[patch net-next] net: add netnotifier event for upper device change

[patch net-next] net: add netnotifier event for upper device change

[Jiri Pirko]

Now when upper device is changed, event is not propagated via RT Netlink
to userspace. Userspace might never now about the change. Fix this by
adding upper-device-change notifier event.

Signed-off-by: Jiri Pirko <jiri@resnulli.us>
---
 include/linux/netdevice.h | 1 +
 net/core/dev.c            | 3 ++-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0ebd63a..ea7b6bc 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1593,6 +1593,7 @@ struct packet_offload {
 #define NETDEV_RELEASE		0x0012
 #define NETDEV_NOTIFY_PEERS	0x0013
 #define NETDEV_JOIN		0x0014
+#define NETDEV_CHANGEUPPER	0x0015
 
 extern int register_netdevice_notifier(struct notifier_block *nb);
 extern int unregister_netdevice_notifier(struct notifier_block *nb);
diff --git a/net/core/dev.c b/net/core/dev.c
index 7229bc3..50c02de 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4411,7 +4411,7 @@ static int __netdev_upper_dev_link(struct net_device *dev,
 	else
 		list_add_tail_rcu(&upper->list, &dev->upper_dev_list);
 	dev_hold(upper_dev);
-
+	call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
 	return 0;
 }
 
@@ -4471,6 +4471,7 @@ void netdev_upper_dev_unlink(struct net_device *dev,
 	list_del_rcu(&upper->list);
 	dev_put(upper_dev);
 	kfree_rcu(upper, rcu);
+	call_netdevice_notifiers(NETDEV_CHANGEUPPER, dev);
 }
 EXPORT_SYMBOL(netdev_upper_dev_unlink);
 
-- 
1.8.1.4

Re: [patch net-next] net: add netnotifier event for upper device change

[David Miller]

From: Jiri Pirko <jiri@resnulli.us>
Date: Sat, 25 May 2013 16:12:10 +0200

> Now when upper device is changed, event is not propagated via RT Netlink
> to userspace. Userspace might never now about the change. Fix this by
> adding upper-device-change notifier event.
> 
> Signed-off-by: Jiri Pirko <jiri@resnulli.us>

Looks good, applied, thanks Jiri.

If someone is looking for a useful project, switching networking over to
a more typed notifier system would be a worthwhile improvement.

It's hard to right now to communicate what changed beyond "action X
happened to this object, you have to check to see exactly how it
changed"

This came up recently with the IFF_NOARP stuff.

Re: [patch net-next] net: add netnotifier event for upper device change

[Jiri Pirko]

Sun, May 26, 2013 at 08:14:13AM CEST, davem@davemloft.net wrote:
>From: Jiri Pirko <jiri@resnulli.us>
>Date: Sat, 25 May 2013 16:12:10 +0200
>
>> Now when upper device is changed, event is not propagated via RT Netlink
>> to userspace. Userspace might never now about the change. Fix this by
>> adding upper-device-change notifier event.
>> 
>> Signed-off-by: Jiri Pirko <jiri@resnulli.us>
>
>Looks good, applied, thanks Jiri.
>
>If someone is looking for a useful project, switching networking over to
>a more typed notifier system would be a worthwhile improvement.
>
>It's hard to right now to communicate what changed beyond "action X
>happened to this object, you have to check to see exactly how it
>changed"

Hmm. Do you have something particular in mind? My first thought was
passing some union instead of NETDEV_* numbers.

>
>This came up recently with the IFF_NOARP stuff.

Can you point me to the discussion?

Thanks

Jiri

Re: [patch net-next] net: add netnotifier event for upper device change

[David Miller]

From: Jiri Pirko <jiri@resnulli.us>
Date: Sun, 26 May 2013 09:10:39 +0200

> Sun, May 26, 2013 at 08:14:13AM CEST, davem@davemloft.net wrote:
>>If someone is looking for a useful project, switching networking over to
>>a more typed notifier system would be a worthwhile improvement.
>>
>>It's hard to right now to communicate what changed beyond "action X
>>happened to this object, you have to check to see exactly how it
>>changed"
> 
> Hmm. Do you have something particular in mind? My first thought was
> passing some union instead of NETDEV_* numbers.

Part of the problem is that notifiers are untyped.

So you can say "NETDEV_* means struct foo" but nothing in the C
typing system will enforce this, so errors are inevitable.

Perhaps one level of encapsulation will help:

static inline call_netdevice_feat_change(struct net_device *dev,
					 netdev_features_t old,
					 netdev_features_t new)
{
	struct netdevice_feat_change_info info;

	info.dev = dev;
	info.old = old;
	info.new = new;
	call_netdevice_notifiers(NETDEV_FEAT_CHANGE, &info);
}

>>This came up recently with the IFF_NOARP stuff.
> 
> Can you point me to the discussion?

It's in this patchwork thread:

http://patchwork.ozlabs.org/patch/245256/