nilfs2: remove cruft in nilfs_alloc_seg_bio

bio_alloc never returns NULL when it can sleep.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/nilfs2/segbuf.c

@@ -386,10 +386,6 @@ static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
 	struct bio *bio;
 
 	bio = bio_alloc(GFP_NOIO, nr_vecs);
-	if (bio == NULL) {
-		while (!bio && (nr_vecs >>= 1))
-			bio = bio_alloc(GFP_NOIO, nr_vecs);
-	}
 	if (likely(bio)) {
 		bio_set_dev(bio, nilfs->ns_bdev);
 		bio->bi_iter.bi_sector =