drivers/md/dm-table.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2001 Sistina Software (UK) Limited.
 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
 *
 * This file is released under the GPL.
 */

#include "dm-core.h"
#include "dm-rq.h"

#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/blkdev.h>
#include <linux/blk-integrity.h>
#include <linux/namei.h>
#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/delay.h>
#include <linux/atomic.h>
#include <linux/blk-mq.h>
#include <linux/mount.h>
#include <linux/dax.h>

#define DM_MSG_PREFIX "table"

#define NODE_SIZE L1_CACHE_BYTES
#define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
#define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)

/*
 * Similar to ceiling(log_size(n))
 */
static unsigned int int_log(unsigned int n, unsigned int base)
{
	int result = 0;

	while (n > 1) {
		n = dm_div_up(n, base);
		result++;
	}

	return result;
}

/*
 * Calculate the index of the child node of the n'th node k'th key.
 */
static inline unsigned int get_child(unsigned int n, unsigned int k)
{
	return (n * CHILDREN_PER_NODE) + k;
}

/*
 * Return the n'th node of level l from table t.
 */
static inline sector_t *get_node(struct dm_table *t,
				 unsigned int l, unsigned int n)
{
	return t->index[l] + (n * KEYS_PER_NODE);
}

/*
 * Return the highest key that you could lookup from the n'th
 * node on level l of the btree.
 */
static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
{
	for (; l < t->depth - 1; l++)
		n = get_child(n, CHILDREN_PER_NODE - 1);

	if (n >= t->counts[l])
		return (sector_t) -1;

	return get_node(t, l, n)[KEYS_PER_NODE - 1];
}

/*
 * Fills in a level of the btree based on the highs of the level
 * below it.
 */
static int setup_btree_index(unsigned int l, struct dm_table *t)
{
	unsigned int n, k;
	sector_t *node;

	for (n = 0U; n < t->counts[l]; n++) {
		node = get_node(t, l, n);

		for (k = 0U; k < KEYS_PER_NODE; k++)
			node[k] = high(t, l + 1, get_child(n, k));
	}

	return 0;
}

/*
 * highs, and targets are managed as dynamic arrays during a
 * table load.
 */
static int alloc_targets(struct dm_table *t, unsigned int num)
{
	sector_t *n_highs;
	struct dm_target *n_targets;

	/*
	 * Allocate both the target array and offset array at once.
	 */
	n_highs = kvcalloc(num, sizeof(struct dm_target) + sizeof(sector_t),
			   GFP_KERNEL);
	if (!n_highs)
		return -ENOMEM;

	n_targets = (struct dm_target *) (n_highs + num);

	memset(n_highs, -1, sizeof(*n_highs) * num);
	kvfree(t->highs);

	t->num_allocated = num;
	t->highs = n_highs;
	t->targets = n_targets;

	return 0;
}

int dm_table_create(struct dm_table **result, blk_mode_t mode,
		    unsigned int num_targets, struct mapped_device *md)
{
	struct dm_table *t;

	if (num_targets > DM_MAX_TARGETS)
		return -EOVERFLOW;

	t = kzalloc(sizeof(*t), GFP_KERNEL);

	if (!t)
		return -ENOMEM;

	INIT_LIST_HEAD(&t->devices);
	init_rwsem(&t->devices_lock);

	if (!num_targets)
		num_targets = KEYS_PER_NODE;

	num_targets = dm_round_up(num_targets, KEYS_PER_NODE);

	if (!num_targets) {
		kfree(t);
		return -EOVERFLOW;
	}

	if (alloc_targets(t, num_targets)) {
		kfree(t);
		return -ENOMEM;
	}

	t->type = DM_TYPE_NONE;
	t->mode = mode;
	t->md = md;
	t->flush_bypasses_map = true;
	*result = t;
	return 0;
}

static void free_devices(struct list_head *devices, struct mapped_device *md)
{
	struct list_head *tmp, *next;

	list_for_each_safe(tmp, next, devices) {
		struct dm_dev_internal *dd =
		    list_entry(tmp, struct dm_dev_internal, list);
		DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s",
		       dm_device_name(md), dd->dm_dev->name);
		dm_put_table_device(md, dd->dm_dev);
		kfree(dd);
	}
}

static void dm_table_destroy_crypto_profile(struct dm_table *t);

void dm_table_destroy(struct dm_table *t)
{
	if (!t)
		return;

	/* free the indexes */
	if (t->depth >= 2)
		kvfree(t->index[t->depth - 2]);

	/* free the targets */
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (ti->type->dtr)
			ti->type->dtr(ti);

		dm_put_target_type(ti->type);
	}

	kvfree(t->highs);

	/* free the device list */
	free_devices(&t->devices, t->md);

	dm_free_md_mempools(t->mempools);

	dm_table_destroy_crypto_profile(t);

	kfree(t);
}

/*
 * See if we've already got a device in the list.
 */
static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
{
	struct dm_dev_internal *dd;

	list_for_each_entry(dd, l, list)
		if (dd->dm_dev->bdev->bd_dev == dev)
			return dd;

	return NULL;
}

/*
 * If possible, this checks an area of a destination device is invalid.
 */
static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
				  sector_t start, sector_t len, void *data)
{
	struct queue_limits *limits = data;
	struct block_device *bdev = dev->bdev;
	sector_t dev_size = bdev_nr_sectors(bdev);
	unsigned short logical_block_size_sectors =
		limits->logical_block_size >> SECTOR_SHIFT;

	if (!dev_size)
		return 0;

	if ((start >= dev_size) || (start + len > dev_size)) {
		DMERR("%s: %pg too small for target: start=%llu, len=%llu, dev_size=%llu",
		      dm_device_name(ti->table->md), bdev,
		      (unsigned long long)start,
		      (unsigned long long)len,
		      (unsigned long long)dev_size);
		return 1;
	}

	/*
	 * If the target is mapped to zoned block device(s), check
	 * that the zones are not partially mapped.
	 */
	if (bdev_is_zoned(bdev)) {
		unsigned int zone_sectors = bdev_zone_sectors(bdev);

		if (start & (zone_sectors - 1)) {
			DMERR("%s: start=%llu not aligned to h/w zone size %u of %pg",
			      dm_device_name(ti->table->md),
			      (unsigned long long)start,
			      zone_sectors, bdev);
			return 1;
		}

