Initial import

1 files changed, 1707 insertions, 0 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
new file mode 100644
index 000000000..16ba55ad7
--- /dev/null
+++ b/drivers/md/dm-table.c
@@ -0,0 +1,1707 @@
+/*
+ * 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.h"
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/blkdev.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>
+
+#define DM_MSG_PREFIX "table"
+
+#define MAX_DEPTH 16
+#define NODE_SIZE L1_CACHE_BYTES
+#define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
+#define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
+
+struct dm_table {
+	struct mapped_device *md;
+	unsigned type;
+
+	/* btree table */
+	unsigned int depth;
+	unsigned int counts[MAX_DEPTH];	/* in nodes */
+	sector_t *index[MAX_DEPTH];
+
+	unsigned int num_targets;
+	unsigned int num_allocated;
+	sector_t *highs;
+	struct dm_target *targets;
+
+	struct target_type *immutable_target_type;
+	unsigned integrity_supported:1;
+	unsigned singleton:1;
+
+	/*
+	 * Indicates the rw permissions for the new logical
+	 * device.  This should be a combination of FMODE_READ
+	 * and FMODE_WRITE.
+	 */
+	fmode_t mode;
+
+	/* a list of devices used by this table */
+	struct list_head devices;
+
+	/* events get handed up using this callback */
+	void (*event_fn)(void *);
+	void *event_context;
+
+	struct dm_md_mempools *mempools;
+
+	struct list_head target_callbacks;
+};
+
+/*
+ * 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;
+}
+
+void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size)
+{
+	unsigned long size;
+	void *addr;
+
+	/*
+	 * Check that we're not going to overflow.
+	 */
+	if (nmemb > (ULONG_MAX / elem_size))
+		return NULL;
+
+	size = nmemb * elem_size;
+	addr = vzalloc(size);
+
+	return addr;
+}
+EXPORT_SYMBOL(dm_vcalloc);
+
+/*
+ * 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.
+	 * Append an empty entry to catch sectors beyond the end of
+	 * the device.
+	 */
+	n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
+					  sizeof(sector_t));
+	if (!n_highs)
+		return -ENOMEM;
+
+	n_targets = (struct dm_target *) (n_highs + num);
+
+	memset(n_highs, -1, sizeof(*n_highs) * num);
+	vfree(t->highs);
+
+	t->num_allocated = num;
+	t->highs = n_highs;
+	t->targets = n_targets;
+
+	return 0;
+}
+
+int dm_table_create(struct dm_table **result, fmode_t mode,
+		    unsigned num_targets, struct mapped_device *md)
+{
+	struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
+
+	if (!t)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&t->devices);
+	INIT_LIST_HEAD(&t->target_callbacks);
+
+	if (!num_targets)
+		num_targets = KEYS_PER_NODE;
+
+	num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
+
+	if (!num_targets) {
+		kfree(t);
+		return -ENOMEM;
+	}
+
+	if (alloc_targets(t, num_targets)) {
+		kfree(t);
+		return -ENOMEM;
+	}
+
+	t->mode = mode;
+	t->md = md;
+	*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);
+	}
+}
+
+void dm_table_destroy(struct dm_table *t)
+{
+	unsigned int i;
+
+	if (!t)
+		return;
+
+	/* free the indexes */
+	if (t->depth >= 2)
+		vfree(t->index[t->depth - 2]);
+
+	/* free the targets */
+	for (i = 0; i < t->num_targets; i++) {
+		struct dm_target *tgt = t->targets + i;
+
+		if (tgt->type->dtr)
+			tgt->type->dtr(tgt);
+
+		dm_put_target_type(tgt->type);
+	}
+
+	vfree(t->highs);
+
+	/* free the device list */
+	free_devices(&t->devices, t->md);
+
+	dm_free_md_mempools(t->mempools);
+
+	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 request_queue *q;
+	struct queue_limits *limits = data;
+	struct block_device *bdev = dev->bdev;
+	sector_t dev_size =
+		i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
+	unsigned short logical_block_size_sectors =
+		limits->logical_block_size >> SECTOR_SHIFT;
+	char b[BDEVNAME_SIZE];
+
+	/*
+	 * Some devices exist without request functions,
+	 * such as loop devices not yet bound to backing files.
