Re: [PATCH RFC net-next v5 13/14] virtio/vsock: implement datagram support

[Arseniy Krasnov]

On 26.07.2023 20:58, Bobby Eshleman wrote:
> On Sat, Jul 22, 2023 at 11:45:29AM +0300, Arseniy Krasnov wrote:
>>
>>
>> On 19.07.2023 03:50, Bobby Eshleman wrote:
>>> This commit implements datagram support for virtio/vsock by teaching
>>> virtio to use the general virtio transport ->dgram_addr_init() function
>>> and implementation a new version of ->dgram_allow().
>>>
>>> Additionally, it drops virtio_transport_dgram_allow() as an exported
>>> symbol because it is no longer used in other transports.
>>>
>>> Signed-off-by: Bobby Eshleman <bobby.eshleman@xxxxxxxxxxxxx>
>>> ---
>>>  include/linux/virtio_vsock.h            |  1 -
>>>  net/vmw_vsock/virtio_transport.c        | 24 +++++++++++++++++++++++-
>>>  net/vmw_vsock/virtio_transport_common.c |  6 ------
>>>  3 files changed, 23 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>>> index b3856b8a42b3..d0a4f08b12c1 100644
>>> --- a/include/linux/virtio_vsock.h
>>> +++ b/include/linux/virtio_vsock.h
>>> @@ -211,7 +211,6 @@ void virtio_transport_notify_buffer_size(struct vsock_sock *vsk, u64 *val);
>>>  u64 virtio_transport_stream_rcvhiwat(struct vsock_sock *vsk);
>>>  bool virtio_transport_stream_is_active(struct vsock_sock *vsk);
>>>  bool virtio_transport_stream_allow(u32 cid, u32 port);
>>> -bool virtio_transport_dgram_allow(u32 cid, u32 port);
>>>  void virtio_transport_dgram_addr_init(struct sk_buff *skb,
>>>  				      struct sockaddr_vm *addr);
>>>  
>>> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>>> index ac2126c7dac5..713718861bd4 100644
>>> --- a/net/vmw_vsock/virtio_transport.c
>>> +++ b/net/vmw_vsock/virtio_transport.c
>>> @@ -63,6 +63,7 @@ struct virtio_vsock {
>>>  
>>>  	u32 guest_cid;
>>>  	bool seqpacket_allow;
>>> +	bool dgram_allow;
>>>  };
>>>  
>>>  static u32 virtio_transport_get_local_cid(void)
>>> @@ -413,6 +414,7 @@ static void virtio_vsock_rx_done(struct virtqueue *vq)
>>>  	queue_work(virtio_vsock_workqueue, &vsock->rx_work);
>>>  }
>>>  
>>> +static bool virtio_transport_dgram_allow(u32 cid, u32 port);
>>
>> May be add body here? Without prototyping? Same for loopback and vhost.
>>
> 
> Sounds okay with me, but this seems to go against the pattern
> established by seqpacket. Any reason why?

Stefano Garzarella <sgarzare@xxxxxxxxxx> commented my patch with the same approach:

https://lore.kernel.org/netdev/lex6l5suez7azhirt22lidndtjomkbagfbpvvi5p7c2t7klzas@4l2qly7at37c/

Thanks, Arseniy


> 
>>>  static bool virtio_transport_seqpacket_allow(u32 remote_cid);
>>>  
>>>  static struct virtio_transport virtio_transport = {
>>> @@ -430,6 +432,7 @@ static struct virtio_transport virtio_transport = {
>>>  
>>>  		.dgram_enqueue            = virtio_transport_dgram_enqueue,
>>>  		.dgram_allow              = virtio_transport_dgram_allow,
>>> +		.dgram_addr_init          = virtio_transport_dgram_addr_init,
>>>  
>>>  		.stream_dequeue           = virtio_transport_stream_dequeue,
>>>  		.stream_enqueue           = virtio_transport_stream_enqueue,
>>> @@ -462,6 +465,21 @@ static struct virtio_transport virtio_transport = {
>>>  	.send_pkt = virtio_transport_send_pkt,
>>>  };
>>>  
>>> +static bool virtio_transport_dgram_allow(u32 cid, u32 port)
>>> +{
>>> +	struct virtio_vsock *vsock;
>>> +	bool dgram_allow;
>>> +
>>> +	dgram_allow = false;
>>> +	rcu_read_lock();
>>> +	vsock = rcu_dereference(the_virtio_vsock);
>>> +	if (vsock)
>>> +		dgram_allow = vsock->dgram_allow;
>>> +	rcu_read_unlock();
>>> +
>>> +	return dgram_allow;
>>> +}
>>> +
>>>  static bool virtio_transport_seqpacket_allow(u32 remote_cid)
>>>  {
>>>  	struct virtio_vsock *vsock;
>>> @@ -655,6 +673,9 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
>>>  	if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_SEQPACKET))
>>>  		vsock->seqpacket_allow = true;
>>>  
>>> +	if (virtio_has_feature(vdev, VIRTIO_VSOCK_F_DGRAM))
>>> +		vsock->dgram_allow = true;
>>> +
>>>  	vdev->priv = vsock;
>>>  
>>>  	ret = virtio_vsock_vqs_init(vsock);
>>> @@ -747,7 +768,8 @@ static struct virtio_device_id id_table[] = {
>>>  };
>>>  
>>>  static unsigned int features[] = {
>>> -	VIRTIO_VSOCK_F_SEQPACKET
>>> +	VIRTIO_VSOCK_F_SEQPACKET,
>>> +	VIRTIO_VSOCK_F_DGRAM
>>>  };
>>>  
>>>  static struct virtio_driver virtio_vsock_driver = {
>>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>>> index 96118e258097..77898f5325cd 100644
>>> --- a/net/vmw_vsock/virtio_transport_common.c
>>> +++ b/net/vmw_vsock/virtio_transport_common.c
>>> @@ -783,12 +783,6 @@ bool virtio_transport_stream_allow(u32 cid, u32 port)
>>>  }
>>>  EXPORT_SYMBOL_GPL(virtio_transport_stream_allow);
>>>  
>>> -bool virtio_transport_dgram_allow(u32 cid, u32 port)
>>> -{
>>> -	return false;
>>> -}
>>> -EXPORT_SYMBOL_GPL(virtio_transport_dgram_allow);
>>> -
>>>  int virtio_transport_connect(struct vsock_sock *vsk)
>>>  {
>>>  	struct virtio_vsock_pkt_info info = {
>>>
>>
>> Thanks, Arseniy
> 
> Thanks,
> Bobby