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/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
index aef6fd7..79b90d8 100644
--- a/drivers/lightnvm/pblk-write.c
+++ b/drivers/lightnvm/pblk-write.c
@@ -186,7 +186,7 @@
 	}
 #ifdef CONFIG_NVM_DEBUG
 	else
-		WARN_ONCE(rqd->bio->bi_error, "pblk: corrupted write error\n");
+		WARN_ONCE(rqd->bio->bi_status, "pblk: corrupted write error\n");
 #endif
 
 	pblk_complete_write(pblk, rqd, c_ctx);