+	 * Forbid the use of such devices.
+	 */
+	q = bdev_get_queue(bdev);
+	if (!q || !q->make_request_fn) {
+		DMWARN("%s: %s is not yet initialised: "
+		       "start=%llu, len=%llu, dev_size=%llu",
+		       dm_device_name(ti->table->md), bdevname(bdev, b),
+		       (unsigned long long)start,
+		       (unsigned long long)len,
+		       (unsigned long long)dev_size);
+		return 1;
+	}
+
+	if (!dev_size)
+		return 0;
+
+	if ((start >= dev_size) || (start + len > dev_size)) {
+		DMWARN("%s: %s too small for target: "
+		       "start=%llu, len=%llu, dev_size=%llu",
+		       dm_device_name(ti->table->md), bdevname(bdev, b),
+		       (unsigned long long)start,
+		       (unsigned long long)len,
+		       (unsigned long long)dev_size);
+		return 1;
+	}
+
+	if (logical_block_size_sectors <= 1)
+		return 0;
+
+	if (start & (logical_block_size_sectors - 1)) {
+		DMWARN("%s: start=%llu not aligned to h/w "
+		       "logical block size %u of %s",
+		       dm_device_name(ti->table->md),
+		       (unsigned long long)start,
+		       limits->logical_block_size, bdevname(bdev, b));
+		return 1;
+	}
+
+	if (len & (logical_block_size_sectors - 1)) {
+		DMWARN("%s: len=%llu not aligned to h/w "
+		       "logical block size %u of %s",
+		       dm_device_name(ti->table->md),
+		       (unsigned long long)len,
+		       limits->logical_block_size, bdevname(bdev, b));
+		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 inside dm_table_any_congested().
+ */
+static int upgrade_mode(struct dm_dev_internal *dd, fmode_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;
+}
+
+/*
+ * 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, fmode_t mode,
+		  struct dm_dev **result)
+{
+	int r;
+	dev_t uninitialized_var(dev);
+	struct dm_dev_internal *dd;
+	struct dm_table *t = ti->table;
+	struct block_device *bdev;
+
+	BUG_ON(!t);
+
+	/* convert the path to a device */
+	bdev = lookup_bdev(path);
+	if (IS_ERR(bdev)) {
+		dev = name_to_dev_t(path);
+		if (!dev)
+			return -ENODEV;
+	} else {
+		dev = bdev->bd_dev;
+		bdput(bdev);
+	}
+
+	dd = find_device(&t->devices, dev);
+	if (!dd) {
+		dd = kmalloc(sizeof(*dd), GFP_KERNEL);
+		if (!dd)
+			return -ENOMEM;
+
+		if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
+			kfree(dd);
+			return r;
+		}
+
+		atomic_set(&dd->count, 0);
+		list_add(&dd->list, &t->devices);
+
+	} else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
+		r = upgrade_mode(dd, mode, t->md);
+		if (r)
+			return r;
+	}
+	atomic_inc(&dd->count);
+
+	*result = dd->dm_dev;
+	return 0;
+}
+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);
+	char b[BDEVNAME_SIZE];
+
+	if (unlikely(!q)) {
+		DMWARN("%s: Cannot set limits for nonexistent device %s",
+		       dm_device_name(ti->table->md), bdevname(bdev, b));
+		return 0;
+	}
+
+	if (bdev_stack_limits(limits, bdev, start) < 0)
+		DMWARN("%s: adding target device %s caused an alignment inconsistency: "
+		       "physical_block_size=%u, logical_block_size=%u, "
+		       "alignment_offset=%u, start=%llu",
+		       dm_device_name(ti->table->md), bdevname(bdev, b),
+		       q->limits.physical_block_size,
+		       q->limits.logical_block_size,
+		       q->limits.alignment_offset,
+		       (unsigned long long) start << SECTOR_SHIFT);
+
+	/*
+	 * Check if merge fn is supported.
