block: switch bios to blk_status_t

Replace bi_error with a new bi_status to allow for a clear conversion.
Note that device mapper overloaded bi_error with a private value, which
we'll have to keep arround at least for now and thus propagate to a
proper blk_status_t value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/fs/crypto/bio.c b/fs/crypto/bio.c
index a409a84..6181e95 100644
--- a/fs/crypto/bio.c
+++ b/fs/crypto/bio.c
@@ -129,7 +129,7 @@
 			goto errout;
 		}
 		err = submit_bio_wait(bio);
-		if ((err == 0) && bio->bi_error)
+		if (err == 0 && bio->bi_status)
 			err = -EIO;
 		bio_put(bio);
 		if (err)