static void stats_handle_request(struct virtio_balloon *vb)
{
struct virtqueue *vq;
struct scatterlist sg;
unsigned int len, num_stats;
num_stats = update_balloon_stats(vb);
vq = vb->stats_vq;
if (!virtqueue_get_buf(vq, &len))
return;
sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats);
virtqueue_add_outbuf(vq, &sg, 1, vb, GFP_KERNEL);
virtqueue_kick(vq);
}
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;
/*
* We expect two virtqueues: inflate and deflate, and
* optionally stat.
*/
nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2;
err = virtio_find_vqs(vb->vdev, nvqs, vqs, callbacks, names, NULL);
if (err)
return err;
vb->inflate_vq = vqs[0];
vb->deflate_vq = vqs[1];
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
struct scatterlist sg;
unsigned int num_stats;
vb->stats_vq = vqs[2];
/*
* Prime this virtqueue with one buffer so the hypervisor can
* use it to signal us later (it can't be broken yet!).
*/
num_stats = update_balloon_stats(vb);
sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats);
if (virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb, GFP_KERNEL)
< 0)
BUG();
virtqueue_kick(vb->stats_vq);
}
return 0;
}
static int init_vqs(struct virtio_balloon *vb)
{
struct virtqueue *vqs[VIRTIO_BALLOON_VQ_MAX];
vq_callback_t *callbacks[VIRTIO_BALLOON_VQ_MAX];
const char *names[VIRTIO_BALLOON_VQ_MAX];
int err;
/*
* 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.
*/
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,
vqs, callbacks, names, NULL, NULL);
if (err)
return err;
vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE];
vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE];
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) {
struct scatterlist sg;
unsigned int num_stats;
vb->stats_vq = vqs[VIRTIO_BALLOON_VQ_STATS];
/*
* Prime this virtqueue with one buffer so the hypervisor can
* use it to signal us later (it can't be broken yet!).
*/
num_stats = update_balloon_stats(vb);
sg_init_one(&sg, vb->stats, sizeof(vb->stats[0]) * num_stats);
err = virtqueue_add_outbuf(vb->stats_vq, &sg, 1, vb,
GFP_KERNEL);
if (err) {
dev_warn(&vb->vdev->dev, "%s: add stat_vq failed\n",
__func__);
return err;
}
virtqueue_kick(vb->stats_vq);
}
if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT))
vb->free_page_vq = vqs[VIRTIO_BALLOON_VQ_FREE_PAGE];
return 0;
}