		/*
		 * Note: The last zone of a zoned block device may be smaller
		 * than other zones. So for a target mapping the end of a
		 * zoned block device with such a zone, len would not be zone
		 * aligned. We do not allow such last smaller zone to be part
		 * of the mapping here to ensure that mappings with multiple
		 * devices do not end up with a smaller zone in the middle of
		 * the sector range.
		 */
		if (len & (zone_sectors - 1)) {
			DMERR("%s: len=%llu not aligned to h/w zone size %u of %pg",
			      dm_device_name(ti->table->md),
			      (unsigned long long)len,
			      zone_sectors, bdev);
			return 1;
		}
	}

	if (logical_block_size_sectors <= 1)
		return 0;

	if (start & (logical_block_size_sectors - 1)) {
		DMERR("%s: start=%llu not aligned to h/w logical block size %u of %pg",
		      dm_device_name(ti->table->md),
		      (unsigned long long)start,
		      limits->logical_block_size, bdev);
		return 1;
	}

	if (len & (logical_block_size_sectors - 1)) {
		DMERR("%s: len=%llu not aligned to h/w logical block size %u of %pg",
		      dm_device_name(ti->table->md),
		      (unsigned long long)len,
		      limits->logical_block_size, bdev);
		return 1;
	}

	return 0;
}

/*
 * This upgrades the mode on an already open dm_dev, being
 * careful to leave things as they were if we fail to reopen the
 * device and not to touch the existing bdev field in case
 * it is accessed concurrently.
 */
static int upgrade_mode(struct dm_dev_internal *dd, blk_mode_t new_mode,
			struct mapped_device *md)
{
	int r;
	struct dm_dev *old_dev, *new_dev;

	old_dev = dd->dm_dev;

	r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
				dd->dm_dev->mode | new_mode, &new_dev);
	if (r)
		return r;

	dd->dm_dev = new_dev;
	dm_put_table_device(md, old_dev);

	return 0;
}

/*
 * Note: the __ref annotation is because this function can call the __init
 * marked early_lookup_bdev when called during early boot code from dm-init.c.
 */
int __ref dm_devt_from_path(const char *path, dev_t *dev_p)
{
	int r;
	dev_t dev;
	unsigned int major, minor;
	char dummy;

	if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) {
		/* Extract the major/minor numbers */
		dev = MKDEV(major, minor);
		if (MAJOR(dev) != major || MINOR(dev) != minor)
			return -EOVERFLOW;
	} else {
		r = lookup_bdev(path, &dev);
#ifndef MODULE
		if (r && system_state < SYSTEM_RUNNING)
			r = early_lookup_bdev(path, &dev);
#endif
		if (r)
			return r;
	}
	*dev_p = dev;
	return 0;
}
EXPORT_SYMBOL(dm_devt_from_path);

/*
 * Add a device to the list, or just increment the usage count if
 * it's already present.
 */
int dm_get_device(struct dm_target *ti, const char *path, blk_mode_t mode,
		  struct dm_dev **result)
{
	int r;
	dev_t dev;
	struct dm_dev_internal *dd;
	struct dm_table *t = ti->table;

	BUG_ON(!t);

	r = dm_devt_from_path(path, &dev);
	if (r)
		return r;

	if (dev == disk_devt(t->md->disk))
		return -EINVAL;

	down_write(&t->devices_lock);

	dd = find_device(&t->devices, dev);
	if (!dd) {
		dd = kmalloc(sizeof(*dd), GFP_KERNEL);
		if (!dd) {
			r = -ENOMEM;
			goto unlock_ret_r;
		}

		r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev);
		if (r) {
			kfree(dd);
			goto unlock_ret_r;
		}

		refcount_set(&dd->count, 1);
		list_add(&dd->list, &t->devices);
		goto out;

	} else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
		r = upgrade_mode(dd, mode, t->md);
		if (r)
			goto unlock_ret_r;
	}
	refcount_inc(&dd->count);
out:
	up_write(&t->devices_lock);
	*result = dd->dm_dev;
	return 0;

unlock_ret_r:
	up_write(&t->devices_lock);
	return r;
}
EXPORT_SYMBOL(dm_get_device);

static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
				sector_t start, sector_t len, void *data)
{
	struct queue_limits *limits = data;
	struct block_device *bdev = dev->bdev;
	struct request_queue *q = bdev_get_queue(bdev);

	if (unlikely(!q)) {
		DMWARN("%s: Cannot set limits for nonexistent device %pg",
		       dm_device_name(ti->table->md), bdev);
		return 0;
	}

	if (blk_stack_limits(limits, &q->limits,
			get_start_sect(bdev) + start) < 0)
		DMWARN("%s: adding target device %pg caused an alignment inconsistency: "
		       "physical_block_size=%u, logical_block_size=%u, "
		       "alignment_offset=%u, start=%llu",
		       dm_device_name(ti->table->md), bdev,
		       q->limits.physical_block_size,
		       q->limits.logical_block_size,
		       q->limits.alignment_offset,
		       (unsigned long long) start << SECTOR_SHIFT);

	/*
	 * Only stack the integrity profile if the target doesn't have native
	 * integrity support.
	 */
	if (!dm_target_has_integrity(ti->type))
		queue_limits_stack_integrity_bdev(limits, bdev);
	return 0;
}

/*
 * Decrement a device's use count and remove it if necessary.
 */
void dm_put_device(struct dm_target *ti, struct dm_dev *d)
{
	int found = 0;
	struct dm_table *t = ti->table;
	struct list_head *devices = &t->devices;
	struct dm_dev_internal *dd;

	down_write(&t->devices_lock);

	list_for_each_entry(dd, devices, list) {
		if (dd->dm_dev == d) {
			found = 1;
			break;
		}
	}
	if (!found) {
		DMERR("%s: device %s not in table devices list",
		      dm_device_name(t->md), d->name);
		goto unlock_ret;
	}
	if (refcount_dec_and_test(&dd->count)) {
		dm_put_table_device(t->md, d);
		list_del(&dd->list);
		kfree(dd);
	}

unlock_ret:
	up_write(&t->devices_lock);
}
EXPORT_SYMBOL(dm_put_device);

/*
 * Checks to see if the target joins onto the end of the table.
 */
static int adjoin(struct dm_table *t, struct dm_target *ti)
{
	struct dm_target *prev;

	if (!t->num_targets)
		return !ti->begin;

	prev = &t->targets[t->num_targets - 1];
	return (ti->begin == (prev->begin + prev->len));
}

/*
 * Used to dynamically allocate the arg array.
 *
 * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
 * process messages even if some device is suspended. These messages have a
 * small fixed number of arguments.
 *
 * On the other hand, dm-switch needs to process bulk data using messages and
 * excessive use of GFP_NOIO could cause trouble.
 */
static char **realloc_argv(unsigned int *size, char **old_argv)
{
	char **argv;
	unsigned int new_size;
	gfp_t gfp;

	if (*size) {
		new_size = *size * 2;
		gfp = GFP_KERNEL;
	} else {
		new_size = 8;
		gfp = GFP_NOIO;
	}
	argv = kmalloc_array(new_size, sizeof(*argv), gfp);
	if (argv && old_argv) {
		memcpy(argv, old_argv, *size * sizeof(*argv));
		*size = new_size;
	}

	kfree(old_argv);
	return argv;
}

/*
 * Destructively splits up the argument list to pass to ctr.
 */
int dm_split_args(int *argc, char ***argvp, char *input)
{
	char *start, *end = input, *out, **argv = NULL;
	unsigned int array_size = 0;

