X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=drivers%2Fmd%2Fdm-table.c;h=a63161aec48750ef51feb6e6e506c7ff83044dc0;hb=e17be2b2a95b43fe0d5878adf330701bb7a77115;hp=18e9b9953fcd32489a208b273927616da7dd4627;hpb=5e198d94dd0c3ec7f6138229e2e412c2c6268c38;p=safe%2Fjmp%2Flinux-2.6

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 18e9b99..a63161a 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -14,14 +14,18 @@
 #include <linux/ctype.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
+#include <linux/mutex.h>
 #include <asm/atomic.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;
 	atomic_t holders;
 
 	/* btree table */
@@ -39,7 +43,7 @@ struct dm_table {
 	 * device.  This should be a combination of FMODE_READ
 	 * and FMODE_WRITE.
 	 */
-	int mode;
+	fmode_t mode;
 
 	/* a list of devices used by this table */
 	struct list_head devices;
@@ -95,8 +99,15 @@ static void combine_restrictions_low(struct io_restrictions *lhs,
 	lhs->max_segment_size =
 		min_not_zero(lhs->max_segment_size, rhs->max_segment_size);
 
+	lhs->max_hw_sectors =
+		min_not_zero(lhs->max_hw_sectors, rhs->max_hw_sectors);
+
 	lhs->seg_boundary_mask =
 		min_not_zero(lhs->seg_boundary_mask, rhs->seg_boundary_mask);
+
+	lhs->bounce_pfn = min_not_zero(lhs->bounce_pfn, rhs->bounce_pfn);
+
+	lhs->no_cluster |= rhs->no_cluster;
 }
 
 /*
@@ -181,8 +192,10 @@ static int alloc_targets(struct dm_table *t, unsigned int num)
 
 	/*
 	 * 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, sizeof(struct dm_target) +
+	n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
 					  sizeof(sector_t));
 	if (!n_highs)
 		return -ENOMEM;
@@ -204,14 +217,14 @@ static int alloc_targets(struct dm_table *t, unsigned int num)
 	return 0;
 }
 
-int dm_table_create(struct dm_table **result, int mode, unsigned num_targets)
+int dm_table_create(struct dm_table **result, fmode_t mode,
+		    unsigned num_targets, struct mapped_device *md)
 {
-	struct dm_table *t = kmalloc(sizeof(*t), GFP_KERNEL);
+	struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
 
 	if (!t)
 		return -ENOMEM;
 
-	memset(t, 0, sizeof(*t));
 	INIT_LIST_HEAD(&t->devices);
 	atomic_set(&t->holders, 1);
 
@@ -227,6 +240,7 @@ int dm_table_create(struct dm_table **result, int mode, unsigned num_targets)
 	}
 
 	t->mode = mode;
+	t->md = md;
 	*result = t;
 	return 0;
 }
@@ -235,9 +249,9 @@ 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;
+	list_for_each_safe(tmp, next, devices) {
+		struct dm_dev_internal *dd =
+		    list_entry(tmp, struct dm_dev_internal, list);
 		kfree(dd);
 	}
 }
@@ -299,44 +313,14 @@ static inline int check_space(struct dm_table *t)
 }
 
 /*
- * Convert a device path to a dev_t.
- */
-static int lookup_device(const char *path, dev_t *dev)
-{
-	int r;
-	struct nameidata nd;
-	struct inode *inode;
-
-	if ((r = path_lookup(path, LOOKUP_FOLLOW, &nd)))
-		return r;
-
-	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, dev_t dev)
+static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
 {
-	struct dm_dev *dd;
+	struct dm_dev_internal *dd;
 
 	list_for_each_entry (dd, l, list)
-		if (dd->bdev->bd_dev == dev)
+		if (dd->dm_dev.bdev->bd_dev == dev)
 			return dd;
 
 	return NULL;
@@ -345,48 +329,51 @@ static struct dm_dev *find_device(struct list_head *l, dev_t dev)
 /*
  * Open a device so we can use it as a map destination.
  */
-static int open_dev(struct dm_dev *d, dev_t dev)
+static int open_dev(struct dm_dev_internal *d, dev_t dev,
+		    struct mapped_device *md)
 {
 	static char *_claim_ptr = "I belong to device-mapper";
 	struct block_device *bdev;
 
 	int r;
 
