keyserv(1): drop useless comparison.

[freebsd-src.git] / sys / geom / geom_dev.c

/*-
 * Copyright (c) 2002 Poul-Henning Kamp
 * Copyright (c) 2002 Networks Associates Technology, Inc.
 * All rights reserved.
 *
 * This software was developed for the FreeBSD Project by Poul-Henning Kamp
 * and NAI Labs, the Security Research Division of Network Associates, Inc.
 * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
 * DARPA CHATS research program.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The names of the authors may not be used to endorse or promote
 *    products derived from this software without specific prior written
 *    permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/ctype.h>
#include <sys/bio.h>
#include <sys/bus.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/disk.h>
#include <sys/fcntl.h>
#include <sys/limits.h>
#include <sys/sysctl.h>
#include <geom/geom.h>
#include <geom/geom_int.h>
#include <machine/stdarg.h>

struct g_dev_softc {
        struct mtx       sc_mtx;
        struct cdev     *sc_dev;
        struct cdev     *sc_alias;
        int              sc_open;
        int              sc_active;
};

static d_open_t         g_dev_open;
static d_close_t        g_dev_close;
static d_strategy_t     g_dev_strategy;
static d_ioctl_t        g_dev_ioctl;

static struct cdevsw g_dev_cdevsw = {
        .d_version =    D_VERSION,
        .d_open =       g_dev_open,
        .d_close =      g_dev_close,
        .d_read =       physread,
        .d_write =      physwrite,
        .d_ioctl =      g_dev_ioctl,
        .d_strategy =   g_dev_strategy,
        .d_name =       "g_dev",
        .d_flags =      D_DISK | D_TRACKCLOSE,
};

static g_init_t g_dev_init;
static g_fini_t g_dev_fini;
static g_taste_t g_dev_taste;
static g_orphan_t g_dev_orphan;
static g_attrchanged_t g_dev_attrchanged;

static struct g_class g_dev_class       = {
        .name = "DEV",
        .version = G_VERSION,
        .init = g_dev_init,
        .fini = g_dev_fini,
        .taste = g_dev_taste,
        .orphan = g_dev_orphan,
        .attrchanged = g_dev_attrchanged
};

/*
 * We target 262144 (8 x 32768) sectors by default as this significantly
 * increases the throughput on commonly used SSD's with a marginal
 * increase in non-interruptible request latency.
 */
static uint64_t g_dev_del_max_sectors = 262144;
SYSCTL_DECL(_kern_geom);
SYSCTL_NODE(_kern_geom, OID_AUTO, dev, CTLFLAG_RW, 0, "GEOM_DEV stuff");
SYSCTL_QUAD(_kern_geom_dev, OID_AUTO, delete_max_sectors, CTLFLAG_RW,
    &g_dev_del_max_sectors, 0, "Maximum number of sectors in a single "
    "delete request sent to the provider. Larger requests are chunked "
    "so they can be interrupted. (0 = disable chunking)");

static char *dumpdev = NULL;
static void
g_dev_init(struct g_class *mp)
{

        dumpdev = kern_getenv("dumpdev");
}

static void
g_dev_fini(struct g_class *mp)
{

        freeenv(dumpdev);
        dumpdev = NULL;
}

static int
g_dev_setdumpdev(struct cdev *dev, struct thread *td)
{
        struct g_kerneldump kd;
        struct g_consumer *cp;
        int error, len;

        if (dev == NULL)
                return (set_dumper(NULL, NULL, td));

        cp = dev->si_drv2;
        len = sizeof(kd);
        kd.offset = 0;
        kd.length = OFF_MAX;
        error = g_io_getattr("GEOM::kerneldump", cp, &len, &kd);
        if (error == 0) {
                error = set_dumper(&kd.di, devtoname(dev), td);
                if (error == 0)
                        dev->si_flags |= SI_DUMPDEV;
        }
        return (error);
}

static int
init_dumpdev(struct cdev *dev)
{
        struct g_consumer *cp;
        const char *devprefix = "/dev/", *devname;
        int error;
        size_t len;

        if (dumpdev == NULL)
                return (0);

        len = strlen(devprefix);
        devname = devtoname(dev);
        if (strcmp(devname, dumpdev) != 0 &&
           (strncmp(dumpdev, devprefix, len) != 0 ||
            strcmp(devname, dumpdev + len) != 0))
                return (0);

        cp = (struct g_consumer *)dev->si_drv2;
        error = g_access(cp, 1, 0, 0);
        if (error != 0)
                return (error);

        error = g_dev_setdumpdev(dev, curthread);
        if (error == 0) {
                freeenv(dumpdev);
                dumpdev = NULL;
        }

