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libvhost-user: Introduce vu_queue_map_desc()

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Introduce vu_queue_map_desc() which should be
independent with vu_queue_pop();

Signed-off-by: Xie Yongji <xieyongji@baidu.com>
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190228085355.9614-4-xieyongji@baidu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Xie Yongji 2019-02-28 16:53:51 +08:00 committed by Michael S. Tsirkin
parent 792468cc6f
commit f7671f3d49
1 changed files with 51 additions and 37 deletions
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88
contrib/libvhost-user/libvhost-user.c
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@ -1848,49 +1848,20 @@ virtqueue_alloc_element(size_t sz,
return elem;
}
void *
vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
static void *
vu_queue_map_desc(VuDev *dev, VuVirtq *vq, unsigned int idx, size_t sz)
{
unsigned int i, head, max, desc_len;
struct vring_desc *desc = vq->vring.desc;
uint64_t desc_addr, read_len;
unsigned int desc_len;
unsigned int max = vq->vring.num;
unsigned int i = idx;
VuVirtqElement *elem;
unsigned out_num, in_num;
unsigned int out_num = 0, in_num = 0;
struct iovec iov[VIRTQUEUE_MAX_SIZE];
struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
struct vring_desc *desc;
int rc;
if (unlikely(dev->broken) ||
unlikely(!vq->vring.avail)) {
return NULL;
}
if (vu_queue_empty(dev, vq)) {
return NULL;
}
/* Needed after virtio_queue_empty(), see comment in
* virtqueue_num_heads(). */
smp_rmb();
/* When we start there are none of either input nor output. */
out_num = in_num = 0;
max = vq->vring.num;
if (vq->inuse >= vq->vring.num) {
vu_panic(dev, "Virtqueue size exceeded");
return NULL;
}
if (!virtqueue_get_head(dev, vq, vq->last_avail_idx++, &head)) {
return NULL;
}
if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
vring_set_avail_event(vq, vq->last_avail_idx);
}
i = head;
desc = vq->vring.desc;
if (desc[i].flags & VRING_DESC_F_INDIRECT) {
if (desc[i].len % sizeof(struct vring_desc)) {
vu_panic(dev, "Invalid size for indirect buffer table");
@ -1942,12 +1913,13 @@ vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
} while (rc == VIRTQUEUE_READ_DESC_MORE);
if (rc == VIRTQUEUE_READ_DESC_ERROR) {
vu_panic(dev, "read descriptor error");
return NULL;
}
/* Now copy what we have collected and mapped */
elem = virtqueue_alloc_element(sz, out_num, in_num);
elem->index = head;
elem->index = idx;
for (i = 0; i < out_num; i++) {
elem->out_sg[i] = iov[i];
}
@ -1955,6 +1927,48 @@ vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
elem->in_sg[i] = iov[out_num + i];
}
return elem;
}
void *
vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
{
unsigned int head;
VuVirtqElement *elem;
if (unlikely(dev->broken) ||
unlikely(!vq->vring.avail)) {
return NULL;
}
if (vu_queue_empty(dev, vq)) {
return NULL;
}
/*
* Needed after virtio_queue_empty(), see comment in
* virtqueue_num_heads().
*/
smp_rmb();
if (vq->inuse >= vq->vring.num) {
vu_panic(dev, "Virtqueue size exceeded");
return NULL;
}
if (!virtqueue_get_head(dev, vq, vq->last_avail_idx++, &head)) {
return NULL;
}
if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
vring_set_avail_event(vq, vq->last_avail_idx);
}
elem = vu_queue_map_desc(dev, vq, head, sz);
if (!elem) {
return NULL;
}
vq->inuse++;
return elem;