net: ipa: reorder netdev pointer assignments

Assign the ipa->modem_netdev and endpoint->netdev pointers *before*
registering the network device.  As soon as the device is
registered it can be opened, and by that time we'll want those
pointers valid.

Similarly, don't make those pointers NULL until *after* the modem
network device is unregistered in ipa_modem_stop().

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/ipa_modem.c

@@ -231,13 +231,15 @@ int ipa_modem_start(struct ipa *ipa)
 	SET_NETDEV_DEV(netdev, &ipa->pdev->dev);
 	priv = netdev_priv(netdev);
 	priv->ipa = ipa;
+	ipa->name_map[IPA_ENDPOINT_AP_MODEM_TX]->netdev = netdev;
+	ipa->name_map[IPA_ENDPOINT_AP_MODEM_RX]->netdev = netdev;
+	ipa->modem_netdev = netdev;
 
 	ret = register_netdev(netdev);
-	if (!ret) {
-		ipa->modem_netdev = netdev;
-		ipa->name_map[IPA_ENDPOINT_AP_MODEM_TX]->netdev = netdev;
-		ipa->name_map[IPA_ENDPOINT_AP_MODEM_RX]->netdev = netdev;
-	} else {
+	if (ret) {
+		ipa->modem_netdev = NULL;
+		ipa->name_map[IPA_ENDPOINT_AP_MODEM_RX]->netdev = NULL;
+		ipa->name_map[IPA_ENDPOINT_AP_MODEM_TX]->netdev = NULL;
 		free_netdev(netdev);
 	}
 
@@ -276,10 +278,10 @@ int ipa_modem_stop(struct ipa *ipa)
 		/* If it was opened, stop it first */
 		if (netdev->flags & IFF_UP)
 			(void)ipa_stop(netdev);
+		unregister_netdev(netdev);
+		ipa->modem_netdev = NULL;
 		ipa->name_map[IPA_ENDPOINT_AP_MODEM_RX]->netdev = NULL;
 		ipa->name_map[IPA_ENDPOINT_AP_MODEM_TX]->netdev = NULL;
-		ipa->modem_netdev = NULL;
-		unregister_netdev(netdev);
 		free_netdev(netdev);
 	}