+	 * If not we'll force DM to use PAGE_SIZE or
+	 * smaller I/O, just to be safe.
+	 */
+	if (dm_queue_merge_is_compulsory(q) && !ti->type->merge)
+		blk_limits_max_hw_sectors(limits,
+					  (unsigned int) (PAGE_SIZE >> 9));
+	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 list_head *devices = &ti->table->devices;
+	struct dm_dev_internal *dd;
+
+	list_for_each_entry(dd, devices, list) {
+		if (dd->dm_dev == d) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found) {
+		DMWARN("%s: device %s not in table devices list",
+		       dm_device_name(ti->table->md), d->name);
+		return;
+	}
+	if (atomic_dec_and_test(&dd->count)) {
+		dm_put_table_device(ti->table->md, d);
+		list_del(&dd->list);
+		kfree(dd);
+	}
+}
+EXPORT_SYMBOL(dm_put_device);
+
+/*
+ * Checks to see if the target joins onto the end of the table.
+ */
+static int adjoin(struct dm_table *table, struct dm_target *ti)
+{
+	struct dm_target *prev;
+
+	if (!table->num_targets)
+		return !ti->begin;
+
+	prev = &table->targets[table->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 *array_size, char **old_argv)
+{
+	char **argv;
+	unsigned new_size;
+	gfp_t gfp;
+
+	if (*array_size) {
+		new_size = *array_size * 2;
+		gfp = GFP_KERNEL;
+	} else {
+		new_size = 8;
+		gfp = GFP_NOIO;
+	}
+	argv = kmalloc(new_size * sizeof(*argv), gfp);
+	if (argv) {
+		memcpy(argv, old_argv, *array_size * sizeof(*argv));
+		*array_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 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;
+}
+
+/*
+ * 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 *table,
+						 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 *uninitialized_var(ti);
+	struct queue_limits ti_limits;
+	unsigned i = 0;
+
+	/*
+	 * Check each entry in the table in turn.
+	 */
+	while (i < dm_table_get_num_targets(table)) {
+		ti = dm_table_get_target(table, i++);
+
+		blk_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) {
+		DMWARN("%s: table line %u (start sect %llu len %llu) "
+		       "not aligned to h/w logical block size %u",
+		       dm_device_name(table->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 *tgt;
+
+	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);
+
+	tgt = t->targets + t->num_targets;
+	memset(tgt, 0, sizeof(*tgt));
+
+	if (!len) {
+		DMERR("%s: zero-length target", dm_device_name(t->md));
+		return -EINVAL;
+	}
+
+	tgt->type = dm_get_target_type(type);
+	if (!tgt->type) {
+		DMERR("%s: %s: unknown target type", dm_device_name(t->md),
+		      type);
+		return -EINVAL;
+	}
+
+	if (dm_target_needs_singleton(tgt->type)) {
+		if (t->num_targets) {
+			DMERR("%s: target type %s must appear alone in table",
+			      dm_device_name(t->md), type);
+			return -EINVAL;
+		}
+		t->singleton = 1;
+	}
+
+	if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
+		DMERR("%s: target type %s may not be included in read-only tables",
+		      dm_device_name(t->md), type);
+		return -EINVAL;
+	}
+
+	if (t->immutable_target_type) {
+		if (t->immutable_target_type != tgt->type) {
+			DMERR("%s: immutable target type %s cannot be mixed with other target types",
+			      dm_device_name(t->md), t->immutable_target_type->name);
+			return -EINVAL;
+		}
+	} else if (dm_target_is_immutable(tgt->type)) {
+		if (t->num_targets) {
+			DMERR("%s: immutable target type %s cannot be mixed with other target types",
+			      dm_device_name(t->md), tgt->type->name);
+			return -EINVAL;
+		}
+		t->immutable_target_type = tgt->type;
+	}
+
+	tgt->table = t;
+	tgt->begin = start;
+	tgt->len = len;
+	tgt->error = "Unknown error";
+
+	/*
+	 * Does this target adjoin the previous one ?
