Commit f7671f3d authored by Xie Yongji's avatar Xie Yongji Committed by Michael S. Tsirkin
Browse files

libvhost-user: Introduce vu_queue_map_desc() 



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

Signed-off-by: default avatarXie Yongji <xieyongji@baidu.com>
Signed-off-by: default avatarZhang Yu <zhangyu31@baidu.com>
Reviewed-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20190228085355.9614-4-xieyongji@baidu.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 792468cc

contrib/libvhost-user/libvhost-user.c

+51 −37
Original line number Diff line number Diff line
@@ -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;