Merge branch 'net-inline-rollback_registered-functions'

After recent changes to the error path of register_netdevice()
we no longer need a version of unregister_netdevice_many() which
does not set net_todo. We can inline the rollback_registered()
functions into respective unregister_netdevice() calls.

Link: https://lore.kernel.org/r/20210119202521.3108236-1-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/core/dev.c

@@ -5709,7 +5709,7 @@ static void flush_all_backlogs(void)
 	}
 
 	/* we can have in flight packet[s] on the cpus we are not flushing,
-	 * synchronize_net() in rollback_registered_many() will take care of
+	 * synchronize_net() in unregister_netdevice_many() will take care of
 	 * them
 	 */
 	for_each_cpu(cpu, &flush_cpus)
@@ -9459,106 +9459,6 @@ static void net_set_todo(struct net_device *dev)
 	dev_net(dev)->dev_unreg_count++;
 }
 
-static void rollback_registered_many(struct list_head *head)
-{
-	struct net_device *dev, *tmp;
-	LIST_HEAD(close_head);
-
-	BUG_ON(dev_boot_phase);
-	ASSERT_RTNL();
-
-	list_for_each_entry_safe(dev, tmp, head, unreg_list) {
-		/* Some devices call without registering
-		 * for initialization unwind. Remove those
-		 * devices and proceed with the remaining.
-		 */
-		if (dev->reg_state == NETREG_UNINITIALIZED) {
-			pr_debug("unregister_netdevice: device %s/%p never was registered\n",
-				 dev->name, dev);
-
-			WARN_ON(1);
-			list_del(&dev->unreg_list);
-			continue;
-		}
-		dev->dismantle = true;
-		BUG_ON(dev->reg_state != NETREG_REGISTERED);
-	}
-
-	/* If device is running, close it first. */
-	list_for_each_entry(dev, head, unreg_list)
-		list_add_tail(&dev->close_list, &close_head);
-	dev_close_many(&close_head, true);
-
-	list_for_each_entry(dev, head, unreg_list) {
-		/* And unlink it from device chain. */
-		unlist_netdevice(dev);
-
-		dev->reg_state = NETREG_UNREGISTERING;
-	}
-	flush_all_backlogs();
-
-	synchronize_net();
-
-	list_for_each_entry(dev, head, unreg_list) {
-		struct sk_buff *skb = NULL;
-
-		/* Shutdown queueing discipline. */
-		dev_shutdown(dev);
-
-		dev_xdp_uninstall(dev);
-
-		/* Notify protocols, that we are about to destroy
-		 * this device. They should clean all the things.
-		 */
-		call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
-
-		if (!dev->rtnl_link_ops ||
-		    dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
-			skb = rtmsg_ifinfo_build_skb(RTM_DELLINK, dev, ~0U, 0,
-						     GFP_KERNEL, NULL, 0);
-
-		/*
-		 *	Flush the unicast and multicast chains
-		 */
-		dev_uc_flush(dev);
-		dev_mc_flush(dev);
-
-		netdev_name_node_alt_flush(dev);
-		netdev_name_node_free(dev->name_node);
-
-		if (dev->netdev_ops->ndo_uninit)
-			dev->netdev_ops->ndo_uninit(dev);
-
-		if (skb)
-			rtmsg_ifinfo_send(skb, dev, GFP_KERNEL);
-
-		/* Notifier chain MUST detach us all upper devices. */
-		WARN_ON(netdev_has_any_upper_dev(dev));
-		WARN_ON(netdev_has_any_lower_dev(dev));
-
-		/* Remove entries from kobject tree */
-		netdev_unregister_kobject(dev);
-#ifdef CONFIG_XPS
-		/* Remove XPS queueing entries */
-		netif_reset_xps_queues_gt(dev, 0);
-#endif
-	}
-
-	synchronize_net();
-
-	list_for_each_entry(dev, head, unreg_list)
-		dev_put(dev);
-}
-
-static void rollback_registered(struct net_device *dev)
-{
-	LIST_HEAD(single);
-
-	list_add(&dev->unreg_list, &single);
-	rollback_registered_many(&single);
-	list_del(&single);
-}
-
 static netdev_features_t netdev_sync_upper_features(struct net_device *lower,
 	struct net_device *upper, netdev_features_t features)
 {
@@ -10108,8 +10008,7 @@ int register_netdevice(struct net_device *dev)
 	if (ret) {
 		/* Expect explicit free_netdev() on failure */
 		dev->needs_free_netdev = false;
-		rollback_registered(dev);
-		net_set_todo(dev);
+		unregister_netdevice_queue(dev, NULL);
 		goto out;
 	}
 	/*
@@ -10731,9 +10630,10 @@ void unregister_netdevice_queue(struct net_device *dev, struct list_head *head)
 	if (head) {
 		list_move_tail(&dev->unreg_list, head);
 	} else {
-		rollback_registered(dev);
-		/* Finish processing unregister after unlock */
-		net_set_todo(dev);
+		LIST_HEAD(single);
+
+		list_add(&dev->unreg_list, &single);
+		unregister_netdevice_many(&single);
 	}
 }
 EXPORT_SYMBOL(unregister_netdevice_queue);
@@ -10747,14 +10647,100 @@ EXPORT_SYMBOL(unregister_netdevice_queue);
  */
 void unregister_netdevice_many(struct list_head *head)
 {
-	struct net_device *dev;
+	struct net_device *dev, *tmp;
+	LIST_HEAD(close_head);
+
+	BUG_ON(dev_boot_phase);
+	ASSERT_RTNL();
+
+	if (list_empty(head))
+		return;
+
+	list_for_each_entry_safe(dev, tmp, head, unreg_list) {
+		/* Some devices call without registering
+		 * for initialization unwind. Remove those
+		 * devices and proceed with the remaining.
+		 */
+		if (dev->reg_state == NETREG_UNINITIALIZED) {
+			pr_debug("unregister_netdevice: device %s/%p never was registered\n",
+				 dev->name, dev);
+
+			WARN_ON(1);
+			list_del(&dev->unreg_list);
+			continue;
+		}
+		dev->dismantle = true;
+		BUG_ON(dev->reg_state != NETREG_REGISTERED);
+	}
+
+	/* If device is running, close it first. */
+	list_for_each_entry(dev, head, unreg_list)
+		list_add_tail(&dev->close_list, &close_head);
+	dev_close_many(&close_head, true);
+
+	list_for_each_entry(dev, head, unreg_list) {
+		/* And unlink it from device chain. */
+		unlist_netdevice(dev);
+
+		dev->reg_state = NETREG_UNREGISTERING;
+	}
+	flush_all_backlogs();
+
+	synchronize_net();
+
+	list_for_each_entry(dev, head, unreg_list) {
+		struct sk_buff *skb = NULL;
 
