nilfs2: remove nilfs_alloc_seg_bio

bio_alloc will never fail when it can sleep.  Remove the now simple
nilfs_alloc_seg_bio helper and open code it in the only caller.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220124091107.642561-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/nilfs2/segbuf.c

@@ -371,29 +371,6 @@ static int nilfs_segbuf_submit_bio(struct nilfs_segment_buffer *segbuf,
 	return err;
 }
 
-/**
- * nilfs_alloc_seg_bio - allocate a new bio for writing log
- * @nilfs: nilfs object
- * @start: start block number of the bio
- * @nr_vecs: request size of page vector.
- *
- * Return Value: On success, pointer to the struct bio is returned.
- * On error, NULL is returned.
- */
-static struct bio *nilfs_alloc_seg_bio(struct the_nilfs *nilfs, sector_t start,
-				       int nr_vecs)
-{
-	struct bio *bio;
-
-	bio = bio_alloc(GFP_NOIO, nr_vecs);
-	if (likely(bio)) {
-		bio_set_dev(bio, nilfs->ns_bdev);
-		bio->bi_iter.bi_sector =
-			start << (nilfs->ns_blocksize_bits - 9);
-	}
-	return bio;
-}
-
 static void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *segbuf,
 				       struct nilfs_write_info *wi)
 {
@@ -414,10 +391,10 @@ static int nilfs_segbuf_submit_bh(struct nilfs_segment_buffer *segbuf,
 	BUG_ON(wi->nr_vecs <= 0);
  repeat:
 	if (!wi->bio) {
-		wi->bio = nilfs_alloc_seg_bio(wi->nilfs, wi->blocknr + wi->end,
-					      wi->nr_vecs);
-		if (unlikely(!wi->bio))
-			return -ENOMEM;
+		wi->bio = bio_alloc(GFP_NOIO, wi->nr_vecs);
+		bio_set_dev(wi->bio, wi->nilfs->ns_bdev);
+		wi->bio->bi_iter.bi_sector = (wi->blocknr + wi->end) <<
+			(wi->nilfs->ns_blocksize_bits - 9);
 	}
 
 	len = bio_add_page(wi->bio, bh->b_page, bh->b_size, bh_offset(bh));