vhost/vsock: fix packet delivery order to monitoring devices

[ Upstream commit 107bc0766b9feb5113074c753735a3f115c2141f ]

We want to deliver packets to monitoring devices before it is
put in the virtqueue, to avoid that replies can appear in the
packet capture before the transmitted packet.
Signed-off-by: NStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NSasha Levin <sashal@kernel.org>

drivers/vhost/vsock.c

@@ -182,14 +182,14 @@ 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;