-	if (d->bdev)
-		BUG();
+	BUG_ON(d->dm_dev.bdev);
 
-	bdev = open_by_devnum(dev, d->mode);
+	bdev = open_by_devnum(dev, d->dm_dev.mode);
 	if (IS_ERR(bdev))
 		return PTR_ERR(bdev);
-	r = bd_claim(bdev, _claim_ptr);
+	r = bd_claim_by_disk(bdev, _claim_ptr, dm_disk(md));
 	if (r)
-		blkdev_put(bdev);
+		blkdev_put(bdev, d->dm_dev.mode);
 	else
-		d->bdev = bdev;
+		d->dm_dev.bdev = bdev;
 	return r;
 }
 
 /*
  * Close a device that we've been using.
  */
-static void close_dev(struct dm_dev *d)
+static void close_dev(struct dm_dev_internal *d, struct mapped_device *md)
 {
-	if (!d->bdev)
+	if (!d->dm_dev.bdev)
 		return;
 
-	bd_release(d->bdev);
-	blkdev_put(d->bdev);
-	d->bdev = NULL;
+	bd_release_from_disk(d->dm_dev.bdev, dm_disk(md));
+	blkdev_put(d->dm_dev.bdev, d->dm_dev.mode);
+	d->dm_dev.bdev = NULL;
 }
 
 /*
- * If possible (ie. blk_size[major] is set), this checks an area
- * of a destination device is valid.
+ * If possible, this checks an area of a destination device is valid.
  */
-static int check_device_area(struct dm_dev *dd, sector_t start, sector_t len)
+static int check_device_area(struct dm_dev_internal *dd, sector_t start,
+			     sector_t len)
 {
-	sector_t dev_size;
-	dev_size = dd->bdev->bd_inode->i_size >> SECTOR_SHIFT;
+	sector_t dev_size = dd->dm_dev.bdev->bd_inode->i_size >> SECTOR_SHIFT;
+
+	if (!dev_size)
+		return 1;
+
 	return ((start < dev_size) && (len <= (dev_size - start)));
 }
 
@@ -395,19 +382,20 @@ static int check_device_area(struct dm_dev *dd, sector_t start, sector_t len)
  * 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)
+static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
+			struct mapped_device *md)
 {
 	int r;
-	struct dm_dev dd_copy;
-	dev_t dev = dd->bdev->bd_dev;
+	struct dm_dev_internal dd_copy;
+	dev_t dev = dd->dm_dev.bdev->bd_dev;
 
 	dd_copy = *dd;
 
-	dd->mode |= new_mode;
-	dd->bdev = NULL;
-	r = open_dev(dd, dev);
+	dd->dm_dev.mode |= new_mode;
+	dd->dm_dev.bdev = NULL;
+	r = open_dev(dd, dev, md);
 	if (!r)
-		close_dev(&dd_copy);
+		close_dev(&dd_copy, md);
 	else
 		*dd = dd_copy;
 
@@ -420,15 +408,14 @@ static int upgrade_mode(struct dm_dev *dd, int new_mode)
  */
 static int __table_get_device(struct dm_table *t, struct dm_target *ti,
 			      const char *path, sector_t start, sector_t len,
-			      int mode, struct dm_dev **result)
+			      fmode_t mode, struct dm_dev **result)
 {
 	int r;
-	dev_t dev;
-	struct dm_dev *dd;
+	dev_t uninitialized_var(dev);
+	struct dm_dev_internal *dd;
 	unsigned int major, minor;
 
