Drop 'size' argument from bio_endio and bi_end_io

As bi_end_io is only called once when the reqeust is complete,
the 'size' argument is now redundant.  Remove it.

Now there is no need for bio_endio to subtract the size completed
from bi_size.  So don't do that either.

While we are at it, change bi_end_io to return void.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index f3a7724..b8e342f 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -124,15 +124,11 @@
 	}
 }
 
-static int endio(struct bio *bio, unsigned int done, int error)
+static void endio(struct bio *bio, int error)
 {
 	struct io *io;
 	unsigned region;
 
-	/* keep going until we've finished */
-	if (bio->bi_size)
-		return 1;
-
 	if (error && bio_data_dir(bio) == READ)
 		zero_fill_bio(bio);
 
@@ -146,8 +142,6 @@
 	bio_put(bio);
 
 	dec_count(io, region, error);
-
-	return 0;
 }
 
 /*-----------------------------------------------------------------