Re: [PATCH net-next v2 3/7] nfp: register devlink ports of all reprs

Jakub Kicinski
2019-03-02T19:07:31Z

On Sat, 2 Mar 2019 09:43:47 +0100, Jiri Pirko wrote:
> Fri, Mar 01, 2019 at 07:04:49PM CET, jakub.kicinski@netronome.com wrote:
> >Register all representors as devlink ports.
> >
> >The port_index is slightly tricky to figure out, we use a bit of
> >arbitrary math to create unique IDs for PCI ports.
> >
> >Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> >---
> > .../net/ethernet/netronome/nfp/nfp_devlink.c | 40 ++++++++++++++++++-
> > .../net/ethernet/netronome/nfp/nfp_net_repr.c | 16 +++++++-
> > 2 files changed, 53 insertions(+), 3 deletions(-)
> >
> >diff --git a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
> >index 9af3cb1f2f17..bf7fd9614152 100644
> >--- a/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
> >+++ b/drivers/net/ethernet/netronome/nfp/nfp_devlink.c
> >@@ -350,7 +350,8 @@ const struct devlink_ops nfp_devlink_ops = {
> > .flash_update = nfp_devlink_flash_update,
> > };
> >
> >-int nfp_devlink_port_init(struct nfp_app *app, struct nfp_port *port)
> >+static int
> >+nfp_devlink_port_init_phys(struct devlink *devlink, struct nfp_port *port)
> > {
> > struct nfp_eth_table_port eth_port;
> > int ret;
> >@@ -368,6 +369,27 @@ int nfp_devlink_port_init(struct nfp_app *app, struct nfp_port *port)
> > return 0;
> > }
> >
> >+int nfp_devlink_port_init(struct nfp_app *app, struct nfp_port *port)
> >+{
> >+ struct devlink *devlink = priv_to_devlink(app->pf);
> >+
> >+ switch (port->type) {
> >+ case NFP_PORT_PHYS_PORT:
> >+ return nfp_devlink_port_init_phys(devlink, port);
> >+ case NFP_PORT_PF_PORT:
> >+ devlink_port_type_eth_set(&port->dl_port, port->netdev);
> >+ devlink_port_attrs_pci_pf_set(&port->dl_port, port->pf_id);
> >+ return 0;
> >+ case NFP_PORT_VF_PORT:
> >+ devlink_port_type_eth_set(&port->dl_port, port->netdev);
> >+ devlink_port_attrs_pci_vf_set(&port->dl_port, port->pf_id,
> >+ port->vf_id);
>
> What is the reason to expose vf/pf id for switch port? Isn't it rather
> an attribute of a peer?

Naw, its an attribute of the port. I leave the ASIC via PF n or VF m
of PF n. Whatever is on the other side is isolated from the topology
of the ASIC.

Is the physical port ID an attribute of the other end of the cable?

> >+ return 0;
> >+ default:
> >+ return -EINVAL;
> >+ }
> >+}
> >+
> > void nfp_devlink_port_clean(struct nfp_port *port)
> > {
> > }
> >@@ -376,7 +398,21 @@ int nfp_devlink_port_register(struct nfp_app *app, struct nfp_port *port)
> > {
> > struct devlink *devlink = priv_to_devlink(app->pf);
> >
> >- return devlink_port_register(devlink, &port->dl_port, port->eth_id);
> >+ switch (port->type) {
> >+ case NFP_PORT_PHYS_PORT:
> >+ return devlink_port_register(devlink, &port->dl_port,
> >+ port->eth_id);
> >+ case NFP_PORT_PF_PORT:
> >+ return devlink_port_register(devlink, &port->dl_port,
> >+ (port->pf_id + 1) * 10000 +
> >+ port->pf_split_id * 1000);
>
> Wait. What this 10000/1000 magic about?

port_index has to be unique, I need some unique number here, as I
stated both in the commit message and the cover letter, this is
arbitrary.

I can put the datapath port identifier in there but its (a)
meaningless, (b) a bitfield, so it will look like 8972367083. And it
may change depending on the FW load, so its not stable either.

> >+ case NFP_PORT_VF_PORT:
> >+ return devlink_port_register(devlink, &port->dl_port,
> >+ (port->pf_id + 1) * 10000 +
> >+ port->vf_id + 1);
> >+ default:
> >+ return -EINVAL;
> >+ }
> > }
> >
> > void nfp_devlink_port_unregister(struct nfp_port *port)
> >diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
> >index d2c803bb4e56..869d22760a6e 100644
> >--- a/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
> >+++ b/drivers/net/ethernet/netronome/nfp/nfp_net_repr.c
> >@@ -292,7 +292,9 @@ nfp_repr_transfer_features(struct net_device *netdev, struct net_device *lower)
> >
> > static void nfp_repr_clean(struct nfp_repr *repr)
> > {
> >+ nfp_devlink_port_unregister(repr->port);
> > unregister_netdev(repr->netdev);
> >+ nfp_devlink_port_clean(repr->port);
> > nfp_app_repr_clean(repr->app, repr->netdev);
> > dst_release((struct dst_entry *)repr->dst);
> > nfp_port_free(repr->port);
> >@@ -395,12 +397,24 @@ int nfp_repr_init(struct nfp_app *app, struct net_device *netdev,
> > if (err)
> > goto err_clean;
> >
> >- err = register_netdev(netdev);
> >+ err = nfp_devlink_port_init(app, repr->port);
> > if (err)
> > goto err_repr_clean;
> >
> >+ err = register_netdev(netdev);
> >+ if (err)
> >+ goto err_port_clean;
> >+
> >+ err = nfp_devlink_port_register(app, repr->port);
>
> Don't you want to take my patch ("nfp: register devlink port before
> netdev") to change order of register_netdev and devlink_port_register,
> include it to this patchset before this patch and change the order in
> this patch too? I think it would be clearer to do it from the beginning.

This way both netdev and devlink_port can get registered fully
initialized. Otherwise we'd get two notifications. Are we trying to
establish some ordering rules to get around the rtnl locking? :)

> >+ if (err)
> >+ goto err_unreg_netdev;
> >+
> > return 0;
> >
> >+err_unreg_netdev:
> >+ unregister_netdev(repr->netdev);
> >+err_port_clean:
> >+ nfp_devlink_port_clean(repr->port);
> > err_repr_clean:
> > nfp_app_repr_clean(app, netdev);