dm table: pass correct dev area size to device_area_is_valid

Incorrect device area lengths are being passed to device_area_is_valid().

The regression appeared in 2.6.31-rc1 through commit
754c5fc7eb.

With the dm-stripe target, the size of the target (ti->len) was used
instead of the stripe_width (ti->len/#stripes).  An example of a
consequent incorrect error message is:

  device-mapper: table: 254:0: sdb too small for target

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

drivers/md/dm-table.c

@@ -346,7 +346,7 @@ static void close_dev(struct dm_dev_internal *d, struct mapped_device *md)
  * If possible, this checks an area of a destination device is valid.
  */
 static int device_area_is_valid(struct dm_target *ti, struct dm_dev *dev,
-				sector_t start, void *data)
+				sector_t start, sector_t len, void *data)
 {
 	struct queue_limits *limits = data;
 	struct block_device *bdev = dev->bdev;
@@ -359,7 +359,7 @@ static int device_area_is_valid(struct dm_target *ti, struct dm_dev *dev,
 	if (!dev_size)
 		return 1;
 
-	if ((start >= dev_size) || (start + ti->len > dev_size)) {
+	if ((start >= dev_size) || (start + len > dev_size)) {
 		DMWARN("%s: %s too small for target",
 		       dm_device_name(ti->table->md), bdevname(bdev, b));
 		return 0;
@@ -377,11 +377,11 @@ static int device_area_is_valid(struct dm_target *ti, struct dm_dev *dev,
 		return 0;
 	}
 
-	if (ti->len & (logical_block_size_sectors - 1)) {
+	if (len & (logical_block_size_sectors - 1)) {
 		DMWARN("%s: len=%llu not aligned to h/w "
 		       "logical block size %hu of %s",
 		       dm_device_name(ti->table->md),
-		       (unsigned long long)ti->len,
+		       (unsigned long long)len,
 		       limits->logical_block_size, bdevname(bdev, b));
 		return 0;
 	}
@@ -482,7 +482,7 @@ static int __table_get_device(struct dm_table *t, struct dm_target *ti,
 #define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
 
 int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
-			 sector_t start, void *data)
+			 sector_t start, sector_t len, void *data)
 {
 	struct queue_limits *limits = data;
 	struct block_device *bdev = dev->bdev;