+	 */
+	if (!adjoin(t, tgt)) {
+		tgt->error = "Gap in table";
+		r = -EINVAL;
+		goto bad;
+	}
+
+	r = dm_split_args(&argc, &argv, params);
+	if (r) {
+		tgt->error = "couldn't split parameters (insufficient memory)";
+		goto bad;
+	}
+
+	r = tgt->type->ctr(tgt, argc, argv);
+	kfree(argv);
+	if (r)
+		goto bad;
+
+	t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
+
+	if (!tgt->num_discard_bios && tgt->discards_supported)
+		DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
+		       dm_device_name(t->md), type);
+
+	return 0;
+
+ bad:
+	DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
+	dm_put_target_type(tgt->type);
+	return r;
+}
+
+/*
+ * Target argument parsing helpers.
+ */
+static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
+			     unsigned *value, char **error, unsigned 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(struct dm_arg *arg, struct dm_arg_set *arg_set,
+		unsigned *value, char **error)
+{
+	return validate_next_arg(arg, arg_set, value, error, 0);
+}
+EXPORT_SYMBOL(dm_read_arg);
+
+int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
+		      unsigned *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 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_request_based(unsigned table_type)
+{
+	return (table_type == DM_TYPE_REQUEST_BASED ||
+		table_type == DM_TYPE_MQ_REQUEST_BASED);
+}
+
+static int dm_table_set_type(struct dm_table *t)
+{
+	unsigned i;
+	unsigned bio_based = 0, request_based = 0, hybrid = 0;
+	bool use_blk_mq = false;
+	struct dm_target *tgt;
+	struct dm_dev_internal *dd;
+	struct list_head *devices;
+	unsigned live_md_type = dm_get_md_type(t->md);
+
+	for (i = 0; i < t->num_targets; i++) {
+		tgt = t->targets + i;
+		if (dm_target_hybrid(tgt))
+			hybrid = 1;
+		else if (dm_target_request_based(tgt))
+			request_based = 1;
+		else
+			bio_based = 1;
+
+		if (bio_based && request_based) {
+			DMWARN("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) {
+		/* We must use this table as bio-based */
+		t->type = DM_TYPE_BIO_BASED;
+		return 0;
+	}
+
+	BUG_ON(!request_based); /* No targets in this table */
+
+	/*
+	 * 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) {
+		DMWARN("Request-based dm doesn't support multiple targets yet");
+		return -EINVAL;
+	}
+
+	/* Non-request-stackable devices can't be used for request-based dm */
+	devices = dm_table_get_devices(t);
+	list_for_each_entry(dd, devices, list) {
+		struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
+
+		if (!blk_queue_stackable(q)) {
+			DMERR("table load rejected: including"
+			      " non-request-stackable devices");
+			return -EINVAL;
+		}
+
+		if (q->mq_ops)
+			use_blk_mq = true;
+	}
+
+	if (use_blk_mq) {
+		/* verify _all_ devices in the table are blk-mq devices */
+		list_for_each_entry(dd, devices, list)
+			if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
+				DMERR("table load rejected: not all devices"
+				      " are blk-mq request-stackable");
+				return -EINVAL;
+			}
+		t->type = DM_TYPE_MQ_REQUEST_BASED;
+
+	} else if (list_empty(devices) && __table_type_request_based(live_md_type)) {
+		/* inherit live MD type */
+		t->type = live_md_type;
+
+	} else
+		t->type = DM_TYPE_REQUEST_BASED;
+
+	return 0;
+}
+
+unsigned 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;
+}
+
+bool dm_table_request_based(struct dm_table *t)
+{
+	return __table_type_request_based(dm_table_get_type(t));
+}
+
+bool dm_table_mq_request_based(struct dm_table *t)
+{
+	return dm_table_get_type(t) == DM_TYPE_MQ_REQUEST_BASED;
+}
+
+static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
+{
+	unsigned type = dm_table_get_type(t);
+	unsigned per_bio_data_size = 0;
+	struct dm_target *tgt;
+	unsigned i;
+
+	if (unlikely(type == DM_TYPE_NONE)) {
+		DMWARN("no table type is set, can't allocate mempools");
+		return -EINVAL;
+	}
+
+	if (type == DM_TYPE_BIO_BASED)
+		for (i = 0; i < t->num_targets; i++) {
+			tgt = t->targets + i;
+			per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
+		}
+
+	t->mempools = dm_alloc_md_mempools(md, type, t->integrity_supported, per_bio_data_size);
+	if (!t->mempools)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void dm_table_free_md_mempools(struct dm_table *t)
+{
+	dm_free_md_mempools(t->mempools);
+	t->mempools = NULL;
+}
+
+struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
+{
+	return t->mempools;
+}
+
+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 = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
+	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;
+}
+
+/*
+ * Get a disk whose integrity profile reflects the table's profile.
