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Commit 9bf1907f authored by Eric W. Biederman's avatar Eric W. Biederman Committed by David S. Miller
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macvtap: Rewrite macvtap_newlink so the error handling works. 



Place macvlan_common_newlink at the end of macvtap_newlink because
failing in newlink after registering your network device is not
supported.

Move device_create into a netdevice creation notifier.   The network device
notifier is the only hook that is called after the network device has been
registered with the device layer and before register_network_device returns
success.

Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2259fef0

drivers/net/macvtap.c

+49 −24
Original line number Diff line number Diff line
@@ -280,34 +280,16 @@ static int macvtap_newlink(struct net *src_net, 
			   struct nlattr *tb[],

			   struct nlattr *data[])

{

	struct device *classdev;

	dev_t devt;

	int err;



	err = macvlan_common_newlink(src_net, dev, tb, data,

	/* Don't put anything that may fail after macvlan_common_newlink

	 * because we can't undo what it does.

	 */

	return macvlan_common_newlink(src_net, dev, tb, data,

				      macvtap_receive, macvtap_forward);

	if (err)

		goto out;



	devt = MKDEV(MAJOR(macvtap_major), dev->ifindex);



	classdev = device_create(macvtap_class, &dev->dev, devt,

				 dev, "tap%d", dev->ifindex);

	if (IS_ERR(classdev)) {

		err = PTR_ERR(classdev);

		macvtap_del_queues(dev);

	}



out:

	return err;

}



static void macvtap_dellink(struct net_device *dev,

			    struct list_head *head)

{

	device_destroy(macvtap_class,

		       MKDEV(MAJOR(macvtap_major), dev->ifindex));



	macvtap_del_queues(dev);

	macvlan_dellink(dev, head);

}
@@ -975,6 +957,42 @@ struct socket *macvtap_get_socket(struct file *file) 
}

EXPORT_SYMBOL_GPL(macvtap_get_socket);



static int macvtap_device_event(struct notifier_block *unused,

				unsigned long event, void *ptr)

{

	struct net_device *dev = ptr;

	struct device *classdev;

	dev_t devt;



	if (dev->rtnl_link_ops != &macvtap_link_ops)

		return NOTIFY_DONE;





	switch (event) {

	case NETDEV_REGISTER:

		/* Create the device node here after the network device has

		 * been registered but before register_netdevice has

		 * finished running.

		 */

		devt = MKDEV(MAJOR(macvtap_major), dev->ifindex);

		classdev = device_create(macvtap_class, &dev->dev, devt,

					 dev, "tap%d", dev->ifindex);

		if (IS_ERR(classdev))

			return notifier_from_errno(PTR_ERR(classdev));

		break;

	case NETDEV_UNREGISTER:

		devt = MKDEV(MAJOR(macvtap_major), dev->ifindex);

		device_destroy(macvtap_class, devt);

		break;

	}



	return NOTIFY_DONE;

}



static struct notifier_block macvtap_notifier_block __read_mostly = {

	.notifier_call	= macvtap_device_event,

};



static int macvtap_init(void)

{

	int err;
@@ -995,12 +1013,18 @@ static int macvtap_init(void) 
		goto out3;

	}



	err = macvlan_link_register(&macvtap_link_ops);

	err = register_netdevice_notifier(&macvtap_notifier_block);

	if (err)

		goto out4;



	err = macvlan_link_register(&macvtap_link_ops);

	if (err)

		goto out5;



	return 0;



out5:

	unregister_netdevice_notifier(&macvtap_notifier_block);

out4:

	class_unregister(macvtap_class);

out3:
@@ -1015,6 +1039,7 @@ module_init(macvtap_init); 
static void macvtap_exit(void)

{

	rtnl_link_unregister(&macvtap_link_ops);

	unregister_netdevice_notifier(&macvtap_notifier_block);

	class_unregister(macvtap_class);

	cdev_del(&macvtap_cdev);

	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);