squashfs: always use bio_kmalloc in squashfs_bio_read

If a plain kmalloc that is not backed by a mempool is safe here for a
large read (and the actual page allocations), it must also be for a
small one, so simplify the code a bit.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Phillip Lougher <phillip@squashfs.org.uk>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20220406061228.410163-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/squashfs/block.c

@@ -86,16 +86,11 @@ static int squashfs_bio_read(struct super_block *sb, u64 index, int length,
 	int error, i;
 	struct bio *bio;
 
-	if (page_count <= BIO_MAX_VECS) {
-		bio = bio_alloc(sb->s_bdev, page_count, REQ_OP_READ, GFP_NOIO);
-	} else {
-		bio = bio_kmalloc(GFP_NOIO, page_count);
-		bio_set_dev(bio, sb->s_bdev);
-		bio->bi_opf = REQ_OP_READ;
-	}
-
+	bio = bio_kmalloc(GFP_NOIO, page_count);
 	if (!bio)
 		return -ENOMEM;
+	bio_set_dev(bio, sb->s_bdev);
+	bio->bi_opf = REQ_OP_READ;
 
 	bio->bi_iter.bi_sector = block * (msblk->devblksize >> SECTOR_SHIFT);