+ * If %match_all is true, all devices' profiles must match.
+ * If %match_all is false, all devices must at least have an
+ * allocated integrity profile; but uninitialized is ok.
+ * Returns NULL if integrity support was inconsistent or unavailable.
+ */
+static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t,
+						    bool match_all)
+{
+	struct list_head *devices = dm_table_get_devices(t);
+	struct dm_dev_internal *dd = NULL;
+	struct gendisk *prev_disk = NULL, *template_disk = NULL;
+
+	list_for_each_entry(dd, devices, list) {
+		template_disk = dd->dm_dev->bdev->bd_disk;
+		if (!blk_get_integrity(template_disk))
+			goto no_integrity;
+		if (!match_all && !blk_integrity_is_initialized(template_disk))
+			continue; /* skip uninitialized profiles */
+		else if (prev_disk &&
+			 blk_integrity_compare(prev_disk, template_disk) < 0)
+			goto no_integrity;
+		prev_disk = template_disk;
+	}
+
+	return template_disk;
+
+no_integrity:
+	if (prev_disk)
+		DMWARN("%s: integrity not set: %s and %s profile mismatch",
+		       dm_device_name(t->md),
+		       prev_disk->disk_name,
+		       template_disk->disk_name);
+	return NULL;
+}
+
+/*
+ * Register the mapped device for blk_integrity support if
+ * the underlying devices have an integrity profile.  But all devices
+ * may not have matching profiles (checking all devices isn't reliable
+ * during table load because this table may use other DM device(s) which
+ * must be resumed before they will have an initialized integity profile).
+ * Stacked DM devices force a 2 stage integrity profile validation:
+ * 1 - during load, validate all initialized integrity profiles match
+ * 2 - during resume, validate all integrity profiles match
+ */
+static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device *md)
+{
+	struct gendisk *template_disk = NULL;
+
+	template_disk = dm_table_get_integrity_disk(t, false);
+	if (!template_disk)
+		return 0;
+
+	if (!blk_integrity_is_initialized(dm_disk(md))) {
+		t->integrity_supported = 1;
+		return blk_integrity_register(dm_disk(md), NULL);
+	}
+
+	/*
+	 * If DM device already has an initalized integrity
+	 * profile the new profile should not conflict.
+	 */
+	if (blk_integrity_is_initialized(template_disk) &&
+	    blk_integrity_compare(dm_disk(md), template_disk) < 0) {
+		DMWARN("%s: conflict with existing integrity profile: "
+		       "%s profile mismatch",
+		       dm_device_name(t->md),
+		       template_disk->disk_name);
+		return 1;
+	}
+
+	/* Preserve existing initialized integrity profile */
+	t->integrity_supported = 1;
+	return 0;
+}
+
+/*
+ * 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_set_type(t);
+	if (r) {
+		DMERR("unable to set table type");
+		return r;
+	}
+
+	r = dm_table_build_index(t);
+	if (r) {
+		DMERR("unable to build btrees");
+		return r;
+	}
+
+	r = dm_table_prealloc_integrity(t, t->md);
+	if (r) {
+		DMERR("could not register integrity 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)
+{
+	/*
+	 * You can no longer call dm_table_event() from interrupt
+	 * context, use a bottom half instead.