	*argc = 0;

	if (!input) {
		*argvp = NULL;
		return 0;
	}

	argv = realloc_argv(&array_size, argv);
	if (!argv)
		return -ENOMEM;

	while (1) {
		/* Skip whitespace */
		start = skip_spaces(end);

		if (!*start)
			break;	/* success, we hit the end */

		/* 'out' is used to remove any back-quotes */
		end = out = start;
		while (*end) {
			/* Everything apart from '\0' can be quoted */
			if (*end == '\\' && *(end + 1)) {
				*out++ = *(end + 1);
				end += 2;
				continue;
			}

			if (isspace(*end))
				break;	/* end of token */

			*out++ = *end++;
		}

		/* have we already filled the array ? */
		if ((*argc + 1) > array_size) {
			argv = realloc_argv(&array_size, argv);
			if (!argv)
				return -ENOMEM;
		}

		/* we know this is whitespace */
		if (*end)
			end++;

		/* terminate the string and put it in the array */
		*out = '\0';
		argv[*argc] = start;
		(*argc)++;
	}

	*argvp = argv;
	return 0;
}

static void dm_set_stacking_limits(struct queue_limits *limits)
{
	blk_set_stacking_limits(limits);
	limits->features |= BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT | BLK_FEAT_POLL;
}

/*
 * Impose necessary and sufficient conditions on a devices's table such
 * that any incoming bio which respects its logical_block_size can be
 * processed successfully.  If it falls across the boundary between
 * two or more targets, the size of each piece it gets split into must
 * be compatible with the logical_block_size of the target processing it.
 */
static int validate_hardware_logical_block_alignment(struct dm_table *t,
						     struct queue_limits *limits)
{
	/*
	 * This function uses arithmetic modulo the logical_block_size
	 * (in units of 512-byte sectors).
	 */
	unsigned short device_logical_block_size_sects =
		limits->logical_block_size >> SECTOR_SHIFT;

	/*
	 * Offset of the start of the next table entry, mod logical_block_size.
	 */
	unsigned short next_target_start = 0;

	/*
	 * Given an aligned bio that extends beyond the end of a
	 * target, how many sectors must the next target handle?
	 */
	unsigned short remaining = 0;

	struct dm_target *ti;
	struct queue_limits ti_limits;
	unsigned int i;

	/*
	 * Check each entry in the table in turn.
	 */
	for (i = 0; i < t->num_targets; i++) {
		ti = dm_table_get_target(t, i);

		dm_set_stacking_limits(&ti_limits);

		/* combine all target devices' limits */
		if (ti->type->iterate_devices)
			ti->type->iterate_devices(ti, dm_set_device_limits,
						  &ti_limits);

		/*
		 * If the remaining sectors fall entirely within this
		 * table entry are they compatible with its logical_block_size?
		 */
		if (remaining < ti->len &&
		    remaining & ((ti_limits.logical_block_size >>
				  SECTOR_SHIFT) - 1))
			break;	/* Error */

		next_target_start =
		    (unsigned short) ((next_target_start + ti->len) &
				      (device_logical_block_size_sects - 1));
		remaining = next_target_start ?
		    device_logical_block_size_sects - next_target_start : 0;
	}

	if (remaining) {
		DMERR("%s: table line %u (start sect %llu len %llu) "
		      "not aligned to h/w logical block size %u",
		      dm_device_name(t->md), i,
		      (unsigned long long) ti->begin,
		      (unsigned long long) ti->len,
		      limits->logical_block_size);
		return -EINVAL;
	}

	return 0;
}

int dm_table_add_target(struct dm_table *t, const char *type,
			sector_t start, sector_t len, char *params)
{
	int r = -EINVAL, argc;
	char **argv;
	struct dm_target *ti;

	if (t->singleton) {
		DMERR("%s: target type %s must appear alone in table",
		      dm_device_name(t->md), t->targets->type->name);
		return -EINVAL;
	}

	BUG_ON(t->num_targets >= t->num_allocated);

	ti = t->targets + t->num_targets;
	memset(ti, 0, sizeof(*ti));

	if (!len) {
		DMERR("%s: zero-length target", dm_device_name(t->md));
		return -EINVAL;
	}

	ti->type = dm_get_target_type(type);
	if (!ti->type) {
		DMERR("%s: %s: unknown target type", dm_device_name(t->md), type);
		return -EINVAL;
	}

	if (dm_target_needs_singleton(ti->type)) {
		if (t->num_targets) {
			ti->error = "singleton target type must appear alone in table";
			goto bad;
		}
		t->singleton = true;
	}

	if (dm_target_always_writeable(ti->type) &&
	    !(t->mode & BLK_OPEN_WRITE)) {
		ti->error = "target type may not be included in a read-only table";
		goto bad;
	}

	if (t->immutable_target_type) {
		if (t->immutable_target_type != ti->type) {
			ti->error = "immutable target type cannot be mixed with other target types";
			goto bad;
		}
	} else if (dm_target_is_immutable(ti->type)) {
		if (t->num_targets) {
			ti->error = "immutable target type cannot be mixed with other target types";
			goto bad;
		}
		t->immutable_target_type = ti->type;
	}

	ti->table = t;
	ti->begin = start;
	ti->len = len;
	ti->error = "Unknown error";

	/*
	 * Does this target adjoin the previous one ?
	 */
	if (!adjoin(t, ti)) {
		ti->error = "Gap in table";
		goto bad;
	}

	r = dm_split_args(&argc, &argv, params);
	if (r) {
		ti->error = "couldn't split parameters";
		goto bad;
	}

	r = ti->type->ctr(ti, argc, argv);
	kfree(argv);
	if (r)
		goto bad;

	t->highs[t->num_targets++] = ti->begin + ti->len - 1;

	if (!ti->num_discard_bios && ti->discards_supported)
		DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
		       dm_device_name(t->md), type);

	if (ti->limit_swap_bios && !static_key_enabled(&swap_bios_enabled.key))
		static_branch_enable(&swap_bios_enabled);

	if (!ti->flush_bypasses_map)
		t->flush_bypasses_map = false;

	return 0;

 bad:
	DMERR("%s: %s: %s (%pe)", dm_device_name(t->md), type, ti->error, ERR_PTR(r));
	dm_put_target_type(ti->type);
	return r;
}