        (void)g_access(cp, -1, 0, 0);

        return (error);
}

static void
g_dev_destroy(void *arg, int flags __unused)
{
        struct g_consumer *cp;
        struct g_geom *gp;
        struct g_dev_softc *sc;
        char buf[SPECNAMELEN + 6];

        g_topology_assert();
        cp = arg;
        gp = cp->geom;
        sc = cp->private;
        g_trace(G_T_TOPOLOGY, "g_dev_destroy(%p(%s))", cp, gp->name);
        snprintf(buf, sizeof(buf), "cdev=%s", gp->name);
        devctl_notify_f("GEOM", "DEV", "DESTROY", buf, M_WAITOK);
        if (cp->acr > 0 || cp->acw > 0 || cp->ace > 0)
                g_access(cp, -cp->acr, -cp->acw, -cp->ace);
        g_detach(cp);
        g_destroy_consumer(cp);
        g_destroy_geom(gp);
        mtx_destroy(&sc->sc_mtx);
        g_free(sc);
}

void
g_dev_print(void)
{
        struct g_geom *gp;
        char const *p = "";

        LIST_FOREACH(gp, &g_dev_class.geom, geom) {
                printf("%s%s", p, gp->name);
                p = " ";
        }
        printf("\n");
}

static void
g_dev_set_physpath(struct g_consumer *cp)
{
        struct g_dev_softc *sc;
        char *physpath;
        int error, physpath_len;

        if (g_access(cp, 1, 0, 0) != 0)
                return;

        sc = cp->private;
        physpath_len = MAXPATHLEN;
        physpath = g_malloc(physpath_len, M_WAITOK|M_ZERO);
        error = g_io_getattr("GEOM::physpath", cp, &physpath_len, physpath);
        g_access(cp, -1, 0, 0);
        if (error == 0 && strlen(physpath) != 0) {
                struct cdev *dev, *old_alias_dev;
                struct cdev **alias_devp;

                dev = sc->sc_dev;
                old_alias_dev = sc->sc_alias;
                alias_devp = (struct cdev **)&sc->sc_alias;
                make_dev_physpath_alias(MAKEDEV_WAITOK, alias_devp, dev,
                    old_alias_dev, physpath);
        } else if (sc->sc_alias) {
                destroy_dev((struct cdev *)sc->sc_alias);
                sc->sc_alias = NULL;
        }
        g_free(physpath);
}

static void
g_dev_set_media(struct g_consumer *cp)
{
        struct g_dev_softc *sc;
        struct cdev *dev;
        char buf[SPECNAMELEN + 6];

        sc = cp->private;
        dev = sc->sc_dev;
        snprintf(buf, sizeof(buf), "cdev=%s", dev->si_name);
        devctl_notify_f("DEVFS", "CDEV", "MEDIACHANGE", buf, M_WAITOK);
        devctl_notify_f("GEOM", "DEV", "MEDIACHANGE", buf, M_WAITOK);
        dev = sc->sc_alias;
        if (dev != NULL) {
                snprintf(buf, sizeof(buf), "cdev=%s", dev->si_name);
                devctl_notify_f("DEVFS", "CDEV", "MEDIACHANGE", buf, M_WAITOK);
                devctl_notify_f("GEOM", "DEV", "MEDIACHANGE", buf, M_WAITOK);
        }
}

static void
g_dev_attrchanged(struct g_consumer *cp, const char *attr)
{

        if (strcmp(attr, "GEOM::media") == 0) {
                g_dev_set_media(cp);
                return;
        }

        if (strcmp(attr, "GEOM::physpath") == 0) {
                g_dev_set_physpath(cp);
                return;
        }
}