+	 */
+	BUG_ON(in_interrupt());
+
+	mutex_lock(&_event_lock);
+	if (t->event_fn)
+		t->event_fn(t->event_context);
+	mutex_unlock(&_event_lock);
+}
+EXPORT_SYMBOL(dm_table_event);
+
+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);
+
+struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
+{
+	if (index >= t->num_targets)
+		return NULL;
+
+	return t->targets + index;
+}
+
+/*
+ * Search the btree for the correct target.
+ *
+ * Caller should check returned pointer with dm_target_is_valid()
+ * 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;
+
+	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];
+}
+
+static int count_device(struct dm_target *ti, struct dm_dev *dev,
+			sector_t start, sector_t len, void *data)
+{
+	unsigned *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 *table)
+{
+	struct dm_target *uninitialized_var(ti);
+	unsigned i = 0, num_devices = 0;
+
+	while (i < dm_table_get_num_targets(table)) {
+		ti = dm_table_get_target(table, i++);
+
+		if (!ti->type->iterate_devices)
+			return false;
+
+		ti->type->iterate_devices(ti, count_device, &num_devices);
+		if (num_devices)
+			return false;
+	}
+
+	return true;
+}
+
+/*
+ * Establish the new table's queue_limits and validate them.
+ */
+int dm_calculate_queue_limits(struct dm_table *table,
+			      struct queue_limits *limits)
+{
+	struct dm_target *uninitialized_var(ti);
+	struct queue_limits ti_limits;
+	unsigned i = 0;
+
+	blk_set_stacking_limits(limits);
+
+	while (i < dm_table_get_num_targets(table)) {
+		blk_set_stacking_limits(&ti_limits);
+
+		ti = dm_table_get_target(table, i++);
+
+		if (!ti->type->iterate_devices)
+			goto combine_limits;
+
+		/*
+		 * Combine queue limits of all the devices this target uses.
+		 */
+		ti->type->iterate_devices(ti, dm_set_device_limits,
+					  &ti_limits);
+
+		/* 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(table->md),
+			       (unsigned long long) ti->begin,
+			       (unsigned long long) ti->len);
+	}
+
+	return validate_hardware_logical_block_alignment(table, limits);
+}
+
+/*
+ * Set the integrity profile for this device if all devices used have
+ * matching profiles.  We're quite deep in the resume path but still
+ * don't know if all devices (particularly DM devices this device
+ * may be stacked on) have matching profiles.  Even if the profiles
+ * don't match we have no way to fail (to resume) at this point.
+ */
+static void dm_table_set_integrity(struct dm_table *t)
+{
+	struct gendisk *template_disk = NULL;
+
+	if (!blk_get_integrity(dm_disk(t->md)))
+		return;
+
+	template_disk = dm_table_get_integrity_disk(t, true);
+	if (template_disk)
+		blk_integrity_register(dm_disk(t->md),
+				       blk_get_integrity(template_disk));
+	else if (blk_integrity_is_initialized(dm_disk(t->md)))
+		DMWARN("%s: device no longer has a valid integrity profile",
+		       dm_device_name(t->md));
+	else
+		DMWARN("%s: unable to establish an integrity profile",
+		       dm_device_name(t->md));
+}
+
+static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
+				sector_t start, sector_t len, void *data)
+{
+	unsigned flush = (*(unsigned *)data);
+	struct request_queue *q = bdev_get_queue(dev->bdev);
+
+	return q && (q->flush_flags & flush);
+}
+
+static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
+{
+	struct dm_target *ti;
+	unsigned i = 0;
+
+	/*
+	 * Require at least one underlying device to support flushes.
