vsock/virtio: remove loopback handling

We can remove the loopback handling from virtio_transport,
because now the vsock core is able to handle local communication
using the new vsock_loopback device.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/vmw_vsock/virtio_transport.c

@@ -44,10 +44,6 @@ struct virtio_vsock {
 	spinlock_t send_pkt_list_lock;
 	struct list_head send_pkt_list;
 
-	struct work_struct loopback_work;
-	spinlock_t loopback_list_lock; /* protects loopback_list */
-	struct list_head loopback_list;
-
 	atomic_t queued_replies;
 
 	/* The following fields are protected by rx_lock.  vqs[VSOCK_VQ_RX]
@@ -86,20 +82,6 @@ static u32 virtio_transport_get_local_cid(void)
 	return ret;
 }
 
-static int virtio_transport_send_pkt_loopback(struct virtio_vsock *vsock,
-					      struct virtio_vsock_pkt *pkt)
-{
-	int len = pkt->len;
-
-	spin_lock_bh(&vsock->loopback_list_lock);
-	list_add_tail(&pkt->list, &vsock->loopback_list);
-	spin_unlock_bh(&vsock->loopback_list_lock);
-
-	queue_work(virtio_vsock_workqueue, &vsock->loopback_work);
-
-	return len;
-}
-
 static void
 virtio_transport_send_pkt_work(struct work_struct *work)
 {
@@ -194,7 +176,8 @@ virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt)
 	}
 
 	if (le64_to_cpu(pkt->hdr.dst_cid) == vsock->guest_cid) {
-		len = virtio_transport_send_pkt_loopback(vsock, pkt);
+		virtio_transport_free_pkt(pkt);
+		len = -ENODEV;
 		goto out_rcu;
 	}
 
@@ -502,33 +485,6 @@ static struct virtio_transport virtio_transport = {
 	.send_pkt = virtio_transport_send_pkt,
 };
 
-static void virtio_transport_loopback_work(struct work_struct *work)
-{
-	struct virtio_vsock *vsock =
-		container_of(work, struct virtio_vsock, loopback_work);
-	LIST_HEAD(pkts);
-
-	spin_lock_bh(&vsock->loopback_list_lock);
-	list_splice_init(&vsock->loopback_list, &pkts);
-	spin_unlock_bh(&vsock->loopback_list_lock);
-
-	mutex_lock(&vsock->rx_lock);
-
-	if (!vsock->rx_run)
-		goto out;
-
-	while (!list_empty(&pkts)) {
-		struct virtio_vsock_pkt *pkt;
-
-		pkt = list_first_entry(&pkts, struct virtio_vsock_pkt, list);
-		list_del_init(&pkt->list);
-
-		virtio_transport_recv_pkt(&virtio_transport, pkt);
-	}
-out:
-	mutex_unlock(&vsock->rx_lock);
-}
-
 static void virtio_transport_rx_work(struct work_struct *work)
 {
 	struct virtio_vsock *vsock =
@@ -633,13 +589,10 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
 	mutex_init(&vsock->event_lock);
 	spin_lock_init(&vsock->send_pkt_list_lock);
 	INIT_LIST_HEAD(&vsock->send_pkt_list);
-	spin_lock_init(&vsock->loopback_list_lock);
-	INIT_LIST_HEAD(&vsock->loopback_list);
 	INIT_WORK(&vsock->rx_work, virtio_transport_rx_work);
 	INIT_WORK(&vsock->tx_work, virtio_transport_tx_work);
 	INIT_WORK(&vsock->event_work, virtio_transport_event_work);
 	INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work);
-	INIT_WORK(&vsock->loopback_work, virtio_transport_loopback_work);
 
 	mutex_lock(&vsock->tx_lock);
 	vsock->tx_run = true;
@@ -720,22 +673,12 @@ static void virtio_vsock_remove(struct virtio_device *vdev)
 	}
 	spin_unlock_bh(&vsock->send_pkt_list_lock);
 
-	spin_lock_bh(&vsock->loopback_list_lock);
-	while (!list_empty(&vsock->loopback_list)) {
-		pkt = list_first_entry(&vsock->loopback_list,
-				       struct virtio_vsock_pkt, list);
-		list_del(&pkt->list);
-		virtio_transport_free_pkt(pkt);
-	}
-	spin_unlock_bh(&vsock->loopback_list_lock);
-
 	/* Delete virtqueues and flush outstanding callbacks if any */
 	vdev->config->del_vqs(vdev);
 
 	/* Other works can be queued before 'config->del_vqs()', so we flush
 	 * all works before to free the vsock object to avoid use after free.
 	 */
-	flush_work(&vsock->loopback_work);
 	flush_work(&vsock->rx_work);
 	flush_work(&vsock->tx_work);
 	flush_work(&vsock->event_work);