struct g_provider *
g_dev_getprovider(struct cdev *dev)
{
        struct g_consumer *cp;

        g_topology_assert();
        if (dev == NULL)
                return (NULL);
        if (dev->si_devsw != &g_dev_cdevsw)
                return (NULL);
        cp = dev->si_drv2;
        return (cp->provider);
}

static struct g_geom *
g_dev_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
{
        struct g_geom *gp;
        struct g_consumer *cp;
        struct g_dev_softc *sc;
        int error;
        struct cdev *dev;
        char buf[SPECNAMELEN + 6];

        g_trace(G_T_TOPOLOGY, "dev_taste(%s,%s)", mp->name, pp->name);
        g_topology_assert();
        gp = g_new_geomf(mp, "%s", pp->name);
        sc = g_malloc(sizeof(*sc), M_WAITOK | M_ZERO);
        mtx_init(&sc->sc_mtx, "g_dev", NULL, MTX_DEF);
        cp = g_new_consumer(gp);
        cp->private = sc;
        cp->flags |= G_CF_DIRECT_SEND | G_CF_DIRECT_RECEIVE;
        error = g_attach(cp, pp);
        KASSERT(error == 0,
            ("g_dev_taste(%s) failed to g_attach, err=%d", pp->name, error));
        error = make_dev_p(MAKEDEV_CHECKNAME | MAKEDEV_WAITOK, &dev,
            &g_dev_cdevsw, NULL, UID_ROOT, GID_OPERATOR, 0640, "%s", gp->name);
        if (error != 0) {
                printf("%s: make_dev_p() failed (gp->name=%s, error=%d)\n",
                    __func__, gp->name, error);
                g_detach(cp);
                g_destroy_consumer(cp);
                g_destroy_geom(gp);
                mtx_destroy(&sc->sc_mtx);
                g_free(sc);
                return (NULL);
        }
        dev->si_flags |= SI_UNMAPPED;
        sc->sc_dev = dev;

        dev->si_iosize_max = MAXPHYS;
        dev->si_drv2 = cp;
        error = init_dumpdev(dev);
        if (error != 0)
                printf("%s: init_dumpdev() failed (gp->name=%s, error=%d)\n",
                    __func__, gp->name, error);

        g_dev_attrchanged(cp, "GEOM::physpath");
        snprintf(buf, sizeof(buf), "cdev=%s", gp->name);
        devctl_notify_f("GEOM", "DEV", "CREATE", buf, M_WAITOK);

        return (gp);
}

static int
g_dev_open(struct cdev *dev, int flags, int fmt, struct thread *td)
{
        struct g_consumer *cp;
        struct g_dev_softc *sc;
        int error, r, w, e;

        cp = dev->si_drv2;
        if (cp == NULL)
                return (ENXIO);         /* g_dev_taste() not done yet */
        g_trace(G_T_ACCESS, "g_dev_open(%s, %d, %d, %p)",
            cp->geom->name, flags, fmt, td);

        r = flags & FREAD ? 1 : 0;
        w = flags & FWRITE ? 1 : 0;
#ifdef notyet
        e = flags & O_EXCL ? 1 : 0;
#else
        e = 0;
#endif

        /*
         * This happens on attempt to open a device node with O_EXEC.
         */
        if (r + w + e == 0)
                return (EINVAL);

        if (w) {
                /*
                 * When running in very secure mode, do not allow
                 * opens for writing of any disks.
                 */
                error = securelevel_ge(td->td_ucred, 2);
                if (error)
                        return (error);
        }
        g_topology_lock();
        error = g_access(cp, r, w, e);
        g_topology_unlock();
        if (error == 0) {
                sc = cp->private;
                mtx_lock(&sc->sc_mtx);
                if (sc->sc_open == 0 && sc->sc_active != 0)
                        wakeup(&sc->sc_active);
                sc->sc_open += r + w + e;
                mtx_unlock(&sc->sc_mtx);
        }
        return (error);
}

static int
g_dev_close(struct cdev *dev, int flags, int fmt, struct thread *td)
{
        struct g_consumer *cp;
        struct g_dev_softc *sc;
        int error, r, w, e;

        cp = dev->si_drv2;
        if (cp == NULL)
                return (ENXIO);
        g_trace(G_T_ACCESS, "g_dev_close(%s, %d, %d, %p)",
            cp->geom->name, flags, fmt, td);

        r = flags & FREAD ? -1 : 0;
        w = flags & FWRITE ? -1 : 0;
#ifdef notyet
        e = flags & O_EXCL ? -1 : 0;
#else
        e = 0;
#endif

