NetBSD/sys/dev/dm/dm_dev.c

/*        $NetBSD: dm_dev.c,v 1.19 2021/08/21 22:23:33 andvar Exp $      */

/*
 * Copyright (c) 2008 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Adam Hamsik.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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>
__KERNEL_RCSID(0, "$NetBSD: dm_dev.c,v 1.19 2021/08/21 22:23:33 andvar Exp $");

#include <sys/types.h>
#include <sys/param.h>
#include <sys/disk.h>
#include <sys/disklabel.h>
#include <sys/ioctl.h>
#include <sys/ioccom.h>
#include <sys/kmem.h>

#include "netbsd-dm.h"
#include "dm.h"

static dm_dev_t *dm_dev_lookup_name(const char *);
static dm_dev_t *dm_dev_lookup_uuid(const char *);
static dm_dev_t *dm_dev_lookup_minor(int);

static struct dm_dev_head dm_dev_list = TAILQ_HEAD_INITIALIZER(dm_dev_list);

static kmutex_t dm_dev_mutex;

/* dm_dev_mutex must be holdby caller before using disable_dev. */
static void
disable_dev(dm_dev_t *dmv)
{

	TAILQ_REMOVE(&dm_dev_list, dmv, next_devlist);
	mutex_enter(&dmv->dev_mtx);
	mutex_exit(&dm_dev_mutex);
	while (dmv->ref_cnt != 0)
		cv_wait(&dmv->dev_cv, &dmv->dev_mtx);
	mutex_exit(&dmv->dev_mtx);
}

/*
 * Generic function used to lookup dm_dev_t. Calling with dm_dev_name
 * and dm_dev_uuid NULL is allowed.
 */
dm_dev_t *
dm_dev_lookup(const char *dm_dev_name, const char *dm_dev_uuid,
    int dm_dev_minor)
{
	dm_dev_t *dmv;

	mutex_enter(&dm_dev_mutex);
	/* KASSERT(dm_dev_name != NULL && dm_dev_uuid != NULL && dm_dev_minor
	 * > 0); */
	if (dm_dev_minor > 0)
		if ((dmv = dm_dev_lookup_minor(dm_dev_minor)) != NULL) {
			dm_dev_busy(dmv);
			mutex_exit(&dm_dev_mutex);
			return dmv;
		}
	if (dm_dev_name != NULL)
		if ((dmv = dm_dev_lookup_name(dm_dev_name)) != NULL) {
			dm_dev_busy(dmv);
			mutex_exit(&dm_dev_mutex);
			return dmv;
		}
	if (dm_dev_uuid != NULL)
		if ((dmv = dm_dev_lookup_uuid(dm_dev_uuid)) != NULL) {
			dm_dev_busy(dmv);
			mutex_exit(&dm_dev_mutex);
			return dmv;
		}
	mutex_exit(&dm_dev_mutex);

	return NULL;
}

/*
 * Lookup device with its minor number.
 */
static dm_dev_t *
dm_dev_lookup_minor(int dm_dev_minor)
{
	dm_dev_t *dmv;

	TAILQ_FOREACH(dmv, &dm_dev_list, next_devlist)
		if (dm_dev_minor == dmv->minor)
			return dmv;

	return NULL;
}

/*
 * Lookup device with its device name.
 */
static dm_dev_t *
dm_dev_lookup_name(const char *dm_dev_name)
{
	dm_dev_t *dmv;
	size_t dlen;
	size_t slen;

	slen = strlen(dm_dev_name);

	if (slen == 0)
		return NULL;

	TAILQ_FOREACH(dmv, &dm_dev_list, next_devlist) {
		dlen = strlen(dmv->name);

		if (slen != dlen)
			continue;

		if (strncmp(dm_dev_name, dmv->name, slen) == 0)
			return dmv;
	}

	return NULL;
}

/*
 * Lookup device with its device uuid. Used mostly by LVM2tools.
 */
static dm_dev_t *
dm_dev_lookup_uuid(const char *dm_dev_uuid)
{
	dm_dev_t *dmv;
	size_t len;

	len = 0;
	len = strlen(dm_dev_uuid);

	if (len == 0)
		return NULL;

	TAILQ_FOREACH(dmv, &dm_dev_list, next_devlist) {
		if (strlen(dmv->uuid) != len)
			continue;

		if (strncmp(dm_dev_uuid, dmv->uuid, strlen(dmv->uuid)) == 0)
			return dmv;
	}

	return NULL;
}

/*
 * Insert new device to the global list of devices.
 */
int
dm_dev_insert(dm_dev_t *dev)
{
	dm_dev_t *dmv;
	int r;

	dmv = NULL;
	r = 0;

	KASSERT(dev != NULL);
	mutex_enter(&dm_dev_mutex);
	if (((dmv = dm_dev_lookup_uuid(dev->uuid)) == NULL) &&
	    ((dmv = dm_dev_lookup_name(dev->name)) == NULL) &&
	    ((dmv = dm_dev_lookup_minor(dev->minor)) == NULL)) {
		TAILQ_INSERT_TAIL(&dm_dev_list, dev, next_devlist);
	} else
		r = EEXIST;
	mutex_exit(&dm_dev_mutex);

	return r;
}

#ifdef notyet
/*
 * Lookup device with its minor number.
 */
int
dm_dev_test_minor(int dm_dev_minor)
{
	dm_dev_t *dmv;

	mutex_enter(&dm_dev_mutex);
	TAILQ_FOREACH(dmv, &dm_dev_list, next_devlist) {
		if (dm_dev_minor == dmv->minor) {
			mutex_exit(&dm_dev_mutex);
			return 1;
		}
	}
	mutex_exit(&dm_dev_mutex);

