nfp: don't depend on eth_tbl being available

For very very old generation of the management FW Ethernet port
information table may theoretically not be available.  This in
turn will cause the nfp_port structures to not be allocated.

Make sure we don't crash the kernel when there is no eth_tbl:

RIP: 0010:nfp_net_pci_probe+0xf2/0xb40 [nfp]
...
Call Trace:
  nfp_pci_probe+0x6de/0xab0 [nfp]
  local_pci_probe+0x47/0xa0
  work_for_cpu_fn+0x1a/0x30
  process_one_work+0x1de/0x3e0

Found while working with broken/development version of management FW.

Fixes: a5950182 ("nfp: map mac_stats and vf_cfg BARs")
Fixes: 93da7d96 ("nfp: provide nfp_port to of nfp_net_get_mac_addr()")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Dirk van der Merwe <dirk.vandermerwe@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/flower/main.c

@@ -360,7 +360,7 @@ nfp_flower_spawn_phy_reprs(struct nfp_app *app, struct nfp_flower_priv *priv)
 		}
 
 		SET_NETDEV_DEV(repr, &priv->nn->pdev->dev);
-		nfp_net_get_mac_addr(app->pf, port);
+		nfp_net_get_mac_addr(app->pf, repr, port);
 
 		cmsg_port_id = nfp_flower_cmsg_phys_port(phys_port);
 		err = nfp_repr_init(app, repr,

drivers/net/ethernet/netronome/nfp/nfp_app_nic.c

@@ -69,7 +69,7 @@ int nfp_app_nic_vnic_alloc(struct nfp_app *app, struct nfp_net *nn,
 	if (err)
 		return err < 0 ? err : 0;
 
-	nfp_net_get_mac_addr(app->pf, nn->port);
+	nfp_net_get_mac_addr(app->pf, nn->dp.netdev, nn->port);
 
 	return 0;
 }

drivers/net/ethernet/netronome/nfp/nfp_main.h

@@ -171,7 +171,9 @@ void nfp_net_pci_remove(struct nfp_pf *pf);
 int nfp_hwmon_register(struct nfp_pf *pf);
 void nfp_hwmon_unregister(struct nfp_pf *pf);
 
-void nfp_net_get_mac_addr(struct nfp_pf *pf, struct nfp_port *port);
+void
+nfp_net_get_mac_addr(struct nfp_pf *pf, struct net_device *netdev,
+		     struct nfp_port *port);
 
 bool nfp_ctrl_tx(struct nfp_net *nn, struct sk_buff *skb);
 

drivers/net/ethernet/netronome/nfp/nfp_net_main.c

@@ -67,23 +67,26 @@
 /**
  * nfp_net_get_mac_addr() - Get the MAC address.
  * @pf:       NFP PF handle
+ * @netdev:   net_device to set MAC address on
  * @port:     NFP port structure
  *
  * First try to get the MAC address from NSP ETH table. If that
  * fails generate a random address.
  */
-void nfp_net_get_mac_addr(struct nfp_pf *pf, struct nfp_port *port)
+void
+nfp_net_get_mac_addr(struct nfp_pf *pf, struct net_device *netdev,
+		     struct nfp_port *port)
 {
 	struct nfp_eth_table_port *eth_port;
 
 	eth_port = __nfp_port_get_eth_port(port);
 	if (!eth_port) {
-		eth_hw_addr_random(port->netdev);
+		eth_hw_addr_random(netdev);
 		return;
 	}
 
-	ether_addr_copy(port->netdev->dev_addr, eth_port->mac_addr);
-	ether_addr_copy(port->netdev->perm_addr, eth_port->mac_addr);
+	ether_addr_copy(netdev->dev_addr, eth_port->mac_addr);
+	ether_addr_copy(netdev->perm_addr, eth_port->mac_addr);
 }
 
 static struct nfp_eth_table_port *
@@ -511,6 +514,7 @@ static int nfp_net_pci_map_mem(struct nfp_pf *pf)
 		return PTR_ERR(mem);
 	}
 
+	if (pf->eth_tbl) {
 		min_size =  NFP_MAC_STATS_SIZE * (pf->eth_tbl->max_index + 1);
 		pf->mac_stats_mem = nfp_rtsym_map(pf->rtbl, "_mac_stats",
 						  "net.macstats", min_size,
@@ -522,6 +526,7 @@ static int nfp_net_pci_map_mem(struct nfp_pf *pf)
 			}
 			pf->mac_stats_mem = NULL;
 		}
+	}
 
 	pf->vf_cfg_mem = nfp_net_pf_map_rtsym(pf, "net.vfcfg",
 					      "_pf%d_net_vf_bar",