+	 * t->devices includes internal dm devices such as mirror logs
+	 * so we need to use iterate_devices here, which targets
+	 * supporting flushes must provide.
+	 */
+	while (i < dm_table_get_num_targets(t)) {
+		ti = dm_table_get_target(t, i++);
+
+		if (!ti->num_flush_bios)
+			continue;
+
+		if (ti->flush_supported)
+			return true;
+
+		if (ti->type->iterate_devices &&
+		    ti->type->iterate_devices(ti, device_flush_capable, &flush))
+			return true;
+	}
+
+	return false;
+}
+
+static bool dm_table_discard_zeroes_data(struct dm_table *t)
+{
+	struct dm_target *ti;
+	unsigned i = 0;
+
+	/* Ensure that all targets supports discard_zeroes_data. */
+	while (i < dm_table_get_num_targets(t)) {
+		ti = dm_table_get_target(t, i++);
+
+		if (ti->discard_zeroes_data_unsupported)
+			return false;
+	}
+
+	return true;
+}
+
+static int device_is_nonrot(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 && blk_queue_nonrot(q);
+}
+
+static int device_is_not_random(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 && !blk_queue_add_random(q);
+}
+
+static int queue_supports_sg_merge(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 && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
+}
+
+static int queue_supports_sg_gaps(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 && !test_bit(QUEUE_FLAG_SG_GAPS, &q->queue_flags);
+}
+
+static bool dm_table_all_devices_attribute(struct dm_table *t,
+					   iterate_devices_callout_fn func)
+{
+	struct dm_target *ti;
+	unsigned i = 0;
+
+	while (i < dm_table_get_num_targets(t)) {
+		ti = dm_table_get_target(t, i++);
+
+		if (!ti->type->iterate_devices ||
+		    !ti->type->iterate_devices(ti, func, NULL))
+			return false;
+	}
+
+	return true;
+}
+
+static int device_not_write_same_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 && !q->limits.max_write_same_sectors;
+}
+
+static bool dm_table_supports_write_same(struct dm_table *t)
+{
+	struct dm_target *ti;
+	unsigned i = 0;
+
+	while (i < dm_table_get_num_targets(t)) {
+		ti = dm_table_get_target(t, i++);
+
+		if (!ti->num_write_same_bios)
+			return false;
+
+		if (!ti->type->iterate_devices ||
+		    ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
+			return false;
+	}
+
+	return true;
+}
+
+static int device_discard_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 && blk_queue_discard(q);
+}
+
+static bool dm_table_supports_discards(struct dm_table *t)
+{
+	struct dm_target *ti;
+	unsigned i = 0;
+
+	/*
+	 * Unless any target used by the table set discards_supported,
+	 * require at least one underlying device to support discards.
+	 * t->devices includes internal dm devices such as mirror logs
+	 * so we need to use iterate_devices here, which targets
+	 * supporting discard selectively must provide.
+	 */
+	while (i < dm_table_get_num_targets(t)) {
+		ti = dm_table_get_target(t, i++);
+
+		if (!ti->num_discard_bios)
+			continue;
+
+		if (ti->discards_supported)
+			return true;
+
+		if (ti->type->iterate_devices &&
+		    ti->type->iterate_devices(ti, device_discard_capable, NULL))
+			return true;
+	}
+
+	return false;
+}
+
+void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
+			       struct queue_limits *limits)
+{
+	unsigned flush = 0;
+
+	/*
+	 * Copy table's limits to the DM device's request_queue
+	 */
+	q->limits = *limits;
+
+	if (!dm_table_supports_discards(t))
+		queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
+	else
+		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
+
+	if (dm_table_supports_flush(t, REQ_FLUSH)) {
+		flush |= REQ_FLUSH;
+		if (dm_table_supports_flush(t, REQ_FUA))
+			flush |= REQ_FUA;
+	}
+	blk_queue_flush(q, flush);
+
+	if (!dm_table_discard_zeroes_data(t))
+		q->limits.discard_zeroes_data = 0;
+
+	/* Ensure that all underlying devices are non-rotational. */
+	if (dm_table_all_devices_attribute(t, device_is_nonrot))
+		queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
+	else
+		queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
+
+	if (!dm_table_supports_write_same(t))
+		q->limits.max_write_same_sectors = 0;
+
+	if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))
+		queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
+	else
+		queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
+
+	if (dm_table_all_devices_attribute(t, queue_supports_sg_gaps))
+		queue_flag_clear_unlocked(QUEUE_FLAG_SG_GAPS, q);
+	else
+		queue_flag_set_unlocked(QUEUE_FLAG_SG_GAPS, q);
+
+	dm_table_set_integrity(t);
+
+	/*
+	 * Determine whether or not this queue's I/O timings contribute
+	 * to the entropy pool, Only request-based targets use this.
