On Thu, Nov 21, 2019 at 10:59:48AM +0100, Stefano Garzarella wrote: > On Thu, Nov 21, 2019 at 09:34:58AM +0000, Stefan Hajnoczi wrote: > > On Tue, Nov 19, 2019 at 12:01:19PM +0100, Stefano Garzarella wrote: > > > > Ideas for long-term changes below. > > > > Reviewed-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx> > > > > Thanks for reviewing! > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > > index 760049454a23..c2a3dc3113ba 100644 > > > --- a/MAINTAINERS > > > +++ b/MAINTAINERS > > > @@ -17239,6 +17239,7 @@ F: net/vmw_vsock/diag.c > > > F: net/vmw_vsock/af_vsock_tap.c > > > F: net/vmw_vsock/virtio_transport_common.c > > > F: net/vmw_vsock/virtio_transport.c > > > +F: net/vmw_vsock/vsock_loopback.c > > > F: drivers/net/vsockmon.c > > > F: drivers/vhost/vsock.c > > > F: tools/testing/vsock/ > > > > At this point you are most active in virtio-vsock and I am reviewing > > patches on a best-effort basis. Feel free to add yourself as > > maintainer. > > > > Sure, I'd be happy to maintain it. > > > > diff --git a/net/vmw_vsock/vsock_loopback.c b/net/vmw_vsock/vsock_loopback.c > > > new file mode 100644 > > > index 000000000000..3d1c1a88305f > > > --- /dev/null > > > +++ b/net/vmw_vsock/vsock_loopback.c > > > @@ -0,0 +1,217 @@ > > > +// SPDX-License-Identifier: GPL-2.0-only > > > +/* > > > + * loopback transport for vsock using virtio_transport_common APIs > > > + * > > > + * Copyright (C) 2013-2019 Red Hat, Inc. > > > + * Author: Asias He <asias@xxxxxxxxxx> > > > + * Stefan Hajnoczi <stefanha@xxxxxxxxxx> > > > + * Stefano Garzarella <sgarzare@xxxxxxxxxx> > > > + * > > > + */ > > > +#include <linux/spinlock.h> > > > +#include <linux/module.h> > > > +#include <linux/list.h> > > > +#include <linux/virtio_vsock.h> > > > > Is it time to rename the generic functionality in > > virtio_transport_common.c? This doesn't have anything to do with virtio > > :). > > > > Completely agree, new transports could use it to handle the protocol without > reimplementing things already done. > > > > + > > > +static struct workqueue_struct *vsock_loopback_workqueue; > > > +static struct vsock_loopback *the_vsock_loopback; > > > > the_vsock_loopback could be a static global variable (not a pointer) and > > vsock_loopback_workqueue could also be included in the struct. > > > > The RCU pointer is really a way to synchronize vsock_loopback_send_pkt() > > and vsock_loopback_cancel_pkt() with module exit. There is no other > > reason for using a pointer. > > > > It's cleaner to implement the synchronization once in af_vsock.c (or > > virtio_transport_common.c) instead of making each transport do it. > > Maybe try_module_get() and related APIs provide the necessary semantics > > so that core vsock code can hold the transport module while it's being > > used to send/cancel a packet. > > Right, the module cannot be unloaded until open sockets, so here the > synchronization is not needed. > > The synchronization come from virtio-vsock device that can be > hot-unplugged while sockets are still open, but that can't happen here. > > I will remove the pointers and RCU in the v2. > > Can I keep your R-b or do you prefer to watch v2 first? > > > > > > +MODULE_ALIAS_NETPROTO(PF_VSOCK); > > > > Why does this module define the alias for PF_VSOCK? Doesn't another > > module already define this alias? > > It is a way to load this module when PF_VSOCK is starting to be used. > MODULE_ALIAS_NETPROTO(PF_VSOCK) is already defined in vmci_transport > and hyperv_transport. IIUC it is used for the same reason. > > In virtio_transport we don't need it because it will be loaded when > the PCI device is discovered. > > Do you think there's a better way? > Should I include the vsock_loopback transport directly in af_vsock > without creating a new module? > That last thing I said may not be possible: I remembered that I tried, 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. Do you think it's okay in this case to keep MODULE_ALIAS_NETPROTO(PF_VSOCK) or is there a better way? Thanks, Stefano _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
