On 27.08.2018 03:32, Wei Wang wrote: > static int init_vqs(struct virtio_balloon *vb) > { > - struct virtqueue *vqs[3]; > - vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request }; > - static const char * const names[] = { "inflate", "deflate", "stats" }; > - int err, nvqs; > + struct virtqueue *vqs[VIRTIO_BALLOON_VQ_MAX]; > + vq_callback_t *callbacks[VIRTIO_BALLOON_VQ_MAX]; > + const char *names[VIRTIO_BALLOON_VQ_MAX]; > + int err; > > /* > - * We expect two virtqueues: inflate and deflate, and > - * optionally stat. > + * Inflateq and deflateq are used unconditionally. The names[] > + * will be NULL if the related feature is not enabled, which will > + * cause no allocation for the corresponding virtqueue in find_vqs. > */ This might be true for virtio-pci, but it is not for virtio-ccw. > - nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2; > - err = virtio_find_vqs(vb->vdev, nvqs, vqs, callbacks, names, NULL); > + callbacks[VIRTIO_BALLOON_VQ_INFLATE] = balloon_ack; > + names[VIRTIO_BALLOON_VQ_INFLATE] = "inflate"; > + callbacks[VIRTIO_BALLOON_VQ_DEFLATE] = balloon_ack; > + names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; > + names[VIRTIO_BALLOON_VQ_STATS] = NULL; > + names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; > + > + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { > + names[VIRTIO_BALLOON_VQ_STATS] = "stats"; > + callbacks[VIRTIO_BALLOON_VQ_STATS] = stats_request; > + } > + > + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) { > + names[VIRTIO_BALLOON_VQ_FREE_PAGE] = "free_page_vq"; > + callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; > + } > + > + err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, [...]