diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index eb9e32995b79..1881d86111fb 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1350,7 +1350,7 @@ void dm_accept_partial_bio(struct bio *bio, unsigned int n_sectors)
 	 * for accounting but it is being reduced so update accordingly.
 	 */
 	dm_io_set_flag(io, DM_IO_WAS_SPLIT);
-	io->sectors = n_sectors;
+	io->sectors = *tio->len_ptr;
 	io->sector_offset = bio_sectors(io->orig_bio);
 }
 EXPORT_SYMBOL_GPL(dm_accept_partial_bio);