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

[Bobby Eshleman <bobbyeshleman@gmail.com>]

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@bytedance.com>
> > ---
> >  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?

> >  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