Re: [PATCH v4 5/5] vsock/virtio: change the maximum packet size allowed

From: "Michael S. Tsirkin" <mst@redhat.com>
To: Stefano Garzarella <sgarzare@redhat.com>
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Stefan Hajnoczi <stefanha@redhat.com>,
	"David S. Miller" <davem@davemloft.net>,
	virtualization@lists.linux-foundation.org,
	Jason Wang <jasowang@redhat.com>,
	kvm@vger.kernel.org
Subject: Re: [PATCH v4 5/5] vsock/virtio: change the maximum packet size allowed
Date: Wed, 17 Jul 2019 10:59:52 -0400	[thread overview]
Message-ID: <20190717105703-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20190717113030.163499-6-sgarzare@redhat.com>

On Wed, Jul 17, 2019 at 01:30:30PM +0200, Stefano Garzarella wrote:
> Since now we are able to split packets, we can avoid limiting
> their sizes to VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE.
> Instead, we can use VIRTIO_VSOCK_MAX_PKT_BUF_SIZE as the max
> packet size.
> 
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

OK so this is kind of like GSO where we are passing
64K packets to the vsock and then split at the
low level.

> ---
>  net/vmw_vsock/virtio_transport_common.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
> index 56fab3f03d0e..94cc0fa3e848 100644
> --- a/net/vmw_vsock/virtio_transport_common.c
> +++ b/net/vmw_vsock/virtio_transport_common.c
> @@ -181,8 +181,8 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
>  	vvs = vsk->trans;
>  
>  	/* we can send less than pkt_len bytes */
> -	if (pkt_len > VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE)
> -		pkt_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
> +	if (pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
> +		pkt_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
>  
>  	/* virtio_transport_get_credit might return less than pkt_len credit */
>  	pkt_len = virtio_transport_get_credit(vvs, pkt_len);
> -- 
> 2.20.1