW_STATE_LARVAL);
   1462 	KASSERT(sc->sc_state != DKW_STATE_DEAD);
   1463 
   1464 	mutex_enter(&sc->sc_dk.dk_openlock);
   1465 	mutex_enter(&sc->sc_parent->dk_rawlock);
   1466 
   1467 	KASSERT(sc->sc_dk.dk_openmask != 0);
   1468 
   1469 	if (fmt == S_IFCHR)
   1470 		sc->sc_dk.dk_copenmask &= ~1;
   1471 	else
   1472 		sc->sc_dk.dk_bopenmask &= ~1;
   1473 	sc->sc_dk.dk_openmask =
   1474 	    sc->sc_dk.dk_copenmask | sc->sc_dk.dk_bopenmask;
   1475 
   1476 	if (sc->sc_dk.dk_openmask == 0) {
   1477 		dklastclose(sc);
   1478 	}
   1479 
   1480 	mutex_exit(&sc->sc_parent->dk_rawlock);
   1481 	mutex_exit(&sc->sc_dk.dk_openlock);
   1482 
   1483 	return 0;
   1484 }
   1485 
   1486 /*
   1487  * dkcancel:		[devsw entry point]
   1488  *
   1489  *	Cancel any pending I/O operations waiting on a wedge.
   1490  */
   1491 static int
   1492 dkcancel(dev_t dev, int flags, int fmt, struct lwp *l)
   1493 {
   1494 	struct dkwedge_softc *sc = dkwedge_lookup(dev);
   1495 
   1496 	KASSERT(sc != NULL);
   1497 	KASSERT(sc->sc_dev != NULL);
   1498 	KASSERT(sc->sc_state != DKW_STATE_LARVAL);
   1499 	KASSERT(sc->sc_state != DKW_STATE_DEAD);
   1500 
   1501 	/*
   1502 	 * Disk I/O is expected to complete or fail within a reasonable
   1503 	 * timeframe -- it's storage, not communication.  Further, the
   1504 	 * character and block device interface guarantees that prior
   1505 	 * reads and writes have completed or failed by the time close
   1506 	 * returns -- we are not to cancel them here.  If the parent
   1507 	 * device's hardware is gone, the parent driver can make them
   1508 	 * fail.  Nothing for dk(4) itself to do.
   1509 	 */
   1510 
   1511 	return 0;
   1512 }
   1513 
   1514 /*
   1515  * dkstrategy:		[devsw entry point]
   1516  *
   1517  *	Perform I/O based on the wedge I/O strategy.
   1518  */
   1519 static void
   1520 dkstrategy(struct buf *bp)
   1521 {
   1522 	struct dkwedge_softc *sc = dkwedge_lookup(bp->b_dev);
   1523 	uint64_t p_size, p_offset;
   1524 
   1525 	KASSERT(sc != NULL);
   1526 	KASSERT(sc->sc_dev != NULL);
   1527 	KASSERT(sc->sc_state != DKW_STATE_LARVAL);
   1528 	KASSERT(sc->sc_state != DKW_STATE_DEAD);
   1529 	KASSERT(sc->sc_parent->dk_rawvp != NULL);
   1530 
   1531 	/* If it's an empty transfer, wake up the top half now. */
   1532 	if (bp->b_bcount == 0)
   1533 		goto done;
   1534 
   1535 	p_offset = sc->sc_offset << sc->sc_parent->dk_blkshift;
   1536 	p_size = dkwedge_size(sc) << sc->sc_parent->dk_blkshift;
   1537 
   1538 	/* Make sure it's in-range. */
   1539 	if (bounds_check_with_mediasize(bp, DEV_BSIZE, p_size) <= 0)
   1540 		goto done;
   1541 
   1542 	/* Translate it to the parent's raw LBA. */
   1543 	bp->b_rawblkno = bp->b_blkno + p_offset;
   1544 
   1545 	/* Place it in the queue and start I/O on the unit. */
   1546 	mutex_enter(&sc->sc_iolock);
   1547 	disk_wait(&sc->sc_dk);
   1548 	bufq_put(sc->sc_bufq, bp);
   1549 	mutex_exit(&sc->sc_iolock);
   1550 
   1551 	dkstart(sc);
   1552 	return;
   1553 
   1554 done:
   1555 	bp->b_resid = bp->b_bcount;
   1556 	biodone(bp);
   1557 }
   1558 
   1559 /*
   1560  * dkstart:
   1561  *
   1562  *	Start I/O that has been enqueued on the wedge.