-	if (!t)
-		BUG();
+	BUG_ON(!t);
 
 	if (sscanf(path, "%u:%u", &major, &minor) == 2) {
 		/* Extract the major/minor numbers */
@@ -437,8 +424,12 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
 			return -EOVERFLOW;
 	} else {
 		/* convert the path to a device */
-		if ((r = lookup_device(path, &dev)))
-			return r;
+		struct block_device *bdev = lookup_bdev(path);
+
+		if (IS_ERR(bdev))
+			return PTR_ERR(bdev);
+		dev = bdev->bd_dev;
+		bdput(bdev);
 	}
 
 	dd = find_device(&t->devices, dev);
@@ -447,21 +438,21 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
 		if (!dd)
 			return -ENOMEM;
 
-		dd->mode = mode;
-		dd->bdev = NULL;
+		dd->dm_dev.mode = mode;
+		dd->dm_dev.bdev = NULL;
 
-		if ((r = open_dev(dd, dev))) {
+		if ((r = open_dev(dd, dev, t->md))) {
 			kfree(dd);
 			return r;
 		}
 
-		format_dev_t(dd->name, dev);
+		format_dev_t(dd->dm_dev.name, dev);
 
 		atomic_set(&dd->count, 0);
 		list_add(&dd->list, &t->devices);
 
-	} else if (dd->mode != (mode | dd->mode)) {
-		r = upgrade_mode(dd, mode);
+	} else if (dd->dm_dev.mode != (mode | dd->dm_dev.mode)) {
+		r = upgrade_mode(dd, mode, t->md);
 		if (r)
 			return r;
 	}
@@ -469,63 +460,81 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
 
 	if (!check_device_area(dd, start, len)) {
 		DMWARN("device %s too small for target", path);
-		dm_put_device(ti, dd);
+		dm_put_device(ti, &dd->dm_dev);
 		return -EINVAL;
 	}
 
-	*result = dd;
+	*result = &dd->dm_dev;
 
 	return 0;
 }
 
+void dm_set_device_limits(struct dm_target *ti, struct block_device *bdev)
+{
+	struct request_queue *q = bdev_get_queue(bdev);
+	struct io_restrictions *rs = &ti->limits;
+	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;
+	}
+
+	/*
+	 * Combine the device limits low.
+	 *
+	 * FIXME: if we move an io_restriction struct
+	 *        into q this would just be a call to
+	 *        combine_restrictions_low()
+	 */
+	rs->max_sectors =
+		min_not_zero(rs->max_sectors, q->max_sectors);
+
+	/*
+	 * 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 (q->merge_bvec_fn && !ti->type->merge)
+		rs->max_sectors =
+			min_not_zero(rs->max_sectors,
+				     (unsigned int) (PAGE_SIZE >> 9));
+
+	rs->max_phys_segments =
+		min_not_zero(rs->max_phys_segments,
+			     q->max_phys_segments);
+
+	rs->max_hw_segments =
+		min_not_zero(rs->max_hw_segments, q->max_hw_segments);
+
+	rs->hardsect_size = max(rs->hardsect_size, q->hardsect_size);
+
+	rs->max_segment_size =
+		min_not_zero(rs->max_segment_size, q->max_segment_size);
+
+	rs->max_hw_sectors =
+		min_not_zero(rs->max_hw_sectors, q->max_hw_sectors);
+
+	rs->seg_boundary_mask =
+		min_not_zero(rs->seg_boundary_mask,
+			     q->seg_boundary_mask);
+
+	rs->bounce_pfn = min_not_zero(rs->bounce_pfn, q->bounce_pfn);
+
+	rs->no_cluster |= !test_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
+}
+EXPORT_SYMBOL_GPL(dm_set_device_limits);
 