/*
 * Target argument parsing helpers.
 */
static int validate_next_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set,
			     unsigned int *value, char **error, unsigned int grouped)
{
	const char *arg_str = dm_shift_arg(arg_set);
	char dummy;

	if (!arg_str ||
	    (sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
	    (*value < arg->min) ||
	    (*value > arg->max) ||
	    (grouped && arg_set->argc < *value)) {
		*error = arg->error;
		return -EINVAL;
	}

	return 0;
}

int dm_read_arg(const struct dm_arg *arg, struct dm_arg_set *arg_set,
		unsigned int *value, char **error)
{
	return validate_next_arg(arg, arg_set, value, error, 0);
}
EXPORT_SYMBOL(dm_read_arg);

int dm_read_arg_group(const struct dm_arg *arg, struct dm_arg_set *arg_set,
		      unsigned int *value, char **error)
{
	return validate_next_arg(arg, arg_set, value, error, 1);
}
EXPORT_SYMBOL(dm_read_arg_group);

const char *dm_shift_arg(struct dm_arg_set *as)
{
	char *r;

	if (as->argc) {
		as->argc--;
		r = *as->argv;
		as->argv++;
		return r;
	}

	return NULL;
}
EXPORT_SYMBOL(dm_shift_arg);

void dm_consume_args(struct dm_arg_set *as, unsigned int num_args)
{
	BUG_ON(as->argc < num_args);
	as->argc -= num_args;
	as->argv += num_args;
}
EXPORT_SYMBOL(dm_consume_args);

static bool __table_type_bio_based(enum dm_queue_mode table_type)
{
	return (table_type == DM_TYPE_BIO_BASED ||
		table_type == DM_TYPE_DAX_BIO_BASED);
}

static bool __table_type_request_based(enum dm_queue_mode table_type)
{
	return table_type == DM_TYPE_REQUEST_BASED;
}

void dm_table_set_type(struct dm_table *t, enum dm_queue_mode type)
{
	t->type = type;
}
EXPORT_SYMBOL_GPL(dm_table_set_type);

/* validate the dax capability of the target device span */
static int device_not_dax_capable(struct dm_target *ti, struct dm_dev *dev,
			sector_t start, sector_t len, void *data)
{
	if (dev->dax_dev)
		return false;

	DMDEBUG("%pg: error: dax unsupported by block device", dev->bdev);
	return true;
}

/* Check devices support synchronous DAX */
static int device_not_dax_synchronous_capable(struct dm_target *ti, struct dm_dev *dev,
					      sector_t start, sector_t len, void *data)
{
	return !dev->dax_dev || !dax_synchronous(dev->dax_dev);
}

static bool dm_table_supports_dax(struct dm_table *t,
				  iterate_devices_callout_fn iterate_fn)
{
	/* Ensure that all targets support DAX. */
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (!ti->type->direct_access)
			return false;

		if (dm_target_is_wildcard(ti->type) ||
		    !ti->type->iterate_devices ||
		    ti->type->iterate_devices(ti, iterate_fn, NULL))
			return false;
	}

	return true;
}

static int device_is_rq_stackable(struct dm_target *ti, struct dm_dev *dev,
				  sector_t start, sector_t len, void *data)
{
	struct block_device *bdev = dev->bdev;
	struct request_queue *q = bdev_get_queue(bdev);

	/* request-based cannot stack on partitions! */
	if (bdev_is_partition(bdev))
		return false;

	return queue_is_mq(q);
}

static int dm_table_determine_type(struct dm_table *t)
{
	unsigned int bio_based = 0, request_based = 0, hybrid = 0;
	struct dm_target *ti;
	struct list_head *devices = dm_table_get_devices(t);
	enum dm_queue_mode live_md_type = dm_get_md_type(t->md);

	if (t->type != DM_TYPE_NONE) {
		/* target already set the table's type */
		if (t->type == DM_TYPE_BIO_BASED) {
			/* possibly upgrade to a variant of bio-based */
			goto verify_bio_based;
		}
		BUG_ON(t->type == DM_TYPE_DAX_BIO_BASED);
		goto verify_rq_based;
	}

	for (unsigned int i = 0; i < t->num_targets; i++) {
		ti = dm_table_get_target(t, i);
		if (dm_target_hybrid(ti))
			hybrid = 1;
		else if (dm_target_request_based(ti))
			request_based = 1;
		else
			bio_based = 1;

		if (bio_based && request_based) {
			DMERR("Inconsistent table: different target types can't be mixed up");
			return -EINVAL;
		}
	}

	if (hybrid && !bio_based && !request_based) {
		/*
		 * The targets can work either way.
		 * Determine the type from the live device.
		 * Default to bio-based if device is new.
		 */
		if (__table_type_request_based(live_md_type))
			request_based = 1;
		else
			bio_based = 1;
	}

	if (bio_based) {
verify_bio_based:
		/* We must use this table as bio-based */
		t->type = DM_TYPE_BIO_BASED;
		if (dm_table_supports_dax(t, device_not_dax_capable) ||
		    (list_empty(devices) && live_md_type == DM_TYPE_DAX_BIO_BASED)) {
			t->type = DM_TYPE_DAX_BIO_BASED;
		}
		return 0;
	}

	BUG_ON(!request_based); /* No targets in this table */

	t->type = DM_TYPE_REQUEST_BASED;

verify_rq_based:
	/*
	 * Request-based dm supports only tables that have a single target now.
	 * To support multiple targets, request splitting support is needed,
	 * and that needs lots of changes in the block-layer.
	 * (e.g. request completion process for partial completion.)
	 */
	if (t->num_targets > 1) {
		DMERR("request-based DM doesn't support multiple targets");
		return -EINVAL;
	}

	if (list_empty(devices)) {
		int srcu_idx;
		struct dm_table *live_table = dm_get_live_table(t->md, &srcu_idx);

		/* inherit live table's type */
		if (live_table)
			t->type = live_table->type;
		dm_put_live_table(t->md, srcu_idx);
		return 0;
	}

	ti = dm_table_get_immutable_target(t);
	if (!ti) {
		DMERR("table load rejected: immutable target is required");
		return -EINVAL;
	} else if (ti->max_io_len) {
		DMERR("table load rejected: immutable target that splits IO is not supported");
		return -EINVAL;
	}

