dm io: clean interface

Clean up the dm-io interface to prepare for publishing it in include/linux.

Signed-off-by: Heinz Mauelshagen <hjm@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c
index 08a8cbd..bab159b 100644
--- a/drivers/md/dm-snap.c
+++ b/drivers/md/dm-snap.c
@@ -824,7 +824,7 @@
 static void start_copy(struct dm_snap_pending_exception *pe)
 {
 	struct dm_snapshot *s = pe->snap;
-	struct io_region src, dest;
+	struct dm_io_region src, dest;
 	struct block_device *bdev = s->origin->bdev;
 	sector_t dev_size;