Support an arbitrary number of target parameters.  [Alasdair Kergon]
--- diff/drivers/md/dm-table.c	2003-08-15 14:52:14.000000000 +0100
+++ source/drivers/md/dm-table.c	2003-08-20 16:28:37.000000000 +0100
@@ -441,12 +441,36 @@
 }
 
 /*
+ * Used to dynamically allocate the arg array.
+ */
+static char **realloc_argv(unsigned *array_size, char **old_argv)
+{
+	char **argv;
+	unsigned new_size;
+
+	new_size = *array_size ? *array_size * 2 : 64;
+	argv = kmalloc(new_size * sizeof(*argv), GFP_KERNEL);
+	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.
  */
-static int split_args(int max, int *argc, char **argv, char *input)
+static int split_args(int *argc, char ***argvp, char *input)
 {
-	char *start, *end = input, *out;
+	char *start, *end = input, *out, **argv = NULL;
+	unsigned array_size = 0;
+
 	*argc = 0;
+	argv = realloc_argv(&array_size, argv);
+	if (!argv)
+		return -ENOMEM;
 
 	while (1) {
 		start = end;
@@ -475,8 +499,11 @@
 		}
 
 		/* have we already filled the array ? */
-		if ((*argc + 1) > max)
-			return -EINVAL;
+		if ((*argc + 1) > array_size) {
+			argv = realloc_argv(&array_size, argv);
+			if (!argv)
+				return -ENOMEM;
+		}
 
 		/* we know this is whitespace */
 		if (*end)
@@ -488,6 +515,7 @@
 		(*argc)++;
 	}
 
+	*argvp = argv;
 	return 0;
 }
 
@@ -495,7 +523,7 @@
 			sector_t start, sector_t len, char *params)
 {
 	int r = -EINVAL, argc;
-	char *argv[32];
+	char **argv;
 	struct dm_target *tgt;
 
 	if ((r = check_space(t)))
@@ -524,13 +552,14 @@
 		goto bad;
 	}
 
-	r = split_args(ARRAY_SIZE(argv), &argc, argv, params);
+	r = split_args(&argc, &argv, params);
 	if (r) {
-		tgt->error = "couldn't split parameters";
+		tgt->error = "couldn't split parameters (insufficient memory)";
 		goto bad;
 	}
 
 	r = tgt->type->ctr(tgt, argc, argv);
+	kfree(argv);
 	if (r)
 		goto bad;
 
