Function rte_vhost_dequeue_burst

dpdk/lib/vhost/virtio_net.c:3560–3670

}

uint16_t
rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
	struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count)
{
	struct virtio_net *dev;
	struct rte_mbuf *rarp_mbuf = NULL;
	struct vhost_virtqueue *vq;
	int16_t success = 1;

	dev = get_device(vid);
	if (!dev)
		return 0;

	if (unlikely(!(dev->flags & VIRTIO_DEV_BUILTIN_VIRTIO_NET))) {
		VHOST_LOG_DATA(dev->ifname, ERR,
			"%s: built-in vhost net backend is disabled.\n",
			__func__);
		return 0;
	}

	if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->nr_vring))) {
		VHOST_LOG_DATA(dev->ifname, ERR,
			"%s: invalid virtqueue idx %d.\n",
			__func__, queue_id);
		return 0;
	}

	vq = dev->virtqueue[queue_id];

	if (unlikely(rte_rwlock_read_trylock(&vq->access_lock) != 0))
		return 0;

	if (unlikely(!vq->enabled)) {
		count = 0;
		goto out_access_unlock;
	}

	vhost_user_iotlb_rd_lock(vq);

	if (unlikely(!vq->access_ok)) {
		vhost_user_iotlb_rd_unlock(vq);
		rte_rwlock_read_unlock(&vq->access_lock);

		virtio_dev_vring_translate(dev, vq);

		count = 0;
		goto out_no_unlock;
	}

	/*
	 * Construct a RARP broadcast packet, and inject it to the "pkts"
	 * array, to looks like that guest actually send such packet.
	 *
	 * Check user_send_rarp() for more information.
	 *
	 * broadcast_rarp shares a cacheline in the virtio_net structure
	 * with some fields that are accessed during enqueue and
	 * rte_atomic_compare_exchange_strong_explicit causes a write if performed compare