   1563  */
   1564 static void
   1565 dkstart(struct dkwedge_softc *sc)
   1566 {
   1567 	struct vnode *vp;
   1568 	struct buf *bp, *nbp;
   1569 
   1570 	mutex_enter(&sc->sc_iolock);
   1571 
   1572 	/* Do as much work as has been enqueued. */
   1573 	while ((bp = bufq_peek(sc->sc_bufq)) != NULL) {
   1574 		if (sc->sc_iostop) {
   1575 			(void) bufq_get(sc->sc_bufq);
   1576 			mutex_exit(&sc->sc_iolock);
   1577 			bp->b_error = ENXIO;
   1578 			bp->b_resid = bp->b_bcount;
   1579 			biodone(bp);
   1580 			mutex_enter(&sc->sc_iolock);
   1581 			continue;
   1582 		}
   1583 
   1584 		/* fetch an I/O buf with sc_iolock dropped */
   1585 		mutex_exit(&sc->sc_iolock);
   1586 		nbp = getiobuf(sc->sc_parent->dk_rawvp, false);
   1587 		mutex_enter(&sc->sc_iolock);
   1588 		if (nbp == NULL) {
   1589 			/*
   1590 			 * No resources to run this request; leave the
   1591 			 * buffer queued up, and schedule a timer to
   1592 			 * restart the queue in 1/2 a second.
   1593 			 */
   1594 			if (!sc->sc_iostop)
   1595 				callout_schedule(&sc->sc_restart_ch, hz/2);
   1596 			break;
   1597 		}
   1598 
   1599 		/*
   1600 		 * fetch buf, this can fail if another thread
   1601 		 * has already processed the queue, it can also
   1602 		 * return a completely different buf.
   1603 		 */
   1604 		bp = bufq_get(sc->sc_bufq);
   1605 		if (bp == NULL) {
   1606 			mutex_exit(&sc->sc_iolock);
   1607 			putiobuf(nbp);
   1608 			mutex_enter(&sc->sc_iolock);
   1609 			continue;
   1610 		}
   1611 
   1612 		/* Instrumentation. */
   1613 		disk_busy(&sc->sc_dk);
   1614 
   1615 		/* release lock for VOP_STRATEGY */
   1616 		mutex_exit(&sc->sc_iolock);
   1617 
   1618 		nbp->b_data = bp->b_data;
   1619 		nbp->b_flags = bp->b_flags;
   1620 		nbp->b_oflags = bp->b_oflags;
   1621 		nbp->b_cflags = bp->b_cflags;
   1622 		nbp->b_iodone = dkiodone;
   1623 		nbp->b_proc = bp->b_proc;
   1624 		nbp->b_blkno = bp->b_rawblkno;
   1625 		nbp->b_dev = sc->sc_parent->dk_rawvp->v_rdev;
   1626 		nbp->b_bcount = bp->b_bcount;
   1627 		nbp->b_private = bp;
   1628 		BIO_COPYPRIO(nbp, bp);
   1629 
   1630 		vp = nbp->b_vp;
   1631 		if ((nbp->b_flags & B_READ) == 0) {
   1632 			mutex_enter(vp->v_interlock);
   1633 			vp->v_numoutput++;
   1634 			mutex_exit(vp->v_interlock);
   1635 		}
   1636 		VOP_STRATEGY(vp, nbp);
   1637 
   1638 		mutex_enter(&sc->sc_iolock);
   1639 	}
   1640 
   1641 	mutex_exit(&sc->sc_iolock);
   1642 }
   1643 
   1644 /*
   1645  * dkiodone:
   1646  *
   1647  *	I/O to a wedge has completed; alert the top half.