	/* Non-request-stackable devices can't be used for request-based dm */
	if (!ti->type->iterate_devices ||
	    !ti->type->iterate_devices(ti, device_is_rq_stackable, NULL)) {
		DMERR("table load rejected: including non-request-stackable devices");
		return -EINVAL;
	}

	return 0;
}

enum dm_queue_mode dm_table_get_type(struct dm_table *t)
{
	return t->type;
}

struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
{
	return t->immutable_target_type;
}

struct dm_target *dm_table_get_immutable_target(struct dm_table *t)
{
	/* Immutable target is implicitly a singleton */
	if (t->num_targets > 1 ||
	    !dm_target_is_immutable(t->targets[0].type))
		return NULL;

	return t->targets;
}

struct dm_target *dm_table_get_wildcard_target(struct dm_table *t)
{
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (dm_target_is_wildcard(ti->type))
			return ti;
	}

	return NULL;
}

bool dm_table_bio_based(struct dm_table *t)
{
	return __table_type_bio_based(dm_table_get_type(t));
}

bool dm_table_request_based(struct dm_table *t)
{
	return __table_type_request_based(dm_table_get_type(t));
}

static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
{
	enum dm_queue_mode type = dm_table_get_type(t);
	unsigned int per_io_data_size = 0, front_pad, io_front_pad;
	unsigned int min_pool_size = 0, pool_size;
	struct dm_md_mempools *pools;
	unsigned int bioset_flags = 0;

	if (unlikely(type == DM_TYPE_NONE)) {
		DMERR("no table type is set, can't allocate mempools");
		return -EINVAL;
	}

	pools = kzalloc_node(sizeof(*pools), GFP_KERNEL, md->numa_node_id);
	if (!pools)
		return -ENOMEM;

	if (type == DM_TYPE_REQUEST_BASED) {
		pool_size = dm_get_reserved_rq_based_ios();
		front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
		goto init_bs;
	}

	if (md->queue->limits.features & BLK_FEAT_POLL)
		bioset_flags |= BIOSET_PERCPU_CACHE;

	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		per_io_data_size = max(per_io_data_size, ti->per_io_data_size);
		min_pool_size = max(min_pool_size, ti->num_flush_bios);
	}
	pool_size = max(dm_get_reserved_bio_based_ios(), min_pool_size);
	front_pad = roundup(per_io_data_size,
		__alignof__(struct dm_target_io)) + DM_TARGET_IO_BIO_OFFSET;

	io_front_pad = roundup(per_io_data_size,
		__alignof__(struct dm_io)) + DM_IO_BIO_OFFSET;
	if (bioset_init(&pools->io_bs, pool_size, io_front_pad, bioset_flags))
		goto out_free_pools;
	if (t->integrity_supported &&
	    bioset_integrity_create(&pools->io_bs, pool_size))
		goto out_free_pools;
init_bs:
	if (bioset_init(&pools->bs, pool_size, front_pad, 0))
		goto out_free_pools;
	if (t->integrity_supported &&
	    bioset_integrity_create(&pools->bs, pool_size))
		goto out_free_pools;

	t->mempools = pools;
	return 0;

out_free_pools:
	dm_free_md_mempools(pools);
	return -ENOMEM;
}

static int setup_indexes(struct dm_table *t)
{
	int i;
	unsigned int total = 0;
	sector_t *indexes;

	/* allocate the space for *all* the indexes */
	for (i = t->depth - 2; i >= 0; i--) {
		t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
		total += t->counts[i];
	}

	indexes = kvcalloc(total, NODE_SIZE, GFP_KERNEL);
	if (!indexes)
		return -ENOMEM;

	/* set up internal nodes, bottom-up */
	for (i = t->depth - 2; i >= 0; i--) {
		t->index[i] = indexes;
		indexes += (KEYS_PER_NODE * t->counts[i]);
		setup_btree_index(i, t);
	}

	return 0;
}

/*
 * Builds the btree to index the map.
 */
static int dm_table_build_index(struct dm_table *t)
{
	int r = 0;
	unsigned int leaf_nodes;

	/* how many indexes will the btree have ? */
	leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
	t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);

	/* leaf layer has already been set up */
	t->counts[t->depth - 1] = leaf_nodes;
	t->index[t->depth - 1] = t->highs;

	if (t->depth >= 2)
		r = setup_indexes(t);

	return r;
}

#ifdef CONFIG_BLK_INLINE_ENCRYPTION

struct dm_crypto_profile {
	struct blk_crypto_profile profile;
	struct mapped_device *md;
};

static int dm_keyslot_evict_callback(struct dm_target *ti, struct dm_dev *dev,
				     sector_t start, sector_t len, void *data)
{
	const struct blk_crypto_key *key = data;

	blk_crypto_evict_key(dev->bdev, key);
	return 0;
}

/*
 * When an inline encryption key is evicted from a device-mapper device, evict
 * it from all the underlying devices.
 */
static int dm_keyslot_evict(struct blk_crypto_profile *profile,
			    const struct blk_crypto_key *key, unsigned int slot)
{
	struct mapped_device *md =
		container_of(profile, struct dm_crypto_profile, profile)->md;
	struct dm_table *t;
	int srcu_idx;

	t = dm_get_live_table(md, &srcu_idx);
	if (!t)
		return 0;

	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (!ti->type->iterate_devices)
			continue;
		ti->type->iterate_devices(ti, dm_keyslot_evict_callback,
					  (void *)key);
	}

	dm_put_live_table(md, srcu_idx);
	return 0;
}

static int
device_intersect_crypto_capabilities(struct dm_target *ti, struct dm_dev *dev,
				     sector_t start, sector_t len, void *data)
{
	struct blk_crypto_profile *parent = data;
	struct blk_crypto_profile *child =
		bdev_get_queue(dev->bdev)->crypto_profile;

	blk_crypto_intersect_capabilities(parent, child);
	return 0;
}

void dm_destroy_crypto_profile(struct blk_crypto_profile *profile)
{
	struct dm_crypto_profile *dmcp = container_of(profile,
						      struct dm_crypto_profile,
						      profile);

	if (!profile)
		return;

	blk_crypto_profile_destroy(profile);
	kfree(dmcp);
}

static void dm_table_destroy_crypto_profile(struct dm_table *t)
{
	dm_destroy_crypto_profile(t->crypto_profile);
	t->crypto_profile = NULL;
}

