Date:   Mon, 6 Mar 2023 13:08:57 +0100
From:   Stefano Garzarella <sgarzare@redhat.com>
To:     Arseniy Krasnov <avkrasnov@sberdevices.ru>
Cc:     Stefan Hajnoczi <stefanha@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Bobby Eshleman <bobby.eshleman@bytedance.com>,
        kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel@sberdevices.ru, oxffffaa@gmail.com
Subject: Re: [RFC PATCH v2 2/4] virtio/vsock: remove all data from sk_buff
Message-ID: <20230306120857.6flftb3fftmsceyl@sgarzare-redhat>
References: <a7ab414b-5e41-c7b6-250b-e8401f335859@sberdevices.ru>
 <dfadea17-a91e-105f-c213-a73f9731c8bd@sberdevices.ru>
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Precedence: bulk

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@sberdevices.ru>
>---
> 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
>