Re: [PATCH net-next v6 3/8] net/funeth: probing and netdev ops

[Dimitris Michailidis <d.michailidis@fungible.com>]

On Wed, Jan 12, 2022 at 2:45 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Sun,  9 Jan 2022 17:56:31 -0800 Dimitris Michailidis wrote:
> > +static void fun_update_link_state(const struct fun_ethdev *ed,
> > +                               const struct fun_admin_port_notif *notif)
> > +{
> > +     unsigned int port_idx = be16_to_cpu(notif->id);
> > +     struct net_device *netdev;
> > +     struct funeth_priv *fp;
> > +
> > +     if (port_idx >= ed->num_ports)
> > +             return;
> > +
> > +     netdev = ed->netdevs[port_idx];
> > +     fp = netdev_priv(netdev);
> > +
> > +     write_seqcount_begin(&fp->link_seq);
> > +     fp->link_speed = be32_to_cpu(notif->speed) * 10;  /* 10 Mbps->Mbps */
> > +     fp->active_fc = notif->flow_ctrl;
> > +     fp->active_fec = notif->fec;
> > +     fp->xcvr_type = notif->xcvr_type;
> > +     fp->link_down_reason = notif->link_down_reason;
> > +     fp->lp_advertising = be64_to_cpu(notif->lp_advertising);
> > +
> > +     if ((notif->link_state | notif->missed_events) & FUN_PORT_FLAG_MAC_DOWN)
> > +             netif_carrier_off(netdev);
> > +     if (notif->link_state & FUN_PORT_FLAG_MAC_UP)
> > +             netif_carrier_on(netdev);
> > +
> > +     write_seqcount_end(&fp->link_seq);
> > +     fun_report_link(netdev);
> > +}
> > +
> > +/* handler for async events delivered through the admin CQ */
> > +static void fun_event_cb(struct fun_dev *fdev, void *entry)
> > +{
> > +     u8 op = ((struct fun_admin_rsp_common *)entry)->op;
> > +
> > +     if (op == FUN_ADMIN_OP_PORT) {
> > +             const struct fun_admin_port_notif *rsp = entry;
> > +
> > +             if (rsp->subop == FUN_ADMIN_SUBOP_NOTIFY) {
> > +                     fun_update_link_state(to_fun_ethdev(fdev), rsp);
>
> Is there locking between service task and admin queue events?

There isn't any lock between them. They coordinate through atomic
bitops and the synchronization work_structs provide.