   1648  */
   1649 static void
   1650 dkiodone(struct buf *bp)
   1651 {
   1652 	struct buf *obp = bp->b_private;
   1653 	struct dkwedge_softc *sc = dkwedge_lookup(obp->b_dev);
   1654 
   1655 	KASSERT(sc != NULL);
   1656 	KASSERT(sc->sc_dev != NULL);
   1657 
   1658 	if (bp->b_error != 0)
   1659 		obp->b_error = bp->b_error;
   1660 	obp->b_resid = bp->b_resid;
   1661 	putiobuf(bp);
   1662 
   1663 	mutex_enter(&sc->sc_iolock);
   1664 	disk_unbusy(&sc->sc_dk, obp->b_bcount - obp->b_resid,
   1665 	    obp->b_flags & B_READ);
   1666 	mutex_exit(&sc->sc_iolock);
   1667 
   1668 	biodone(obp);
   1669 
   1670 	/* Kick the queue in case there is more work we can do. */
   1671 	dkstart(sc);
   1672 }
   1673 
   1674 /*
   1675  * dkrestart:
   1676  *
   1677  *	Restart the work queue after it was stalled due to
   1678  *	a resource shortage.  Invoked via a callout.
   1679  */
   1680 static void
   1681 dkrestart(void *v)
   1682 {
   1683 	struct dkwedge_softc *sc = v;
   1684 
   1685 	dkstart(sc);
   1686 }
   1687 
   1688 /*
   1689  * dkminphys:
   1690  *
   1691  *	Call parent's minphys function.
   1692  */
   1693 static void
   1694 dkminphys(struct buf *bp)
   1695 {
   1696 	struct dkwedge_softc *sc = dkwedge_lookup(bp->b_dev);
   1697 	dev_t dev;
   1698 
   1699 	KASSERT(sc != NULL);
   1700 	KASSERT(sc->sc_dev != NULL);
   1701 
   1702 	dev = bp->b_dev;
   1703 	bp->b_dev = sc->sc_pdev;
   1704 	if (sc->sc_parent->dk_driver && sc->sc_parent->dk_driver->d_minphys)
   1705 		(*sc->sc_parent->dk_driver->d_minphys)(bp);
   1706 	else
   1707 		minphys(bp);
   1708 	bp->b_dev = dev;
   1709 }
   1710 
   1711 /*
   1712  * dkread:		[devsw entry point]
   1713  *
   1714  *	Read from a wedge.
   1715  */
   1716 static int
   1717 dkread(dev_t dev, struct uio *uio, int flags)
   1718 {
   1719 	struct dkwedge_softc *sc __diagused = dkwedge_lookup(dev);
   1720 
   1721 	KASSERT(sc != NULL);
   1722 	KASSERT(sc->sc_dev != NULL);
   1723 	KASSERT(sc->sc_state != DKW_STATE_LARVAL);
   1724 	KASSERT(sc->sc_state != DKW_STATE_DEAD);
   1725 
   1726 	return physio(dkstrategy, NULL, dev, B_READ, dkminphys, uio);
   1727 }
   1728 
   1729 /*
   1730  * dkwrite:		[devsw entry point]
   1731  *
   1732  *	Write to a wedge.
   1733  */
   1734 static int
   1735 dkwrite(dev_t dev, struct uio *uio, int flags)
   1736 {
   1737 	struct dkwedge_softc *sc __diagused = dkwedge_lookup(dev);
   1738 
   1739 	KASSERT(sc != NULL);
   1740 	KASSERT(sc->sc_dev != NULL);
   1741 	KASSERT(sc->sc_state != DKW_STATE_LARVAL);
   1742 	KASSERT(sc->sc_state != DKW_STATE_DEAD);
   1743 
   1744 	return physio(dkstrategy, NULL, dev, B_WRITE, dkminphys, uio);
   1745 }
   1746 
   1747 /*
   1748  * dkioctl:		[devsw entry point]
   1749  *
   1750  *	Perform an ioctl request on a wedge.