/*
 * Constructs and initializes t->crypto_profile with a crypto profile that
 * represents the common set of crypto capabilities of the devices described by
 * the dm_table.  However, if the constructed crypto profile doesn't support all
 * crypto capabilities that are supported by the current mapped_device, it
 * returns an error instead, since we don't support removing crypto capabilities
 * on table changes.  Finally, if the constructed crypto profile is "empty" (has
 * no crypto capabilities at all), it just sets t->crypto_profile to NULL.
 */
static int dm_table_construct_crypto_profile(struct dm_table *t)
{
	struct dm_crypto_profile *dmcp;
	struct blk_crypto_profile *profile;
	unsigned int i;
	bool empty_profile = true;

	dmcp = kmalloc(sizeof(*dmcp), GFP_KERNEL);
	if (!dmcp)
		return -ENOMEM;
	dmcp->md = t->md;

	profile = &dmcp->profile;
	blk_crypto_profile_init(profile, 0);
	profile->ll_ops.keyslot_evict = dm_keyslot_evict;
	profile->max_dun_bytes_supported = UINT_MAX;
	memset(profile->modes_supported, 0xFF,
	       sizeof(profile->modes_supported));

	for (i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (!dm_target_passes_crypto(ti->type)) {
			blk_crypto_intersect_capabilities(profile, NULL);
			break;
		}
		if (!ti->type->iterate_devices)
			continue;
		ti->type->iterate_devices(ti,
					  device_intersect_crypto_capabilities,
					  profile);
	}

	if (t->md->queue &&
	    !blk_crypto_has_capabilities(profile,
					 t->md->queue->crypto_profile)) {
		DMERR("Inline encryption capabilities of new DM table were more restrictive than the old table's. This is not supported!");
		dm_destroy_crypto_profile(profile);
		return -EINVAL;
	}

	/*
	 * If the new profile doesn't actually support any crypto capabilities,
	 * we may as well represent it with a NULL profile.
	 */
	for (i = 0; i < ARRAY_SIZE(profile->modes_supported); i++) {
		if (profile->modes_supported[i]) {
			empty_profile = false;
			break;
		}
	}

	if (empty_profile) {
		dm_destroy_crypto_profile(profile);
		profile = NULL;
	}

	/*
	 * t->crypto_profile is only set temporarily while the table is being
	 * set up, and it gets set to NULL after the profile has been
	 * transferred to the request_queue.
	 */
	t->crypto_profile = profile;

	return 0;
}

static void dm_update_crypto_profile(struct request_queue *q,
				     struct dm_table *t)
{
	if (!t->crypto_profile)
		return;

	/* Make the crypto profile less restrictive. */
	if (!q->crypto_profile) {
		blk_crypto_register(t->crypto_profile, q);
	} else {
		blk_crypto_update_capabilities(q->crypto_profile,
					       t->crypto_profile);
		dm_destroy_crypto_profile(t->crypto_profile);
	}
	t->crypto_profile = NULL;
}

#else /* CONFIG_BLK_INLINE_ENCRYPTION */

static int dm_table_construct_crypto_profile(struct dm_table *t)
{
	return 0;
}

void dm_destroy_crypto_profile(struct blk_crypto_profile *profile)
{
}

static void dm_table_destroy_crypto_profile(struct dm_table *t)
{
}

static void dm_update_crypto_profile(struct request_queue *q,
				     struct dm_table *t)
{
}

#endif /* !CONFIG_BLK_INLINE_ENCRYPTION */

/*
 * Prepares the table for use by building the indices,
 * setting the type, and allocating mempools.
 */
int dm_table_complete(struct dm_table *t)
{
	int r;

	r = dm_table_determine_type(t);
	if (r) {
		DMERR("unable to determine table type");
		return r;
	}

	r = dm_table_build_index(t);
	if (r) {
		DMERR("unable to build btrees");
		return r;
	}

	r = dm_table_construct_crypto_profile(t);
	if (r) {
		DMERR("could not construct crypto profile.");
		return r;
	}

	r = dm_table_alloc_md_mempools(t, t->md);
	if (r)
		DMERR("unable to allocate mempools");

	return r;
}

static DEFINE_MUTEX(_event_lock);
void dm_table_event_callback(struct dm_table *t,
			     void (*fn)(void *), void *context)
{
	mutex_lock(&_event_lock);
	t->event_fn = fn;
	t->event_context = context;
	mutex_unlock(&_event_lock);
}

void dm_table_event(struct dm_table *t)
{
	mutex_lock(&_event_lock);
	if (t->event_fn)
		t->event_fn(t->event_context);
	mutex_unlock(&_event_lock);
}
EXPORT_SYMBOL(dm_table_event);

inline sector_t dm_table_get_size(struct dm_table *t)
{
	return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
}
EXPORT_SYMBOL(dm_table_get_size);

/*
 * Search the btree for the correct target.
 *
 * Caller should check returned pointer for NULL
 * to trap I/O beyond end of device.
 */
struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
{
	unsigned int l, n = 0, k = 0;
	sector_t *node;

	if (unlikely(sector >= dm_table_get_size(t)))
		return NULL;

	for (l = 0; l < t->depth; l++) {
		n = get_child(n, k);
		node = get_node(t, l, n);

		for (k = 0; k < KEYS_PER_NODE; k++)
			if (node[k] >= sector)
				break;
	}

	return &t->targets[(KEYS_PER_NODE * n) + k];
}

/*
 * type->iterate_devices() should be called when the sanity check needs to
 * iterate and check all underlying data devices. iterate_devices() will
 * iterate all underlying data devices until it encounters a non-zero return
 * code, returned by whether the input iterate_devices_callout_fn, or
 * iterate_devices() itself internally.
 *
 * For some target type (e.g. dm-stripe), one call of iterate_devices() may
 * iterate multiple underlying devices internally, in which case a non-zero
 * return code returned by iterate_devices_callout_fn will stop the iteration
 * in advance.
 *
 * Cases requiring _any_ underlying device supporting some kind of attribute,
 * should use the iteration structure like dm_table_any_dev_attr(), or call
 * it directly. @func should handle semantics of positive examples, e.g.
 * capable of something.
 *
 * Cases requiring _all_ underlying devices supporting some kind of attribute,
 * should use the iteration structure like dm_table_supports_nowait() or
 * dm_table_supports_discards(). Or introduce dm_table_all_devs_attr() that
 * uses an @anti_func that handle semantics of counter examples, e.g. not
 * capable of something. So: return !dm_table_any_dev_attr(t, anti_func, data);
 */
static bool dm_table_any_dev_attr(struct dm_table *t,
				  iterate_devices_callout_fn func, void *data)
{
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (ti->type->iterate_devices &&
		    ti->type->iterate_devices(ti, func, data))
			return true;
	}

	return false;
}

static int count_device(struct dm_target *ti, struct dm_dev *dev,
			sector_t start, sector_t len, void *data)
{
	unsigned int *num_devices = data;

