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-exception-store.c b/drivers/md/dm-exception-store.c
index c7d305b..6933301 100644
--- a/drivers/md/dm-exception-store.c
+++ b/drivers/md/dm-exception-store.c
@@ -159,7 +159,7 @@
 }
 
 struct mdata_req {
-	struct io_region *where;
+	struct dm_io_region *where;
 	struct dm_io_request *io_req;
 	struct work_struct work;
 	int result;
@@ -177,7 +177,7 @@
  */
 static int chunk_io(struct pstore *ps, uint32_t chunk, int rw, int metadata)
 {
-	struct io_region where = {
+	struct dm_io_region where = {
 		.bdev = ps->snap->cow->bdev,
 		.sector = ps->snap->chunk_size * chunk,
 		.count = ps->snap->chunk_size,