   1751  */
   1752 static int
   1753 dkioctl(dev_t dev, u_long cmd, void *data, int flag, struct lwp *l)
   1754 {
   1755 	struct dkwedge_softc *sc = dkwedge_lookup(dev);
   1756 	int error = 0;
   1757 
   1758 	KASSERT(sc != NULL);
   1759 	KASSERT(sc->sc_dev != NULL);
   1760 	KASSERT(sc->sc_state != DKW_STATE_LARVAL);
   1761 	KASSERT(sc->sc_state != DKW_STATE_DEAD);
   1762 	KASSERT(sc->sc_parent->dk_rawvp != NULL);
   1763 
   1764 	/*
   1765 	 * We pass NODEV instead of our device to indicate we don't
   1766 	 * want to handle disklabel ioctls
   1767 	 */
   1768 	error = disk_ioctl(&sc->sc_dk, NODEV, cmd, data, flag, l);
   1769 	if (error != EPASSTHROUGH)
   1770 		return error;
   1771 
   1772 	error = 0;
   1773 
   1774 	switch (cmd) {
   1775 	case DIOCGSTRATEGY:
   1776 	case DIOCGCACHE:
   1777 	case DIOCCACHESYNC:
   1778 		error = VOP_IOCTL(sc->sc_parent->dk_rawvp, cmd, data, flag,
   1779 		    l != NULL ? l->l_cred : NOCRED);
   1780 		break;
   1781 	case DIOCGWEDGEINFO: {
   1782 		struct dkwedge_info *dkw = data;
   1783 
   1784 		strlcpy(dkw->dkw_devname, device_xname(sc->sc_dev),
   1785 		    sizeof(dkw->dkw_devname));
   1786 	    	memcpy(dkw->dkw_wname, sc->sc_wname, sizeof(dkw->dkw_wname));
   1787 		dkw->dkw_wname[sizeof(dkw->dkw_wname) - 1] = '\0';
   1788 		strlcpy(dkw->dkw_parent, sc->sc_parent->dk_name,
   1789 		    sizeof(dkw->dkw_parent));
   1790 		dkw->dkw_offset = sc->sc_offset;
   1791 		dkw->dkw_size = dkwedge_size(sc);
   1792 		strlcpy(dkw->dkw_ptype, sc->sc_ptype, sizeof(dkw->dkw_ptype));
   1793 
   1794 		break;
   1795 	}
   1796 	case DIOCGSECTORALIGN: {
   1797 		struct disk_sectoralign *dsa = data;
   1798 		uint32_t r;
   1799 
   1800 		error = VOP_IOCTL(sc->sc_parent->dk_rawvp, cmd, dsa, flag,
   1801 		    l != NULL ? l->l_cred : NOCRED);
   1802 		if (error)
   1803 			break;
   1804 
   1805 		r = sc->sc_offset % dsa->dsa_alignment;
   1806 		if (r < dsa->dsa_firstaligned)
   1807 			dsa->dsa_firstaligned = dsa->dsa_firstaligned - r;
   1808 		else
   1809 			dsa->dsa_firstaligned = (dsa->dsa_firstaligned +
   1810 			    dsa->dsa_alignment) - r;
   1811 		dsa->dsa_firstaligned %= dsa->dsa_alignment;
   1812 		break;
   1813 	}
   1814 	default:
   1815 		error = ENOTTY;
   1816 	}
   1817 
   1818 	return error;
   1819 }
   1820 
   1821 /*
   1822  * dkdiscard:		[devsw entry point]
   1823  *
   1824  *	Perform a discard-range request on a wedge.
