static void vhost_vsock_handle_tx_kick()

in vsock.c [493:564]

• 53 lines of code
• 12 McCabe index (conditional complexity)

static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
{
	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
						  poll.work);
	struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock,
						 dev);
	struct virtio_vsock_pkt *pkt;
	int head, pkts = 0, total_len = 0;
	unsigned int out, in;
	bool added = false;

	mutex_lock(&vq->mutex);

	if (!vhost_vq_get_backend(vq))
		goto out;

	if (!vq_meta_prefetch(vq))
		goto out;

	vhost_disable_notify(&vsock->dev, vq);
	do {
		if (!vhost_vsock_more_replies(vsock)) {
			/* Stop tx until the device processes already
			 * pending replies.  Leave tx virtqueue
			 * callbacks disabled.
			 */
			goto no_more_replies;
		}

		head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
					 &out, &in, NULL, NULL);
		if (head < 0)
			break;

		if (head == vq->num) {
			if (unlikely(vhost_enable_notify(&vsock->dev, vq))) {
				vhost_disable_notify(&vsock->dev, vq);
				continue;
			}
			break;
		}

		pkt = vhost_vsock_alloc_pkt(vq, out, in);
		if (!pkt) {
			vq_err(vq, "Faulted on pkt\n");
			continue;
		}

		total_len += sizeof(pkt->hdr) + pkt->len;

		/* Deliver to monitoring devices all received packets */
		virtio_transport_deliver_tap_pkt(pkt);

		/* Only accept correctly addressed packets */
		if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid &&
		    le64_to_cpu(pkt->hdr.dst_cid) ==
		    vhost_transport_get_local_cid())
			virtio_transport_recv_pkt(&vhost_transport, pkt);
		else
			virtio_transport_free_pkt(pkt);

		vhost_add_used(vq, head, 0);
		added = true;
	} while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));

no_more_replies:
	if (added)
		vhost_signal(&vsock->dev, vq);

out:
	mutex_unlock(&vq->mutex);
}