 int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
-		  sector_t len, int mode, struct dm_dev **result)
+		  sector_t len, fmode_t mode, struct dm_dev **result)
 {
 	int r = __table_get_device(ti->table, ti, path,
 				   start, len, mode, result);
-	if (!r) {
-		request_queue_t *q = bdev_get_queue((*result)->bdev);
-		struct io_restrictions *rs = &ti->limits;
-
-		/*
-		 * Combine the device limits low.
-		 *
-		 * FIXME: if we move an io_restriction struct
-		 *        into q this would just be a call to
-		 *        combine_restrictions_low()
-		 */
-		rs->max_sectors =
-			min_not_zero(rs->max_sectors, q->max_sectors);
-
-		/* FIXME: Device-Mapper on top of RAID-0 breaks because DM
-		 *        currently doesn't honor MD's merge_bvec_fn routine.
-		 *        In this case, we'll force DM to use PAGE_SIZE or
-		 *        smaller I/O, just to be safe. A better fix is in the
-		 *        works, but add this for the time being so it will at
-		 *        least operate correctly.
-		 */
-		if (q->merge_bvec_fn)
-			rs->max_sectors =
-				min_not_zero(rs->max_sectors,
-					     (unsigned short)(PAGE_SIZE >> 9));
-
-		rs->max_phys_segments =
-			min_not_zero(rs->max_phys_segments,
-				     q->max_phys_segments);
-
-		rs->max_hw_segments =
-			min_not_zero(rs->max_hw_segments, q->max_hw_segments);
-
-		rs->hardsect_size = max(rs->hardsect_size, q->hardsect_size);
-
-		rs->max_segment_size =
-			min_not_zero(rs->max_segment_size, q->max_segment_size);
-
-		rs->seg_boundary_mask =
-			min_not_zero(rs->seg_boundary_mask,
-				     q->seg_boundary_mask);
-	}
+
+	if (!r)
+		dm_set_device_limits(ti, (*result)->bdev);
 
 	return r;
 }
@@ -533,10 +542,13 @@ int dm_get_device(struct dm_target *ti, const char *path, sector_t start,
 /*
  * Decrement a devices use count and remove it if necessary.
  */
-void dm_put_device(struct dm_target *ti, struct dm_dev *dd)
+void dm_put_device(struct dm_target *ti, struct dm_dev *d)
 {
+	struct dm_dev_internal *dd = container_of(d, struct dm_dev_internal,
+						  dm_dev);
+
 	if (atomic_dec_and_test(&dd->count)) {
-		close_dev(dd);
+		close_dev(dd, ti->table->md);
 		list_del(&dd->list);
 		kfree(dd);
 	}
@@ -584,6 +596,12 @@ int dm_split_args(int *argc, char ***argvp, char *input)
 	unsigned array_size = 0;
 
 	*argc = 0;
+
+	if (!input) {
+		*argvp = NULL;
+		return 0;
+	}
+
 	argv = realloc_argv(&array_size, argv);
 	if (!argv)
 		return -ENOMEM;
@@ -638,7 +656,9 @@ int dm_split_args(int *argc, char ***argvp, char *input)
 static void check_for_valid_limits(struct io_restrictions *rs)
 {
 	if (!rs->max_sectors)
-		rs->max_sectors = MAX_SECTORS;
+		rs->max_sectors = SAFE_MAX_SECTORS;
+	if (!rs->max_hw_sectors)
+		rs->max_hw_sectors = SAFE_MAX_SECTORS;
 	if (!rs->max_phys_segments)
 		rs->max_phys_segments = MAX_PHYS_SEGMENTS;
 	if (!rs->max_hw_segments)
@@ -649,6 +669,8 @@ static void check_for_valid_limits(struct io_restrictions *rs)
 		rs->max_segment_size = MAX_SEGMENT_SIZE;
 	if (!rs->seg_boundary_mask)
 		rs->seg_boundary_mask = -1;
+	if (!rs->bounce_pfn)
+		rs->bounce_pfn = -1;
 }
 
