block: reset bi_iter.bi_done after splitting bio

After the bio has been updated to represent the remaining sectors, reset
bi_done so bio_rewind_iter() does not rewind further than it should.

This resolves a bio_integrity_process() failure on reads where the
original request was split.

Fixes: 63573e35 ("bio-integrity: Restore original iterator on verify stage")
Signed-off-by: Greg Edwards <gedwards@ddn.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bio.c

@@ -1893,6 +1893,7 @@ struct bio *bio_split(struct bio *bio, int sectors,
 		bio_integrity_trim(split);
 
 	bio_advance(bio, split->bi_iter.bi_size);
+	bio->bi_iter.bi_done = 0;
 
 	if (bio_flagged(bio, BIO_TRACE_COMPLETION))
 		bio_set_flag(split, BIO_TRACE_COMPLETION);