	(*num_devices)++;

	return 0;
}

/*
 * Check whether a table has no data devices attached using each
 * target's iterate_devices method.
 * Returns false if the result is unknown because a target doesn't
 * support iterate_devices.
 */
bool dm_table_has_no_data_devices(struct dm_table *t)
{
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);
		unsigned int num_devices = 0;

		if (!ti->type->iterate_devices)
			return false;

		ti->type->iterate_devices(ti, count_device, &num_devices);
		if (num_devices)
			return false;
	}

	return true;
}

static int device_not_zoned(struct dm_target *ti, struct dm_dev *dev,
			    sector_t start, sector_t len, void *data)
{
	bool *zoned = data;

	return bdev_is_zoned(dev->bdev) != *zoned;
}

static int device_is_zoned_model(struct dm_target *ti, struct dm_dev *dev,
				 sector_t start, sector_t len, void *data)
{
	return bdev_is_zoned(dev->bdev);
}

/*
 * Check the device zoned model based on the target feature flag. If the target
 * has the DM_TARGET_ZONED_HM feature flag set, host-managed zoned devices are
 * also accepted but all devices must have the same zoned model. If the target
 * has the DM_TARGET_MIXED_ZONED_MODEL feature set, the devices can have any
 * zoned model with all zoned devices having the same zone size.
 */
static bool dm_table_supports_zoned(struct dm_table *t, bool zoned)
{
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		/*
		 * For the wildcard target (dm-error), if we do not have a
		 * backing device, we must always return false. If we have a
		 * backing device, the result must depend on checking zoned
		 * model, like for any other target. So for this, check directly
		 * if the target backing device is zoned as we get "false" when
		 * dm-error was set without a backing device.
		 */
		if (dm_target_is_wildcard(ti->type) &&
		    !ti->type->iterate_devices(ti, device_is_zoned_model, NULL))
			return false;

		if (dm_target_supports_zoned_hm(ti->type)) {
			if (!ti->type->iterate_devices ||
			    ti->type->iterate_devices(ti, device_not_zoned,
						      &zoned))
				return false;
		} else if (!dm_target_supports_mixed_zoned_model(ti->type)) {
			if (zoned)
				return false;
		}
	}

	return true;
}

static int device_not_matches_zone_sectors(struct dm_target *ti, struct dm_dev *dev,
					   sector_t start, sector_t len, void *data)
{
	unsigned int *zone_sectors = data;

	if (!bdev_is_zoned(dev->bdev))
		return 0;
	return bdev_zone_sectors(dev->bdev) != *zone_sectors;
}

/*
 * Check consistency of zoned model and zone sectors across all targets. For
 * zone sectors, if the destination device is a zoned block device, it shall
 * have the specified zone_sectors.
 */
static int validate_hardware_zoned(struct dm_table *t, bool zoned,
				   unsigned int zone_sectors)
{
	if (!zoned)
		return 0;

	if (!dm_table_supports_zoned(t, zoned)) {
		DMERR("%s: zoned model is not consistent across all devices",
		      dm_device_name(t->md));
		return -EINVAL;
	}

	/* Check zone size validity and compatibility */
	if (!zone_sectors || !is_power_of_2(zone_sectors))
		return -EINVAL;

	if (dm_table_any_dev_attr(t, device_not_matches_zone_sectors, &zone_sectors)) {
		DMERR("%s: zone sectors is not consistent across all zoned devices",
		      dm_device_name(t->md));
		return -EINVAL;
	}

	return 0;
}

/*
 * Establish the new table's queue_limits and validate them.
 */
int dm_calculate_queue_limits(struct dm_table *t,
			      struct queue_limits *limits)
{
	struct queue_limits ti_limits;
	unsigned int zone_sectors = 0;
	bool zoned = false;

	dm_set_stacking_limits(limits);

	t->integrity_supported = true;
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (!dm_target_passes_integrity(ti->type))
			t->integrity_supported = false;
	}

	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		dm_set_stacking_limits(&ti_limits);

		if (!ti->type->iterate_devices) {
			/* Set I/O hints portion of queue limits */
			if (ti->type->io_hints)
				ti->type->io_hints(ti, &ti_limits);
			goto combine_limits;
		}

		/*
		 * Combine queue limits of all the devices this target uses.
		 */
		ti->type->iterate_devices(ti, dm_set_device_limits,
					  &ti_limits);

		if (!zoned && (ti_limits.features & BLK_FEAT_ZONED)) {
			/*
			 * After stacking all limits, validate all devices
			 * in table support this zoned model and zone sectors.
			 */
			zoned = (ti_limits.features & BLK_FEAT_ZONED);
			zone_sectors = ti_limits.chunk_sectors;
		}

		/* Set I/O hints portion of queue limits */
		if (ti->type->io_hints)
			ti->type->io_hints(ti, &ti_limits);

		/*
		 * Check each device area is consistent with the target's
		 * overall queue limits.
		 */
		if (ti->type->iterate_devices(ti, device_area_is_invalid,
					      &ti_limits))
			return -EINVAL;

combine_limits:
		/*
		 * Merge this target's queue limits into the overall limits
		 * for the table.
		 */
		if (blk_stack_limits(limits, &ti_limits, 0) < 0)
			DMWARN("%s: adding target device (start sect %llu len %llu) "
			       "caused an alignment inconsistency",
			       dm_device_name(t->md),
			       (unsigned long long) ti->begin,
			       (unsigned long long) ti->len);

		if (t->integrity_supported ||
		    dm_target_has_integrity(ti->type)) {
			if (!queue_limits_stack_integrity(limits, &ti_limits)) {
				DMWARN("%s: adding target device (start sect %llu len %llu) "
				       "disabled integrity support due to incompatibility",
				       dm_device_name(t->md),
				       (unsigned long long) ti->begin,
				       (unsigned long long) ti->len);
				t->integrity_supported = false;
			}
		}
	}

	/*
	 * Verify that the zoned model and zone sectors, as determined before
	 * any .io_hints override, are the same across all devices in the table.
	 * - this is especially relevant if .io_hints is emulating a disk-managed
	 *   zoned model on host-managed zoned block devices.
	 * BUT...
	 */
	if (limits->features & BLK_FEAT_ZONED) {
		/*
		 * ...IF the above limits stacking determined a zoned model
		 * validate that all of the table's devices conform to it.
		 */
		zoned = limits->features & BLK_FEAT_ZONED;
		zone_sectors = limits->chunk_sectors;
	}
	if (validate_hardware_zoned(t, zoned, zone_sectors))
		return -EINVAL;

	return validate_hardware_logical_block_alignment(t, limits);
}

/*
 * Check if a target requires flush support even if none of the underlying
 * devices need it (e.g. to persist target-specific metadata).
 */
static bool dm_table_supports_flush(struct dm_table *t)
{
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (ti->num_flush_bios && ti->flush_supported)
			return true;
	}

	return false;
}

static int device_dax_write_cache_enabled(struct dm_target *ti,
					  struct dm_dev *dev, sector_t start,
					  sector_t len, void *data)
{
	struct dax_device *dax_dev = dev->dax_dev;