-	if (!list_empty(head)) {
-		rollback_registered_many(head);
-		list_for_each_entry(dev, head, unreg_list)
-			net_set_todo(dev);
-		list_del(head);
+		/* Shutdown queueing discipline. */
+		dev_shutdown(dev);
+
+		dev_xdp_uninstall(dev);
+
+		/* Notify protocols, that we are about to destroy
+		 * this device. They should clean all the things.
+		 */
+		call_netdevice_notifiers(NETDEV_UNREGISTER, dev);
+
+		if (!dev->rtnl_link_ops ||
+		    dev->rtnl_link_state == RTNL_LINK_INITIALIZED)
+			skb = rtmsg_ifinfo_build_skb(RTM_DELLINK, dev, ~0U, 0,
+						     GFP_KERNEL, NULL, 0);
+
+		/*
+		 *	Flush the unicast and multicast chains
+		 */
+		dev_uc_flush(dev);
+		dev_mc_flush(dev);
+
+		netdev_name_node_alt_flush(dev);
+		netdev_name_node_free(dev->name_node);
+
+		if (dev->netdev_ops->ndo_uninit)
+			dev->netdev_ops->ndo_uninit(dev);
+
+		if (skb)
+			rtmsg_ifinfo_send(skb, dev, GFP_KERNEL);
+
+		/* Notifier chain MUST detach us all upper devices. */
+		WARN_ON(netdev_has_any_upper_dev(dev));
+		WARN_ON(netdev_has_any_lower_dev(dev));
+
+		/* Remove entries from kobject tree */
+		netdev_unregister_kobject(dev);
+#ifdef CONFIG_XPS
+		/* Remove XPS queueing entries */
+		netif_reset_xps_queues_gt(dev, 0);
+#endif
+	}
+
+	synchronize_net();
+
+	list_for_each_entry(dev, head, unreg_list) {
+		dev_put(dev);
+		net_set_todo(dev);
 	}
+
+	list_del(head);
 }
 EXPORT_SYMBOL(unregister_netdevice_many);