   1825  */
   1826 static int
   1827 dkdiscard(dev_t dev, off_t pos, off_t len)
   1828 {
   1829 	struct dkwedge_softc *sc = dkwedge_lookup(dev);
   1830 	uint64_t size = dkwedge_size(sc);
   1831 	unsigned shift;
   1832 	off_t offset, maxlen;
   1833 	int error;
   1834 
   1835 	KASSERT(sc != NULL);
   1836 	KASSERT(sc->sc_dev != NULL);
   1837 	KASSERT(sc->sc_state != DKW_STATE_LARVAL);
   1838 	KASSERT(sc->sc_state != DKW_STATE_DEAD);
   1839 	KASSERT(sc->sc_parent->dk_rawvp != NULL);
   1840 
   1841 	/* XXX check bounds on size/offset up front */
   1842 	shift = (sc->sc_parent->dk_blkshift + DEV_BSHIFT);
   1843 	KASSERT(__type_fit(off_t, size));
   1844 	KASSERT(__type_fit(off_t, sc->sc_offset));
   1845 	KASSERT(0 <= sc->sc_offset);
   1846 	KASSERT(size <= (__type_max(off_t) >> shift));
   1847 	KASSERT(sc->sc_offset <= ((__type_max(off_t) >> shift) - size));
   1848 	offset = ((off_t)sc->sc_offset << shift);
   1849 	maxlen = ((off_t)size << shift);
   1850 
   1851 	if (len > maxlen)
   1852 		return EINVAL;
   1853 	if (pos > (maxlen - len))
   1854 		return EINVAL;
   1855 
   1856 	pos += offset;
   1857 
   1858 	vn_lock(sc->sc_parent->dk_rawvp, LK_EXCLUSIVE | LK_RETRY);
   1859 	error = VOP_FDISCARD(sc->sc_parent->dk_rawvp, pos, len);
   1860 	VOP_UNLOCK(sc->sc_parent->dk_rawvp);
   1861 
   1862 	return error;
   1863 }
   1864 
   1865 /*
   1866  * dksize:		[devsw entry point]
   1867  *
   1868  *	Query the size of a wedge for the purpose of performing a dump
   1869  *	or for swapping to.
   1870  */
   1871 static int
   1872 dksize(dev_t dev)
   1873 {
   1874 	/*
   1875 	 * Don't bother taking a reference because this is only used
   1876 	 * either (a) while the device is open (for swap), or (b) while
   1877 	 * any multiprocessing is quiescent (for crash dumps).
   1878 	 */
   1879 	struct dkwedge_softc *sc = dkwedge_lookup(dev);
   1880 	uint64_t p_size;
   1881 	int rv = -1;
   1882 
   1883 	if (sc == NULL)
   1884 		return -1;
   1885 	if (sc->sc_state != DKW_STATE_RUNNING)
   1886 		return -1;
   1887 
   1888 	/* Our content type is static, no need to open the device. */
   1889 
   1890 	p_size = dkwedge_size(sc) << sc->sc_parent->dk_blkshift;
   1891 	if (strcmp(sc->sc_ptype, DKW_PTYPE_SWAP) == 0) {
   1892 		/* Saturate if we are larger than INT_MAX. */
   1893 		if (p_size > INT_MAX)
   1894 			rv = INT_MAX;
   1895 		else
   1896 			rv = (int)p_size;
   1897 	}
   1898 
   1899 	return rv;
   1900 }
   1901 
   1902 /*
   1903  * dkdump:		[devsw entry point]
   1904  *
   1905  *	Perform a crash dump to a wedge.
   1906  */
   1907 static int
   1908 dkdump(dev_t dev, daddr_t blkno, void *va, size_t size)
   1909 {
   1910 	/*
   1911 	 * Don't bother taking a reference because this is only used
   1912 	 * while any multiprocessing is quiescent.