 int dm_table_add_target(struct dm_table *t, const char *type,
@@ -665,15 +687,14 @@ int dm_table_add_target(struct dm_table *t, const char *type,
 	memset(tgt, 0, sizeof(*tgt));
 
 	if (!len) {
-		tgt->error = "zero-length target";
-		DMERR("%s", tgt->error);
+		DMERR("%s: zero-length target", dm_device_name(t->md));
 		return -EINVAL;
 	}
 
 	tgt->type = dm_get_target_type(type);
 	if (!tgt->type) {
-		tgt->error = "unknown target type";
-		DMERR("%s", tgt->error);
+		DMERR("%s: %s: unknown target type", dm_device_name(t->md),
+		      type);
 		return -EINVAL;
 	}
 
@@ -710,7 +731,7 @@ int dm_table_add_target(struct dm_table *t, const char *type,
 	return 0;
 
  bad:
-	DMERR("%s", tgt->error);
+	DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
 	dm_put_target_type(tgt->type);
 	return r;
 }
@@ -732,7 +753,7 @@ static int setup_indexes(struct dm_table *t)
 		return -ENOMEM;
 
 	/* set up internal nodes, bottom-up */
-	for (i = t->depth - 2, total = 0; i >= 0; i--) {
+	for (i = t->depth - 2; i >= 0; i--) {
 		t->index[i] = indexes;
 		indexes += (KEYS_PER_NODE * t->counts[i]);
 		setup_btree_index(i, t);
@@ -765,14 +786,14 @@ int dm_table_complete(struct dm_table *t)
 	return r;
 }
 
-static DECLARE_MUTEX(_event_lock);
+static DEFINE_MUTEX(_event_lock);
 void dm_table_event_callback(struct dm_table *t,
 			     void (*fn)(void *), void *context)
 {
-	down(&_event_lock);
+	mutex_lock(&_event_lock);
 	t->event_fn = fn;
 	t->event_context = context;
-	up(&_event_lock);
+	mutex_unlock(&_event_lock);
 }
 
 void dm_table_event(struct dm_table *t)
@@ -783,10 +804,10 @@ void dm_table_event(struct dm_table *t)
 	 */
 	BUG_ON(in_interrupt());
 
-	down(&_event_lock);
+	mutex_lock(&_event_lock);
 	if (t->event_fn)
 		t->event_fn(t->event_context);
-	up(&_event_lock);
+	mutex_unlock(&_event_lock);
 }
 
 sector_t dm_table_get_size(struct dm_table *t)
@@ -796,7 +817,7 @@ sector_t dm_table_get_size(struct dm_table *t)
 
 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
 {
-	if (index > t->num_targets)
+	if (index >= t->num_targets)
 		return NULL;
 
 	return t->targets + index;
@@ -804,6 +825,9 @@ struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int 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)
 {
@@ -833,7 +857,15 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q)
 	q->max_hw_segments = t->limits.max_hw_segments;
 	q->hardsect_size = t->limits.hardsect_size;
 	q->max_segment_size = t->limits.max_segment_size;
+	q->max_hw_sectors = t->limits.max_hw_sectors;
 	q->seg_boundary_mask = t->limits.seg_boundary_mask;
+	q->bounce_pfn = t->limits.bounce_pfn;
+
+	if (t->limits.no_cluster)
+		queue_flag_clear_unlocked(QUEUE_FLAG_CLUSTER, q);
+	else
+		queue_flag_set_unlocked(QUEUE_FLAG_CLUSTER, q);
+
 }
 
 unsigned int dm_table_get_num_targets(struct dm_table *t)
@@ -846,7 +878,7 @@ struct list_head *dm_table_get_devices(struct dm_table *t)
 	return &t->devices;
 }
 