	if (!dax_dev)
		return false;

	if (dax_write_cache_enabled(dax_dev))
		return true;
	return false;
}

static int device_not_write_zeroes_capable(struct dm_target *ti, struct dm_dev *dev,
					   sector_t start, sector_t len, void *data)
{
	struct request_queue *q = bdev_get_queue(dev->bdev);

	return !q->limits.max_write_zeroes_sectors;
}

static bool dm_table_supports_write_zeroes(struct dm_table *t)
{
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (!ti->num_write_zeroes_bios)
			return false;

		if (!ti->type->iterate_devices ||
		    ti->type->iterate_devices(ti, device_not_write_zeroes_capable, NULL))
			return false;
	}

	return true;
}

static bool dm_table_supports_nowait(struct dm_table *t)
{
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (!dm_target_supports_nowait(ti->type))
			return false;
	}

	return true;
}

static int device_not_discard_capable(struct dm_target *ti, struct dm_dev *dev,
				      sector_t start, sector_t len, void *data)
{
	return !bdev_max_discard_sectors(dev->bdev);
}

static bool dm_table_supports_discards(struct dm_table *t)
{
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (!ti->num_discard_bios)
			return false;

		/*
		 * Either the target provides discard support (as implied by setting
		 * 'discards_supported') or it relies on _all_ data devices having
		 * discard support.
		 */
		if (!ti->discards_supported &&
		    (!ti->type->iterate_devices ||
		     ti->type->iterate_devices(ti, device_not_discard_capable, NULL)))
			return false;
	}

	return true;
}

static int device_not_secure_erase_capable(struct dm_target *ti,
					   struct dm_dev *dev, sector_t start,
					   sector_t len, void *data)
{
	return !bdev_max_secure_erase_sectors(dev->bdev);
}

static bool dm_table_supports_secure_erase(struct dm_table *t)
{
	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (!ti->num_secure_erase_bios)
			return false;

		if (!ti->type->iterate_devices ||
		    ti->type->iterate_devices(ti, device_not_secure_erase_capable, NULL))
			return false;
	}

	return true;
}

int dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
			      struct queue_limits *limits)
{
	int r;

	if (!dm_table_supports_nowait(t))
		limits->features &= ~BLK_FEAT_NOWAIT;

	/*
	 * The current polling impementation does not support request based
	 * stacking.
	 */
	if (!__table_type_bio_based(t->type))
		limits->features &= ~BLK_FEAT_POLL;

	if (!dm_table_supports_discards(t)) {
		limits->max_hw_discard_sectors = 0;
		limits->discard_granularity = 0;
		limits->discard_alignment = 0;
	}

	if (!dm_table_supports_write_zeroes(t))
		limits->max_write_zeroes_sectors = 0;

	if (!dm_table_supports_secure_erase(t))
		limits->max_secure_erase_sectors = 0;

	if (dm_table_supports_flush(t))
		limits->features |= BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA;

	if (dm_table_supports_dax(t, device_not_dax_capable)) {
		limits->features |= BLK_FEAT_DAX;
		if (dm_table_supports_dax(t, device_not_dax_synchronous_capable))
			set_dax_synchronous(t->md->dax_dev);
	} else
		limits->features &= ~BLK_FEAT_DAX;

	if (dm_table_any_dev_attr(t, device_dax_write_cache_enabled, NULL))
		dax_write_cache(t->md->dax_dev, true);

	/* For a zoned table, setup the zone related queue attributes. */
	if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
	    (limits->features & BLK_FEAT_ZONED)) {
		r = dm_set_zones_restrictions(t, q, limits);
		if (r)
			return r;
	}

	r = queue_limits_set(q, limits);
	if (r)
		return r;

	/*
	 * Now that the limits are set, check the zones mapped by the table
	 * and setup the resources for zone append emulation if necessary.
	 */
	if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
	    (limits->features & BLK_FEAT_ZONED)) {
		r = dm_revalidate_zones(t, q);
		if (r)
			return r;
	}

	dm_update_crypto_profile(q, t);
	return 0;
}

struct list_head *dm_table_get_devices(struct dm_table *t)
{
	return &t->devices;
}

blk_mode_t dm_table_get_mode(struct dm_table *t)
{
	return t->mode;
}
EXPORT_SYMBOL(dm_table_get_mode);

enum suspend_mode {
	PRESUSPEND,
	PRESUSPEND_UNDO,
	POSTSUSPEND,
};

static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
{
	lockdep_assert_held(&t->md->suspend_lock);

	for (unsigned int i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		switch (mode) {
		case PRESUSPEND:
			if (ti->type->presuspend)
				ti->type->presuspend(ti);
			break;
		case PRESUSPEND_UNDO:
			if (ti->type->presuspend_undo)
				ti->type->presuspend_undo(ti);
			break;
		case POSTSUSPEND:
			if (ti->type->postsuspend)
				ti->type->postsuspend(ti);
			break;
		}
	}
}

void dm_table_presuspend_targets(struct dm_table *t)
{
	if (!t)
		return;

	suspend_targets(t, PRESUSPEND);
}

void dm_table_presuspend_undo_targets(struct dm_table *t)
{
	if (!t)
		return;

	suspend_targets(t, PRESUSPEND_UNDO);
}

void dm_table_postsuspend_targets(struct dm_table *t)
{
	if (!t)
		return;

	suspend_targets(t, POSTSUSPEND);
}

int dm_table_resume_targets(struct dm_table *t)
{
	unsigned int i;
	int r = 0;

	lockdep_assert_held(&t->md->suspend_lock);

	for (i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (!ti->type->preresume)
			continue;

		r = ti->type->preresume(ti);
		if (r) {
			DMERR("%s: %s: preresume failed, error = %d",
			      dm_device_name(t->md), ti->type->name, r);
			return r;
		}
	}

	for (i = 0; i < t->num_targets; i++) {
		struct dm_target *ti = dm_table_get_target(t, i);

		if (ti->type->resume)
			ti->type->resume(ti);
	}

	return 0;
}

struct mapped_device *dm_table_get_md(struct dm_table *t)
{
	return t->md;
}
EXPORT_SYMBOL(dm_table_get_md);

const char *dm_table_device_name(struct dm_table *t)
{
	return dm_device_name(t->md);
}
EXPORT_SYMBOL_GPL(dm_table_device_name);

void dm_table_run_md_queue_async(struct dm_table *t)
{
	if (!dm_table_request_based(t))
		return;

	if (t->md->queue)
		blk_mq_run_hw_queues(t->md->queue, true);
}
EXPORT_SYMBOL(dm_table_run_md_queue_async);