virtnet_sq_free_unused_buf
err = virtqueue_resize(sq->vq, ring_num, virtnet_sq_free_unused_buf,
static void virtnet_sq_free_unused_buf(struct virtqueue *vq, void *buf);
err = virtqueue_reset(sq->vq, virtnet_sq_free_unused_buf,
virtnet_sq_free_unused_buf(vq, buf);