        /*
         * The vgonel(9) - caused by eg. forced unmount of devfs - calls
         * VOP_CLOSE(9) on devfs vnode without any FREAD or FWRITE flags,
         * which would result in zero deltas, which in turn would cause
         * panic in g_access(9).
         *
         * Note that we cannot zero the counters (ie. do "r = cp->acr"
         * etc) instead, because the consumer might be opened in another
         * devfs instance.
         */
        if (r + w + e == 0)
                return (EINVAL);

        sc = cp->private;
        mtx_lock(&sc->sc_mtx);
        sc->sc_open += r + w + e;
        while (sc->sc_open == 0 && sc->sc_active != 0)
                msleep(&sc->sc_active, &sc->sc_mtx, 0, "PRIBIO", 0);
        mtx_unlock(&sc->sc_mtx);
        g_topology_lock();
        error = g_access(cp, r, w, e);
        g_topology_unlock();
        return (error);
}

/*
 * XXX: Until we have unmessed the ioctl situation, there is a race against
 * XXX: a concurrent orphanization.  We cannot close it by holding topology
 * XXX: since that would prevent us from doing our job, and stalling events
 * XXX: will break (actually: stall) the BSD disklabel hacks.
 */
static int
g_dev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
{
        struct g_consumer *cp;
        struct g_provider *pp;
        off_t offset, length, chunk;
        int i, error;

        cp = dev->si_drv2;
        pp = cp->provider;

        error = 0;
        KASSERT(cp->acr || cp->acw,
            ("Consumer with zero access count in g_dev_ioctl"));

        i = IOCPARM_LEN(cmd);
        switch (cmd) {
        case DIOCGSECTORSIZE:
                *(u_int *)data = cp->provider->sectorsize;
                if (*(u_int *)data == 0)
                        error = ENOENT;
                break;
        case DIOCGMEDIASIZE:
                *(off_t *)data = cp->provider->mediasize;
                if (*(off_t *)data == 0)
                        error = ENOENT;
                break;
        case DIOCGFWSECTORS:
                error = g_io_getattr("GEOM::fwsectors", cp, &i, data);
                if (error == 0 && *(u_int *)data == 0)
                        error = ENOENT;
                break;
        case DIOCGFWHEADS:
                error = g_io_getattr("GEOM::fwheads", cp, &i, data);
                if (error == 0 && *(u_int *)data == 0)
                        error = ENOENT;
                break;
        case DIOCGFRONTSTUFF:
                error = g_io_getattr("GEOM::frontstuff", cp, &i, data);
                break;
        case DIOCSKERNELDUMP:
                if (*(u_int *)data == 0)
                        error = g_dev_setdumpdev(NULL, td);
                else
                        error = g_dev_setdumpdev(dev, td);
                break;
        case DIOCGFLUSH:
                error = g_io_flush(cp);
                break;
        case DIOCGDELETE:
                offset = ((off_t *)data)[0];
                length = ((off_t *)data)[1];
                if ((offset % cp->provider->sectorsize) != 0 ||
                    (length % cp->provider->sectorsize) != 0 || length <= 0) {
                        printf("%s: offset=%jd length=%jd\n", __func__, offset,
                            length);
                        error = EINVAL;
                        break;
                }
                while (length > 0) {
                        chunk = length;
                        if (g_dev_del_max_sectors != 0 && chunk >
                            g_dev_del_max_sectors * cp->provider->sectorsize) {
                                chunk = g_dev_del_max_sectors *
                                    cp->provider->sectorsize;
                        }
                        error = g_delete_data(cp, offset, chunk);
                        length -= chunk;
                        offset += chunk;
                        if (error)
                                break;
                        /*
                         * Since the request size can be large, the service
                         * time can be is likewise.  We make this ioctl
                         * interruptible by checking for signals for each bio.
                         */
                        if (SIGPENDING(td))
                                break;
                }
                break;
        case DIOCGIDENT:
                error = g_io_getattr("GEOM::ident", cp, &i, data);
                break;
        case DIOCGPROVIDERNAME:
                if (pp == NULL)
                        return (ENOENT);
                strlcpy(data, pp->name, i);
                break;
        case DIOCGSTRIPESIZE:
                *(off_t *)data = cp->provider->stripesize;
                break;
        case DIOCGSTRIPEOFFSET:
                *(off_t *)data = cp->provider->stripeoffset;
                break;
        case DIOCGPHYSPATH:
                error = g_io_getattr("GEOM::physpath", cp, &i, data);
                if (error == 0 && *(char *)data == '\0')
                        error = ENOENT;
                break;
        case DIOCGATTR: {
                struct diocgattr_arg *arg = (struct diocgattr_arg *)data;