--- diff/drivers/md/dm-table.c.orig	1970-01-01 01:00:00.000000000 +0100
+++ source/drivers/md/dm-table.c.orig	2003-08-15 14:52:14.000000000 +0100
@@ -0,0 +1,687 @@
+/*
+ * Copyright (C) 2001 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/blkdev.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <asm/atomic.h>
+
+#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 {
+	atomic_t holders;
+
+	/* 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;
+
+	/*
+	 * Indicates the rw permissions for the new logical
+	 * device.  This should be a combination of FMODE_READ
+	 * and FMODE_WRITE.
+	 */
+	int 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;
+};
+
+/*
+ * Similar to ceiling(log_size(n))
+ */
+static unsigned int int_log(unsigned long n, unsigned long 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;
+	int n = t->num_targets;
+
+	/*
+	 * Allocate both the target array and offset array at once.
+	 */
+	n_highs = (sector_t *) vcalloc(sizeof(struct dm_target) +
+				       sizeof(sector_t), num);
+	if (!n_highs)
+		return -ENOMEM;
+
+	n_targets = (struct dm_target *) (n_highs + num);
+
+	if (n) {
+		memcpy(n_highs, t->highs, sizeof(*n_highs) * n);
+		memcpy(n_targets, t->targets, sizeof(*n_targets) * n);
+	}
+
+	memset(n_highs + n, -1, sizeof(*n_highs) * (num - n));
+	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, int mode)
+{
+	struct dm_table *t = kmalloc(sizeof(*t), GFP_NOIO);
+
+	if (!t)
+		return -ENOMEM;
+
+	memset(t, 0, sizeof(*t));
+	INIT_LIST_HEAD(&t->devices);
+	atomic_set(&t->holders, 1);
+
+	/* allocate a single nodes worth of targets to begin with */
+	if (alloc_targets(t, KEYS_PER_NODE)) {
+		kfree(t);
+		t = NULL;
+		return -ENOMEM;
+	}
+
+	t->mode = mode;
+	*result = t;
+	return 0;
+}
+
+static void free_devices(struct list_head *devices)
+{
+	struct list_head *tmp, *next;
+
+	for (tmp = devices->next; tmp != devices; tmp = next) {
+		struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
+		next = tmp->next;
+		kfree(dd);
+	}
+}
+
+void table_destroy(struct dm_table *t)
+{
+	unsigned int i;
+
+	/* free the indexes (see dm_table_complete) */
+	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 */
+	if (t->devices.next != &t->devices) {
+		DMWARN("devices still present during destroy: "
+		       "dm_table_remove_device calls missing");
+
+		free_devices(&t->devices);
+	}
+
+	kfree(t);
+}
+
+void dm_table_get(struct dm_table *t)
+{
+	atomic_inc(&t->holders);
+}
+
+void dm_table_put(struct dm_table *t)
+{
+	if (atomic_dec_and_test(&t->holders))
+		table_destroy(t);
+}
+
+/*
+ * Checks to see if we need to extend highs or targets.
+ */
+static inline int check_space(struct dm_table *t)
+{
+	if (t->num_targets >= t->num_allocated)
+		return alloc_targets(t, t->num_allocated * 2);
+
+	return 0;
+}
+
+/*
+ * Convert a device path to a dev_t.
+ */
+static int lookup_device(const char *path, kdev_t *dev)
+{
+	int r;
+	struct nameidata nd;
+	struct inode *inode;
+
+	if (!path_init(path, LOOKUP_FOLLOW, &nd))
+		return 0;
+
+	if ((r = path_walk(path, &nd)))
+		goto out;
+
+	inode = nd.dentry->d_inode;
+	if (!inode) {
+		r = -ENOENT;
+		goto out;
+	}
+
+	if (!S_ISBLK(inode->i_mode)) {
+		r = -ENOTBLK;
+		goto out;
+	}
+
+	*dev = inode->i_rdev;
+
+      out:
+	path_release(&nd);
+	return r;
+}
+
+/*
+ * See if we've already got a device in the list.
+ */
+static struct dm_dev *find_device(struct list_head *l, kdev_t dev)
+{
+	struct list_head *tmp;
+
+	list_for_each(tmp, l) {
+		struct dm_dev *dd = list_entry(tmp, struct dm_dev, list);
+		if (kdev_same(dd->dev, dev))
+			return dd;
+	}
+
+	return NULL;
+}
+
+/*
+ * Open a device so we can use it as a map destination.
+ */
+static int open_dev(struct dm_dev *dd)
+{
+	if (dd->bdev)
+		BUG();
+
+	dd->bdev = bdget(kdev_t_to_nr(dd->dev));
+	if (!dd->bdev)
+		return -ENOMEM;
+
+	return blkdev_get(dd->bdev, dd->mode, 0, BDEV_RAW);
+}
+
+/*
+ * Close a device that we've been using.
+ */
+static void close_dev(struct dm_dev *dd)
+{
+	if (!dd->bdev)
+		return;
+
+	blkdev_put(dd->bdev, BDEV_RAW);
+	dd->bdev = NULL;
+}
+
+/*
+ * If possible (ie. blk_size[major] is set), this checks an area
+ * of a destination device is valid.
+ */
+static int check_device_area(kdev_t dev, sector_t start, sector_t len)
+{
+	int *sizes;
+	sector_t dev_size;
+
+	if (!(sizes = blk_size[major(dev)]) || !(dev_size = sizes[minor(dev)]))
+		/* we don't know the device details,
+		 * so give the benefit of the doubt */
+		return 1;
+
+	/* convert to 512-byte sectors */
+	dev_size <<= 1;
+
+	return ((start < dev_size) && (len <= (dev_size - start)));
+}
+
+/*
+ * 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.
+ */
+static int upgrade_mode(struct dm_dev *dd, int new_mode)
