> From: Stefano Garzarella [mailto:sgarzare@xxxxxxxxxx] > Sent: Thursday, November 21, 2019 5:13 PM > > On Thu, Nov 21, 2019 at 03:53:47PM +0000, Jorgen Hansen wrote: > > > From: Stefano Garzarella [mailto:sgarzare@xxxxxxxxxx] > > > Sent: Thursday, November 21, 2019 4:22 PM > > > > > > On Thu, Nov 21, 2019 at 03:04:18PM +0000, Jorgen Hansen wrote: > > > > > From: Stefano Garzarella [mailto:sgarzare@xxxxxxxxxx] > > > > > Sent: Tuesday, November 19, 2019 12:01 PM > > > > > To: netdev@xxxxxxxxxxxxxxx > > > > > > > > > > This patch allows to register a transport able to handle > > > > > local communication (loopback). > > > > > > > > > > Signed-off-by: Stefano Garzarella <sgarzare@xxxxxxxxxx> > > > > > --- > > > > > include/net/af_vsock.h | 2 ++ > > > > > net/vmw_vsock/af_vsock.c | 17 ++++++++++++++++- > > > > > 2 files changed, 18 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h > > > > > index 4206dc6d813f..b1c717286993 100644 > > > > > --- a/include/net/af_vsock.h > > > > > +++ b/include/net/af_vsock.h > > > > > @@ -98,6 +98,8 @@ struct vsock_transport_send_notify_data { > > > > > #define VSOCK_TRANSPORT_F_G2H 0x00000002 > > > > > /* Transport provides DGRAM communication */ > > > > > #define VSOCK_TRANSPORT_F_DGRAM 0x00000004 > > > > > +/* Transport provides local (loopback) communication */ > > > > > +#define VSOCK_TRANSPORT_F_LOCAL 0x00000008 > > > > > > > > > > struct vsock_transport { > > > > > struct module *module; > > > > > diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c > > > > > index cc8659838bf2..c9e5bad59dc1 100644 > > > > > --- a/net/vmw_vsock/af_vsock.c > > > > > +++ b/net/vmw_vsock/af_vsock.c > > > > > @@ -136,6 +136,8 @@ static const struct vsock_transport > > > *transport_h2g; > > > > > static const struct vsock_transport *transport_g2h; > > > > > /* Transport used for DGRAM communication */ > > > > > static const struct vsock_transport *transport_dgram; > > > > > +/* Transport used for local communication */ > > > > > +static const struct vsock_transport *transport_local; > > > > > static DEFINE_MUTEX(vsock_register_mutex); > > > > > > > > > > /**** UTILS ****/ > > > > > @@ -2130,7 +2132,7 @@ > > > EXPORT_SYMBOL_GPL(vsock_core_get_transport); > > > > > > > > > > int vsock_core_register(const struct vsock_transport *t, int features) > > > > > { > > > > > - const struct vsock_transport *t_h2g, *t_g2h, *t_dgram; > > > > > + const struct vsock_transport *t_h2g, *t_g2h, *t_dgram, > *t_local; > > > > > int err = mutex_lock_interruptible(&vsock_register_mutex); > > > > > > > > > > if (err) > > > > > @@ -2139,6 +2141,7 @@ int vsock_core_register(const struct > > > > > vsock_transport *t, int features) > > > > > t_h2g = transport_h2g; > > > > > t_g2h = transport_g2h; > > > > > t_dgram = transport_dgram; > > > > > + t_local = transport_local; > > > > > > > > > > if (features & VSOCK_TRANSPORT_F_H2G) { > > > > > if (t_h2g) { > > > > > @@ -2164,9 +2167,18 @@ int vsock_core_register(const struct > > > > > vsock_transport *t, int features) > > > > > t_dgram = t; > > > > > } > > > > > > > > > > + if (features & VSOCK_TRANSPORT_F_LOCAL) { > > > > > + if (t_local) { > > > > > + err = -EBUSY; > > > > > + goto err_busy; > > > > > + } > > > > > + t_local = t; > > > > > + } > > > > > + > > > > > transport_h2g = t_h2g; > > > > > transport_g2h = t_g2h; > > > > > transport_dgram = t_dgram; > > > > > + transport_local = t_local; > > > > > > > > > > err_busy: > > > > > mutex_unlock(&vsock_register_mutex); > > > > > @@ -2187,6 +2199,9 @@ void vsock_core_unregister(const struct > > > > > vsock_transport *t) > > > > > if (transport_dgram == t) > > > > > transport_dgram = NULL; > > > > > > > > > > + if (transport_local == t) > > > > > + transport_local = NULL; > > > > > + > > > > > mutex_unlock(&vsock_register_mutex); > > > > > } > > > > > EXPORT_SYMBOL_GPL(vsock_core_unregister); > > > > > -- > > > > > 2.21.0 > > > > > > > > Having loopback support as a separate transport fits nicely, but do we > need > > > to support > > > > different variants of loopback? It could just be built in. > > > > > > I agree with you, indeed initially I developed it as built in, but > > > DEPMOD found a cyclic dependency because vsock_transport use > > > virtio_transport_common that use vsock, so if I include vsock_transport > > > in the vsock module, DEPMOD is not happy. > > > > > > I don't know how to break this cyclic dependency, do you have any ideas? > > > > One way to view this would be that the loopback transport and the support > > it uses from virtio_transport_common are independent of virtio as such, > > and could be part of the af_vsock module if loopback is configured. So > > in a way, the virtio g2h and h2g transports would be extensions of the > > built in loopback transport. But that brings in quite a bit of code so > > it could be better to just keep it as is. > > Great idea! > > Stefan already suggested (as a long-term goal) to rename the generic > functionality in virtio_transport_common.c > > Maybe I can do both in another series later on, since it requires enough > changes. Sounds good to me. Thanks, Jorgen