	return 0;
}
#endif

/*
 * dm_dev_lookup_devt look for selected device_t. We keep this routine
 * outside of dm_dev_lookup because it is a temporally solution.
 *
 * TODO: This is a hack autoconf should be more flexible.
 */
dm_dev_t *
dm_dev_detach(device_t devt)
{
	dm_dev_t *dmv;

	mutex_enter(&dm_dev_mutex);
	TAILQ_FOREACH(dmv, &dm_dev_list, next_devlist) {
		if (devt == dmv->devt) {
			disable_dev(dmv);
			return dmv;
		}
	}
	mutex_exit(&dm_dev_mutex);

	return NULL;
}

/*
 * Remove device selected with dm_dev from global list of devices.
 */
dm_dev_t *
dm_dev_rem(const char *dm_dev_name, const char *dm_dev_uuid,
    int dm_dev_minor)
{
	dm_dev_t *dmv;

	mutex_enter(&dm_dev_mutex);
	if (dm_dev_minor > 0)
		if ((dmv = dm_dev_lookup_minor(dm_dev_minor)) != NULL) {
			disable_dev(dmv);
			return dmv;
		}
	if (dm_dev_name != NULL)
		if ((dmv = dm_dev_lookup_name(dm_dev_name)) != NULL) {
			disable_dev(dmv);
			return dmv;
		}
	if (dm_dev_uuid != NULL)
		if ((dmv = dm_dev_lookup_name(dm_dev_uuid)) != NULL) {
			disable_dev(dmv);
			return dmv;
		}
	mutex_exit(&dm_dev_mutex);

	return NULL;
}

/*
 * Destroy all devices created in device-mapper. Remove all tables
 * free all allocated memory.
 */
int
dm_dev_destroy(void)
{
	dm_dev_t *dmv;

	mutex_enter(&dm_dev_mutex);
	while (TAILQ_FIRST(&dm_dev_list) != NULL) {
		dmv = TAILQ_FIRST(&dm_dev_list);

		TAILQ_REMOVE(&dm_dev_list, TAILQ_FIRST(&dm_dev_list),
		    next_devlist);

		mutex_enter(&dmv->dev_mtx);

		while (dmv->ref_cnt != 0)
			cv_wait(&dmv->dev_cv, &dmv->dev_mtx);

		/* Destroy active table first.  */
		dm_table_destroy(&dmv->table_head, DM_TABLE_ACTIVE);

		/* Destroy inactive table if exits, too. */
		dm_table_destroy(&dmv->table_head, DM_TABLE_INACTIVE);

		dm_table_head_destroy(&dmv->table_head);

		mutex_exit(&dmv->dev_mtx);
		mutex_destroy(&dmv->dev_mtx);
		cv_destroy(&dmv->dev_cv);

		kmem_free(dmv, sizeof(dm_dev_t));
	}
	mutex_exit(&dm_dev_mutex);

	mutex_destroy(&dm_dev_mutex);
	return 0;
}

/*
 * Allocate new device entry.
 */
dm_dev_t *
dm_dev_alloc(void)
{
	dm_dev_t *dmv;

	dmv = kmem_zalloc(sizeof(dm_dev_t), KM_SLEEP);
	dmv->diskp = kmem_zalloc(sizeof(struct disk), KM_SLEEP);
	return dmv;
}

/*
 * Freed device entry.
 */
int
dm_dev_free(dm_dev_t *dmv)
{

	KASSERT(dmv != NULL);

	mutex_destroy(&dmv->dev_mtx);
	mutex_destroy(&dmv->diskp_mtx);
	cv_destroy(&dmv->dev_cv);

	if (dmv->diskp != NULL)
		kmem_free(dmv->diskp, sizeof(struct disk));

	kmem_free(dmv, sizeof(dm_dev_t));

	return 0;
}

void
dm_dev_busy(dm_dev_t *dmv)
{

	mutex_enter(&dmv->dev_mtx);
	dmv->ref_cnt++;
	mutex_exit(&dmv->dev_mtx);
}

void
dm_dev_unbusy(dm_dev_t *dmv)
{

	KASSERT(dmv->ref_cnt != 0);

	mutex_enter(&dmv->dev_mtx);
	if (--dmv->ref_cnt == 0)
		cv_broadcast(&dmv->dev_cv);
	mutex_exit(&dmv->dev_mtx);
}

/*
 * Return prop_array of dm_targer_list dictionaries.
 */
prop_array_t
dm_dev_prop_list(void)
{
	dm_dev_t *dmv;
	prop_array_t dev_array;
	prop_dictionary_t dev_dict;

	dev_array = prop_array_create();

	mutex_enter(&dm_dev_mutex);

	TAILQ_FOREACH(dmv, &dm_dev_list, next_devlist) {
		dev_dict = prop_dictionary_create();

		prop_dictionary_set_string(dev_dict, DM_DEV_NAME, dmv->name);
		prop_dictionary_set_uint32(dev_dict, DM_DEV_DEV, dmv->minor);

		prop_array_add(dev_array, dev_dict);
		prop_object_release(dev_dict);
	}

	mutex_exit(&dm_dev_mutex);
	return dev_array;
}

/*
 * Initialize global device mutex.
 */
int
dm_dev_init(void)
{

	TAILQ_INIT(&dm_dev_list);	/* initialize global dev list */
	mutex_init(&dm_dev_mutex, MUTEX_DEFAULT, IPL_NONE);
	return 0;
}