[Patch net] vsock: improve tap delivery accuracy

[Cong Wang <xiyou.wangcong@gmail.com>]

From: Cong Wang <cong.wang@bytedance.com>

When virtqueue_add_sgs() fails, the skb is put back to send queue,
we should not deliver the copy to tap device in this case. So we
need to move virtio_transport_deliver_tap_pkt() down after all
possible failures.

Fixes: 82dfb540aeb2 ("VSOCK: Add virtio vsock vsockmon hooks")
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Stefano Garzarella <sgarzare@redhat.com>
Cc: Bobby Eshleman <bobby.eshleman@bytedance.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
---
 net/vmw_vsock/virtio_transport.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index e95df847176b..055678628c07 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -109,9 +109,6 @@ virtio_transport_send_pkt_work(struct work_struct *work)
 		if (!skb)
 			break;
 
-		virtio_transport_deliver_tap_pkt(skb);
-		reply = virtio_vsock_skb_reply(skb);
-
 		sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb)));
 		sgs[out_sg++] = &hdr;
 		if (skb->len > 0) {
@@ -128,6 +125,8 @@ virtio_transport_send_pkt_work(struct work_struct *work)
 			break;
 		}
 
+		virtio_transport_deliver_tap_pkt(skb);
+		reply = virtio_vsock_skb_reply(skb);
 		if (reply) {
 			struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX];
 			int val;
-- 
2.34.1