Merge branch 'vsock-virtio-fixes-about-packet-delivery-to-monitoring-…

…devices'

Stefano Garzarella says:

====================
vsock/virtio: fixes about packet delivery to monitoring devices

During the review of v1, Stefan pointed out an issue introduced by
that patch, where replies can appear in the packet capture before
the transmitted packet.

While fixing my patch, reverting it and adding a new flag in
'struct virtio_vsock_pkt' (patch 2/2), I found that we already had
that issue in vhost-vsock, so I fixed it (patch 1/2).

v1 -> v2:
- reverted the v1 patch, to avoid that replies can appear in the
  packet capture before the transmitted packet [Stefan]
- added patch to fix packet delivering to monitoring devices in
  vhost-vsock
- added patch to check if the packet is already delivered to
  monitoring devices

v1: https://patchwork.ozlabs.org/project/netdev/patch/20200421092527.41651-1-sgarzare@redhat.com/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/vhost/vsock.c

@@ -181,21 +181,27 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
 			break;
 		}
 
-		vhost_add_used(vq, head, sizeof(pkt->hdr) + payload_len);
-		added = true;
-
-		/* Deliver to monitoring devices all correctly transmitted
-		 * packets.
+		/* Deliver to monitoring devices all packets that we
+		 * will transmit.
 		 */
 		virtio_transport_deliver_tap_pkt(pkt);
 
+		vhost_add_used(vq, head, sizeof(pkt->hdr) + payload_len);
+		added = true;
+
 		pkt->off += payload_len;
 		total_len += payload_len;
 
 		/* If we didn't send all the payload we can requeue the packet
 		 * to send it with the next available buffer.
 		 */
 		if (pkt->off < pkt->len) {
+			/* We are queueing the same virtio_vsock_pkt to handle
+			 * the remaining bytes, and we want to deliver it
+			 * to monitoring devices in the next iteration.
+			 */
+			pkt->tap_delivered = false;
+
 			spin_lock_bh(&vsock->send_pkt_list_lock);
 			list_add(&pkt->list, &vsock->send_pkt_list);
 			spin_unlock_bh(&vsock->send_pkt_list_lock);

include/linux/virtio_vsock.h

@@ -48,6 +48,7 @@ struct virtio_vsock_pkt {
 	u32 len;
 	u32 off;
 	bool reply;
+	bool tap_delivered;
 };
 
 struct virtio_vsock_pkt_info {

net/vmw_vsock/virtio_transport_common.c

@@ -157,7 +157,11 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque)
 
 void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
 {
+	if (pkt->tap_delivered)
+		return;
+
 	vsock_deliver_tap(virtio_transport_build_skb, pkt);
+	pkt->tap_delivered = true;
 }
 EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);