-int dm_table_get_mode(struct dm_table *t)
+fmode_t dm_table_get_mode(struct dm_table *t)
 {
 	return t->mode;
 }
@@ -869,17 +901,34 @@ static void suspend_targets(struct dm_table *t, unsigned postsuspend)
 
 void dm_table_presuspend_targets(struct dm_table *t)
 {
-	return suspend_targets(t, 0);
+	if (!t)
+		return;
+
+	suspend_targets(t, 0);
 }
 
 void dm_table_postsuspend_targets(struct dm_table *t)
 {
-	return suspend_targets(t, 1);
+	if (!t)
+		return;
+
+	suspend_targets(t, 1);
 }
 
-void dm_table_resume_targets(struct dm_table *t)
+int dm_table_resume_targets(struct dm_table *t)
 {
-	int i;
+	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)
+			return r;
+	}
 
 	for (i = 0; i < t->num_targets; i++) {
 		struct dm_target *ti = t->targets + i;
@@ -887,18 +936,26 @@ void dm_table_resume_targets(struct dm_table *t)
 		if (ti->type->resume)
 			ti->type->resume(ti);
 	}
+
+	return 0;
 }
 
 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
 {
-	struct list_head *d, *devices;
+	struct dm_dev_internal *dd;
+	struct list_head *devices = dm_table_get_devices(t);
 	int r = 0;
 
-	devices = dm_table_get_devices(t);
-	for (d = devices->next; d != devices; d = d->next) {
-		struct dm_dev *dd = list_entry(d, struct dm_dev, list);
-		request_queue_t *q = bdev_get_queue(dd->bdev);
-		r |= bdi_congested(&q->backing_dev_info, bdi_bits);
+	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));
 	}
 
 	return r;
@@ -906,45 +963,36 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits)
 
 void dm_table_unplug_all(struct dm_table *t)
 {
-	struct list_head *d, *devices = dm_table_get_devices(t);
+	struct dm_dev_internal *dd;
+	struct list_head *devices = dm_table_get_devices(t);
 
-	for (d = devices->next; d != devices; d = d->next) {
-		struct dm_dev *dd = list_entry(d, struct dm_dev, list);
-		request_queue_t *q = bdev_get_queue(dd->bdev);
+	list_for_each_entry(dd, devices, list) {
+		struct request_queue *q = bdev_get_queue(dd->dm_dev.bdev);
+		char b[BDEVNAME_SIZE];
 
-		if (q->unplug_fn)
-			q->unplug_fn(q);
+		if (likely(q))
+			blk_unplug(q);
+		else
+			DMWARN_LIMIT("%s: Cannot unplug nonexistent device %s",
+				     dm_device_name(t->md),
+				     bdevname(dd->dm_dev.bdev, b));
 	}
 }
 
-int dm_table_flush_all(struct dm_table *t)
+struct mapped_device *dm_table_get_md(struct dm_table *t)
 {
-	struct list_head *d, *devices = dm_table_get_devices(t);
-	int ret = 0;
-
-	for (d = devices->next; d != devices; d = d->next) {
-		struct dm_dev *dd = list_entry(d, struct dm_dev, list);
-		request_queue_t *q = bdev_get_queue(dd->bdev);
-		int err;
-
-		if (!q->issue_flush_fn)
-			err = -EOPNOTSUPP;
-		else
-			err = q->issue_flush_fn(q, dd->bdev->bd_disk, NULL);
-
-		if (!ret)
-			ret = err;
-	}
+	dm_get(t->md);
 
-	return ret;
+	return t->md;
 }
 
 EXPORT_SYMBOL(dm_vcalloc);
 EXPORT_SYMBOL(dm_get_device);
 EXPORT_SYMBOL(dm_put_device);
 EXPORT_SYMBOL(dm_table_event);
+EXPORT_SYMBOL(dm_table_get_size);
 EXPORT_SYMBOL(dm_table_get_mode);
+EXPORT_SYMBOL(dm_table_get_md);
 EXPORT_SYMBOL(dm_table_put);
 EXPORT_SYMBOL(dm_table_get);
 EXPORT_SYMBOL(dm_table_unplug_all);
-EXPORT_SYMBOL(dm_table_flush_all);