   1913 	 */
   1914 	struct dkwedge_softc *sc = dkwedge_lookup(dev);
   1915 	const struct bdevsw *bdev;
   1916 	uint64_t p_size, p_offset;
   1917 
   1918 	if (sc == NULL)
   1919 		return ENXIO;
   1920 	if (sc->sc_state != DKW_STATE_RUNNING)
   1921 		return ENXIO;
   1922 
   1923 	/* Our content type is static, no need to open the device. */
   1924 
   1925 	if (strcmp(sc->sc_ptype, DKW_PTYPE_SWAP) != 0 &&
   1926 	    strcmp(sc->sc_ptype, DKW_PTYPE_RAID) != 0 &&
   1927 	    strcmp(sc->sc_ptype, DKW_PTYPE_CGD) != 0)
   1928 		return ENXIO;
   1929 	if (size % DEV_BSIZE != 0)
   1930 		return EINVAL;
   1931 
   1932 	p_offset = sc->sc_offset << sc->sc_parent->dk_blkshift;
   1933 	p_size = dkwedge_size(sc) << sc->sc_parent->dk_blkshift;
   1934 
   1935 	if (blkno < 0 || blkno + size/DEV_BSIZE > p_size) {
   1936 		printf("%s: blkno (%" PRIu64 ") + size / DEV_BSIZE (%zu) > "
   1937 		    "p_size (%" PRIu64 ")\n", __func__, blkno,
   1938 		    size/DEV_BSIZE, p_size);
   1939 		return EINVAL;
   1940 	}
   1941 
   1942 	bdev = bdevsw_lookup(sc->sc_pdev);
   1943 	return (*bdev->d_dump)(sc->sc_pdev, blkno + p_offset, va, size);
   1944 }
   1945 
   1946 /*
   1947  * config glue
   1948  */
   1949 
   1950 /*
   1951  * dkwedge_find_partition
   1952  *
   1953  *	Find wedge corresponding to the specified parent name
   1954  *	and offset/length.
   1955  */
   1956 static device_t
   1957 dkwedge_find_partition_acquire(device_t parent, daddr_t startblk,
   1958     uint64_t nblks)
   1959 {
   1960 	struct dkwedge_softc *sc;
   1961 	int i;
   1962 	device_t wedge = NULL;
   1963 
   1964 	rw_enter(&dkwedges_lock, RW_READER);
   1965 	for (i = 0; i < ndkwedges; i++) {
   1966 		if ((sc = dkwedges[i]) == NULL || sc->sc_dev == NULL)
   1967 			continue;
   1968 		if (strcmp(sc->sc_parent->dk_name, device_xname(parent)) == 0 &&
   1969 		    sc->sc_offset == startblk &&
   1970 		    dkwedge_size(sc) == nblks) {
   1971 			if (wedge) {
   1972 				printf("WARNING: double match for boot wedge "
   1973 				    "(%s, %s)\n",
   1974 				    device_xname(wedge),
   1975 				    device_xname(sc->sc_dev));
   1976 				continue;
   1977 			}
   1978 			wedge = sc->sc_dev;
   1979 			device_acquire(wedge);
   1980 		}
   1981 	}
   1982 	rw_exit(&dkwedges_lock);
   1983 
   1984 	return wedge;
   1985 }
   1986 
   1987 /* XXX unsafe */
   1988 device_t
   1989 dkwedge_find_partition(device_t parent, daddr_t startblk,
   1990     uint64_t nblks)
   1991 {
   1992 	device_t dv;
   1993 
   1994 	if ((dv = dkwedge_find_partition_acquire(parent, startblk, nblks))
   1995 	    == NULL)
   1996 		return NULL;
   1997 	device_release(dv);
   1998 	return dv;
   1999 }
   2000 
   2001 const char *
   2002 dkwedge_get_parent_name(dev_t dev)
   2003 {
   2004 	/* XXX: perhaps do this in lookup? */
   2005 	int bmaj = bdevsw_lookup_major(&dk_bdevsw);
   2006 	int cmaj = cdevsw_lookup_major(&dk_cdevsw);
   2007 
   2008 	if (major(dev) != bmaj && major(dev) != cmaj)
   2009 		return NULL;
   2010 
   2011 	struct dkwedge_softc *const sc = dkwedge_lookup_acquire(dev);
   2012 	if (sc == NULL)
   2013 		return NULL;
   2014 	const char *const name = sc->sc_parent->dk_name;
   2015 	device_release(sc->sc_dev);
   2016 	return name;
   2017 }
   2018