+	 * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
+	 * have it set.
+	 */
+	if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
+		queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
+
+	/*
+	 * QUEUE_FLAG_STACKABLE must be set after all queue settings are
+	 * visible to other CPUs because, once the flag is set, incoming bios
+	 * are processed by request-based dm, which refers to the queue
+	 * settings.
+	 * Until the flag set, bios are passed to bio-based dm and queued to
+	 * md->deferred where queue settings are not needed yet.
+	 * Those bios are passed to request-based dm at the resume time.
+	 */
+	smp_mb();
+	if (dm_table_request_based(t))
+		queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
+}
+
+unsigned int dm_table_get_num_targets(struct dm_table *t)
+{
+	return t->num_targets;
+}
+
+struct list_head *dm_table_get_devices(struct dm_table *t)
+{
+	return &t->devices;
+}
+
+fmode_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)
+{
+	int i = t->num_targets;
+	struct dm_target *ti = t->targets;
+
+	while (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;
+		}
+		ti++;
+	}
+}
+
+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)
+{
+	int i, r = 0;
+
+	for (i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = t->targets + 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 = t->targets + i;
+
+		if (ti->type->resume)
+			ti->type->resume(ti);
+	}
+
+	return 0;
+}
+
+void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
+{
+	list_add(&cb->list, &t->target_callbacks);
+}
+EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
+
+int dm_table_any_congested(struct dm_table *t, int bdi_bits)
+{
+	struct dm_dev_internal *dd;
+	struct list_head *devices = dm_table_get_devices(t);
+	struct dm_target_callbacks *cb;
+	int r = 0;
+
+	list_for_each_entry(dd, devices, list) {
+		struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
+		char b[BDEVNAME_SIZE];
+
+		if (likely(q))
+			r |= bdi_congested(&q->backing_dev_info, bdi_bits);
+		else
+			DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
+				     dm_device_name(t->md),
+				     bdevname(dd->dm_dev->bdev, b));
+	}
+
+	list_for_each_entry(cb, &t->target_callbacks, list)
+		if (cb->congested_fn)
+			r |= cb->congested_fn(cb, bdi_bits);
+
+	return r;
+}
+
+struct mapped_device *dm_table_get_md(struct dm_table *t)
+{
+	return t->md;
+}
+EXPORT_SYMBOL(dm_table_get_md);
+
+void dm_table_run_md_queue_async(struct dm_table *t)
+{
+	struct mapped_device *md;
+	struct request_queue *queue;
+	unsigned long flags;
+
+	if (!dm_table_request_based(t))
+		return;
+
+	md = dm_table_get_md(t);
+	queue = dm_get_md_queue(md);
+	if (queue) {
+		if (queue->mq_ops)
+			blk_mq_run_hw_queues(queue, true);
+		else {
+			spin_lock_irqsave(queue->queue_lock, flags);
+			blk_run_queue_async(queue);
+			spin_unlock_irqrestore(queue->queue_lock, flags);
+		}
+	}
+}
+EXPORT_SYMBOL(dm_table_run_md_queue_async);
+