On Wed, Jan 12, 2022 at 2:45 PM Jakub Kicinski [off-list ref] wrote:

On Sun,  9 Jan 2022 17:56:31 -0800 Dimitris Michailidis wrote:

quoted

+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.