+{
+	int r;
+	struct dm_dev dd_copy;
+
+	memcpy(&dd_copy, dd, sizeof(dd_copy));
+
+	dd->mode |= new_mode;
+	dd->bdev = NULL;
+	r = open_dev(dd);
+	if (!r)
+		close_dev(&dd_copy);
+	else
+		memcpy(dd, &dd_copy, sizeof(dd_copy));
+
+	return r;
+}
+
+/*
+ * 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, sector_t start,
+		  sector_t len, int mode, struct dm_dev **result)
+{
+	int r;
+	kdev_t dev;
+	struct dm_dev *dd;
+	unsigned major, minor;
+	struct dm_table *t = ti->table;
+
+	if (!t)
+		BUG();
+
+	if (sscanf(path, "%u:%u", &major, &minor) == 2) {
+		/* Extract the major/minor numbers */
+		dev = mk_kdev(major, minor);
+	} else {
+		/* convert the path to a device */
+		if ((r = lookup_device(path, &dev)))
+			return r;
+	}
+
+	dd = find_device(&t->devices, dev);
+	if (!dd) {
+		dd = kmalloc(sizeof(*dd), GFP_KERNEL);
+		if (!dd)
+			return -ENOMEM;
+
+		dd->dev = dev;
+		dd->mode = mode;
+		dd->bdev = NULL;
+
+		if ((r = open_dev(dd))) {
+			kfree(dd);
+			return r;
+		}
+
+		atomic_set(&dd->count, 0);
+		list_add(&dd->list, &t->devices);
+
+	} else if (dd->mode != (mode | dd->mode)) {
+		r = upgrade_mode(dd, mode);
+		if (r)
+			return r;
+	}
+	atomic_inc(&dd->count);
+
+	if (!check_device_area(dd->dev, start, len)) {
+		DMWARN("device %s too small for target", path);
+		dm_put_device(ti, dd);
+		return -EINVAL;
+	}
+
+	*result = dd;
+
+	return 0;
+}
+
+/*
+ * Decrement a devices use count and remove it if neccessary.
+ */
+void dm_put_device(struct dm_target *ti, struct dm_dev *dd)
+{
+	if (atomic_dec_and_test(&dd->count)) {
+		close_dev(dd);
+		list_del(&dd->list);
+		kfree(dd);
+	}
+}
+
+/*
+ * 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));
+}
+
+/*
+ * Destructively splits up the argument list to pass to ctr.
+ */
+static int split_args(int max, int *argc, char **argv, char *input)
+{
+	char *start, *end = input, *out;
+	*argc = 0;
+
+	while (1) {
+		start = end;
+
+		/* Skip whitespace */
+		while (*start && isspace(*start))
+			start++;
+
+		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) > max)
+			return -EINVAL;
+
+		/* we know this is whitespace */
+		if (*end)
+			end++;
+
+		/* terminate the string and put it in the array */
+		*out = '\0';
+		argv[*argc] = start;
+		(*argc)++;
+	}
+
+	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[32];
+	struct dm_target *tgt;
+
+	if ((r = check_space(t)))
+		return r;
+
+	tgt = t->targets + t->num_targets;
+	memset(tgt, 0, sizeof(*tgt));
+
+	tgt->type = dm_get_target_type(type);
+	if (!tgt->type) {
+		tgt->error = "unknown target type";
+		return -EINVAL;
+	}
+
+	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 = split_args(ARRAY_SIZE(argv), &argc, argv, params);
+	if (r) {
+		tgt->error = "couldn't split parameters";
+		goto bad;
+	}
+
+	r = tgt->type->ctr(tgt, argc, argv);
+	if (r)
+		goto bad;
+
+	t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
+	return 0;
+
+      bad:
+	printk(KERN_ERR DM_NAME ": %s\n", tgt->error);
+	dm_put_target_type(tgt->type);
+	return r;
+}
+
+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 *) vcalloc(total, (unsigned long) NODE_SIZE);
+	if (!indexes)
+		return -ENOMEM;
+
+	/* set up internal nodes, bottom-up */
+	for (i = t->depth - 2, total = 0; 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.
+ */
+int dm_table_complete(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;
+}
+
+static spinlock_t _event_lock = SPIN_LOCK_UNLOCKED;
+void dm_table_event_callback(struct dm_table *t,
+			     void (*fn)(void *), void *context)
+{
+	spin_lock_irq(&_event_lock);
+	t->event_fn = fn;
+	t->event_context = context;
+	spin_unlock_irq(&_event_lock);
+}
+
+void dm_table_event(struct dm_table *t)
+{
+	spin_lock(&_event_lock);
+	if (t->event_fn)
+		t->event_fn(t->event_context);
+	spin_unlock(&_event_lock);
+}
+
+sector_t dm_table_get_size(struct dm_table *t)
+{
+	return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
+}
+
+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.
+ */
+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];
+}
+
+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;
+}
+
+int dm_table_get_mode(struct dm_table *t)
+{
+	return t->mode;
+}
+
+void dm_table_suspend_targets(struct dm_table *t)
+{
+	int i;
+
+	for (i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = t->targets + i;
+
+		if (ti->type->suspend)
+			ti->type->suspend(ti);
+	}
+}
+
+void dm_table_resume_targets(struct dm_table *t)
+{
+	int i;
+
+	for (i = 0; i < t->num_targets; i++) {
+		struct dm_target *ti = t->targets + i;
+
+		if (ti->type->resume)
+			ti->type->resume(ti);
+	}
+}
+
+EXPORT_SYMBOL(dm_get_device);
+EXPORT_SYMBOL(dm_put_device);
+EXPORT_SYMBOL(dm_table_event);
+EXPORT_SYMBOL(dm_table_get_mode);