Re: [RFC PATCH v2 2/4] virtio/vsock: remove all data from sk_buff

[Stefano Garzarella]

On Sun, Mar 05, 2023 at 11:07:37PM +0300, Arseniy Krasnov wrote:
> In case of SOCK_SEQPACKET all sk_buffs are used once - after read some
> data from it, it will be removed, so user will never read rest of the
> data. Thus we need to update credit parameters of the socket like whole
> sk_buff is read - so call 'skb_pull()' for the whole buffer.
>
> Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff")
> Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
> ---
> net/vmw_vsock/virtio_transport_common.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)

Maybe we could avoid this patch if we directly use pkt_len as I
suggested in the previous patch.

Thanks,
Stefano

> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> index 2e2a773df5c1..30b0539990ba 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -466,7 +466,6 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
> 					dequeued_len = err;
> 				} else {
> 					user_buf_len -= bytes_to_copy;
> -					skb_pull(skb, bytes_to_copy);
> 				}
>
> 				spin_lock_bh(&vvs->rx_lock);
> @@ -484,6 +483,7 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
> 				msg->msg_flags |= MSG_EOR;
> 		}
>
> +		skb_pull(skb, skb->len);
> 		virtio_transport_dec_rx_pkt(vvs, skb);
> 		kfree_skb(skb);
> 	}
> --
> 2.25.1