                if (arg->len > sizeof(arg->value)) {
                        error = EINVAL;
                        break;
                }
                error = g_io_getattr(arg->name, cp, &arg->len, &arg->value);
                break;
        }
        case DIOCZONECMD: {
                struct disk_zone_args *zone_args =(struct disk_zone_args *)data;
                struct disk_zone_rep_entry *new_entries, *old_entries;
                struct disk_zone_report *rep;
                size_t alloc_size;

                old_entries = NULL;
                new_entries = NULL;
                rep = NULL;
                alloc_size = 0;

                if (zone_args->zone_cmd == DISK_ZONE_REPORT_ZONES) {

                        rep = &zone_args->zone_params.report;
                        alloc_size = rep->entries_allocated *
                            sizeof(struct disk_zone_rep_entry);
                        if (alloc_size != 0)
                                new_entries = g_malloc(alloc_size,
                                    M_WAITOK| M_ZERO);
                        old_entries = rep->entries;
                        rep->entries = new_entries;
                }
                error = g_io_zonecmd(zone_args, cp);
                if ((zone_args->zone_cmd == DISK_ZONE_REPORT_ZONES)
                 && (alloc_size != 0)
                 && (error == 0)) {
                        error = copyout(new_entries, old_entries, alloc_size);
                }
                if ((old_entries != NULL)
                 && (rep != NULL))
                        rep->entries = old_entries;

                if (new_entries != NULL)
                        g_free(new_entries);
                break;
        }
        default:
                if (cp->provider->geom->ioctl != NULL) {
                        error = cp->provider->geom->ioctl(cp->provider, cmd, data, fflag, td);
                } else {
                        error = ENOIOCTL;
                }
        }

        return (error);
}

static void
g_dev_done(struct bio *bp2)
{
        struct g_consumer *cp;
        struct g_dev_softc *sc;
        struct bio *bp;
        int destroy;

        cp = bp2->bio_from;
        sc = cp->private;
        bp = bp2->bio_parent;
        bp->bio_error = bp2->bio_error;
        bp->bio_completed = bp2->bio_completed;
        bp->bio_resid = bp->bio_length - bp2->bio_completed;
        if (bp2->bio_cmd == BIO_ZONE)
                bcopy(&bp2->bio_zone, &bp->bio_zone, sizeof(bp->bio_zone));

        if (bp2->bio_error != 0) {
                g_trace(G_T_BIO, "g_dev_done(%p) had error %d",
                    bp2, bp2->bio_error);
                bp->bio_flags |= BIO_ERROR;
        } else {
                g_trace(G_T_BIO, "g_dev_done(%p/%p) resid %ld completed %jd",
                    bp2, bp, bp2->bio_resid, (intmax_t)bp2->bio_completed);
        }
        g_destroy_bio(bp2);
        destroy = 0;
        mtx_lock(&sc->sc_mtx);
        if ((--sc->sc_active) == 0) {
                if (sc->sc_open == 0)
                        wakeup(&sc->sc_active);
                if (sc->sc_dev == NULL)
                        destroy = 1;
        }
        mtx_unlock(&sc->sc_mtx);
        if (destroy)
                g_post_event(g_dev_destroy, cp, M_NOWAIT, NULL);
        biodone(bp);
}

static void
g_dev_strategy(struct bio *bp)
{
        struct g_consumer *cp;
        struct bio *bp2;
        struct cdev *dev;
        struct g_dev_softc *sc;

