Re: [RFC PATCH v9 12/19] virtio/vsock: add SEQPACKET receive logic

From: Stefano Garzarella <sgarzare@redhat.com>
To: Arseny Krasnov <arseny.krasnov@kaspersky.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Jason Wang <jasowang@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Jorgen Hansen <jhansen@vmware.com>,
	Andra Paraschiv <andraprs@amazon.com>,
	Norbert Slusarek <nslusarek@gmx.net>,
	Colin Ian King <colin.king@canonical.com>,
	kvm@vger.kernel.org, virtualization@lists.linux-foundation.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	stsp2@yandex.ru, oxffffaa@gmail.com
Subject: Re: [RFC PATCH v9 12/19] virtio/vsock: add SEQPACKET receive logic
Date: Thu, 13 May 2021 14:14:00 +0200	[thread overview]
Message-ID: <20210513121400.7u7kectkxwame76b@steredhat> (raw)
In-Reply-To: <20210508163544.3432132-1-arseny.krasnov@kaspersky.com>

On Sat, May 08, 2021 at 07:35:40PM +0300, Arseny Krasnov wrote:
>This modifies current receive logic for SEQPACKET support:
>1) Inserts 'RW' packet to socket's rx queue, but without merging with
>   buffer of last packet in queue.

This is not true anymore, right?

>2) Performs check for packet and socket types on receive(if mismatch,
>   then reset connection).
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

Also this patch is changed :-)

>---
> net/vmw_vsock/virtio_transport_common.c | 28 +++++++++++++++++++++++--
> 1 file changed, 26 insertions(+), 2 deletions(-)
>
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index f649a21dd23b..7fea0a2192f7 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -165,6 +165,14 @@ void virtio_transport_deliver_tap_pkt(struct virtio_vsock_pkt *pkt)
> }
> EXPORT_SYMBOL_GPL(virtio_transport_deliver_tap_pkt);
>
>+static u16 virtio_transport_get_type(struct sock *sk)
>+{
>+	if (sk->sk_type == SOCK_STREAM)
>+		return VIRTIO_VSOCK_TYPE_STREAM;
>+	else
>+		return VIRTIO_VSOCK_TYPE_SEQPACKET;
>+}
>+
> /* This function can only be used on connecting/connected sockets,
>  * since a socket assigned to a transport is required.
>  *
>@@ -980,11 +988,15 @@ virtio_transport_recv_enqueue(struct vsock_sock *vsk,
> 		/* If there is space in the last packet queued, we copy the
> 		 * new packet in its buffer.
> 		 */
>-		if (pkt->len <= last_pkt->buf_len - last_pkt->len) {
>+		if ((pkt->len <= last_pkt->buf_len - last_pkt->len) &&
>+		    !(le32_to_cpu(last_pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR)) {

Maybe we should update the comment above.

> 			memcpy(last_pkt->buf + last_pkt->len, pkt->buf,
> 			       pkt->len);
> 			last_pkt->len += pkt->len;
> 			free_pkt = true;
>+
>+			if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR)
>+				last_pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);

What about doing the following in any case?

			last_pkt->hdr.flags |= pkt->hdr.flags;

> 			goto out;
> 		}
> 	}