        KASSERT(bp->bio_cmd == BIO_READ ||
                bp->bio_cmd == BIO_WRITE ||
                bp->bio_cmd == BIO_DELETE ||
                bp->bio_cmd == BIO_FLUSH ||
                bp->bio_cmd == BIO_ZONE,
                ("Wrong bio_cmd bio=%p cmd=%d", bp, bp->bio_cmd));
        dev = bp->bio_dev;
        cp = dev->si_drv2;
        sc = cp->private;
        KASSERT(cp->acr || cp->acw,
            ("Consumer with zero access count in g_dev_strategy"));
#ifdef INVARIANTS
        if ((bp->bio_offset % cp->provider->sectorsize) != 0 ||
            (bp->bio_bcount % cp->provider->sectorsize) != 0) {
                bp->bio_resid = bp->bio_bcount;
                biofinish(bp, NULL, EINVAL);
                return;
        }
#endif
        mtx_lock(&sc->sc_mtx);
        KASSERT(sc->sc_open > 0, ("Closed device in g_dev_strategy"));
        sc->sc_active++;
        mtx_unlock(&sc->sc_mtx);

        for (;;) {
                /*
                 * XXX: This is not an ideal solution, but I believe it to
                 * XXX: deadlock safely, all things considered.
                 */
                bp2 = g_clone_bio(bp);
                if (bp2 != NULL)
                        break;
                pause("gdstrat", hz / 10);
        }
        KASSERT(bp2 != NULL, ("XXX: ENOMEM in a bad place"));
        bp2->bio_done = g_dev_done;
        g_trace(G_T_BIO,
            "g_dev_strategy(%p/%p) offset %jd length %jd data %p cmd %d",
            bp, bp2, (intmax_t)bp->bio_offset, (intmax_t)bp2->bio_length,
            bp2->bio_data, bp2->bio_cmd);
        g_io_request(bp2, cp);
        KASSERT(cp->acr || cp->acw,
            ("g_dev_strategy raced with g_dev_close and lost"));

}

/*
 * g_dev_callback()
 *
 * Called by devfs when asynchronous device destruction is completed.
 * - Mark that we have no attached device any more.
 * - If there are no outstanding requests, schedule geom destruction.
 *   Otherwise destruction will be scheduled later by g_dev_done().
 */

static void
g_dev_callback(void *arg)
{
        struct g_consumer *cp;
        struct g_dev_softc *sc;
        int destroy;

        cp = arg;
        sc = cp->private;
        g_trace(G_T_TOPOLOGY, "g_dev_callback(%p(%s))", cp, cp->geom->name);

        mtx_lock(&sc->sc_mtx);
        sc->sc_dev = NULL;
        sc->sc_alias = NULL;
        destroy = (sc->sc_active == 0);
        mtx_unlock(&sc->sc_mtx);
        if (destroy)
                g_post_event(g_dev_destroy, cp, M_WAITOK, NULL);
}

/*
 * g_dev_orphan()
 *
 * Called from below when the provider orphaned us.
 * - Clear any dump settings.
 * - Request asynchronous device destruction to prevent any more requests
 *   from coming in.  The provider is already marked with an error, so
 *   anything which comes in the interim will be returned immediately.
 */

static void
g_dev_orphan(struct g_consumer *cp)
{
        struct cdev *dev;
        struct g_dev_softc *sc;

        g_topology_assert();
        sc = cp->private;
        dev = sc->sc_dev;
        g_trace(G_T_TOPOLOGY, "g_dev_orphan(%p(%s))", cp, cp->geom->name);

        /* Reset any dump-area set on this device */
        if (dev->si_flags & SI_DUMPDEV)
                (void)set_dumper(NULL, NULL, curthread);

        /* Destroy the struct cdev *so we get no more requests */
        destroy_dev_sched_cb(dev, g_dev_callback, cp);
}

DECLARE_GEOM_CLASS(g_dev_class, g_dev);