[net-2.6 patch 0/2][NETNS] netns fixes

[net-2.6 patch 0/2][NETNS] netns fixes

[Daniel Lezcano]

The two following patches fix bugs related to the network
namespace. The first one fixes a sysfs issue (when using the
sysfs per namespace), and the second one fixes the frag timer
for ipv6 to use the right network namespace.

-- 

[net-2.6 patch 1/2][NETNS] fix device renaming for sysfs

[Daniel Lezcano]

[-- Attachment #1: fix-kobject.patch --]
[-- Type: text/plain, Size: 3206 bytes --]

When a netdev is moved across namespaces with the 'dev_change_net_namespace' 
function, the 'device_rename' function is used to fixup kobject and refresh 
the sysfs tree. The device_rename function will call kobject_rename and this
one will check if there is an object with the same name and this is the case
because we are renaming the object with the same name.

The use of 'device_rename' seems for me wrong because we usually don't
rename it but just move it across namespaces. As we just want to do a 
mini "netdev_[un]register", IMO the functions 'netdev_[un]register_kobject' 
should be used instead, like an usual network device [un]registering.

This patch replace device_rename by netdev_unregister_kobject, followed by
netdev_register_kobject.

The netdev_register_kobject will call device_initialize and will raise a 
warning indicating the device was already initialized. In order to fix that,
I split the device initialization into a separate function and use it together
with 'netdev_register_kobject' into register_netdevice. So we can safely call
'netdev_register_kobject' in 'dev_change_net_namespace'.

This fix will allow to properly use the sysfs per namespace which is coming
from -mm tree.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: Benjamin Thery <benjamin.thery@bull.net>
---
 net/core/dev.c       |    4 +++-
 net/core/net-sysfs.c |    7 ++++++-
 net/core/net-sysfs.h |    2 +-
 3 files changed, 10 insertions(+), 3 deletions(-)

Index: net-2.6/net/core/dev.c
===================================================================
--- net-2.6.orig/net/core/dev.c
+++ net-2.6/net/core/dev.c
@@ -3776,6 +3776,7 @@ int register_netdevice(struct net_device
 		}
 	}
 
+	netdev_initialize_kobject(dev);
 	ret = netdev_register_kobject(dev);
 	if (ret)
 		goto err_uninit;
@@ -4208,7 +4209,8 @@ int dev_change_net_namespace(struct net_
 	}
 
 	/* Fixup kobjects */
-	err = device_rename(&dev->dev, dev->name);
+	netdev_unregister_kobject(dev);
+	err = netdev_register_kobject(dev);
 	WARN_ON(err);
 
 	/* Add the device back in the hashes */
Index: net-2.6/net/core/net-sysfs.c
===================================================================
--- net-2.6.orig/net/core/net-sysfs.c
+++ net-2.6/net/core/net-sysfs.c
@@ -449,7 +449,6 @@ int netdev_register_kobject(struct net_d
 	struct device *dev = &(net->dev);
 	struct attribute_group **groups = net->sysfs_groups;
 
-	device_initialize(dev);
 	dev->class = &net_class;
 	dev->platform_data = net;
 	dev->groups = groups;
@@ -470,6 +469,12 @@ int netdev_register_kobject(struct net_d
 	return device_add(dev);
 }
 
+void netdev_initialize_kobject(struct net_device *net)
+{
+	struct device *device = &(net->dev);
+	device_initialize(device);
+}
+
 int netdev_kobject_init(void)
 {
 	return class_register(&net_class);
Index: net-2.6/net/core/net-sysfs.h
===================================================================
--- net-2.6.orig/net/core/net-sysfs.h
+++ net-2.6/net/core/net-sysfs.h
@@ -4,5 +4,5 @@
 int netdev_kobject_init(void);
 int netdev_register_kobject(struct net_device *);
 void netdev_unregister_kobject(struct net_device *);
-
+void netdev_initialize_kobject(struct net_device *);
 #endif

-- 

Re: [net-2.6 patch 1/2][NETNS] fix device renaming for sysfs

[David Miller]

From: Daniel Lezcano <dlezcano@fr.ibm.com>
Date: Wed, 30 Apr 2008 23:31:14 +0200

> When a netdev is moved across namespaces with the 'dev_change_net_namespace' 
> function, the 'device_rename' function is used to fixup kobject and refresh 
> the sysfs tree. The device_rename function will call kobject_rename and this
> one will check if there is an object with the same name and this is the case
> because we are renaming the object with the same name.
> 
> The use of 'device_rename' seems for me wrong because we usually don't
> rename it but just move it across namespaces. As we just want to do a 
> mini "netdev_[un]register", IMO the functions 'netdev_[un]register_kobject' 
> should be used instead, like an usual network device [un]registering.
> 
> This patch replace device_rename by netdev_unregister_kobject, followed by
> netdev_register_kobject.
> 
> The netdev_register_kobject will call device_initialize and will raise a 
> warning indicating the device was already initialized. In order to fix that,
> I split the device initialization into a separate function and use it together
> with 'netdev_register_kobject' into register_netdevice. So we can safely call
> 'netdev_register_kobject' in 'dev_change_net_namespace'.
> 
> This fix will allow to properly use the sysfs per namespace which is coming
> from -mm tree.
> 
> Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
> Acked-by: Benjamin Thery <benjamin.thery@bull.net>

Looks good, applied.

Re: [net-2.6 patch 1/2][NETNS] fix device renaming for sysfs

[Eric W. Biederman]

Daniel Lezcano <dlezcano@fr.ibm.com> writes:

> When a netdev is moved across namespaces with the 'dev_change_net_namespace' 
> function, the 'device_rename' function is used to fixup kobject and refresh 
> the sysfs tree. The device_rename function will call kobject_rename and this
> one will check if there is an object with the same name and this is the case
> because we are renaming the object with the same name.
>
> The use of 'device_rename' seems for me wrong because we usually don't
> rename it but just move it across namespaces. As we just want to do a 
> mini "netdev_[un]register", IMO the functions 'netdev_[un]register_kobject' 
> should be used instead, like an usual network device [un]registering.

device_rename is correct.  Because doing device_del; device_add removes
any driver specific sysfs attributes.

Causing your patch to introduce subtle driver breakage only when we
move a network device between namespaces.  Ouch!

To support this operation we need something like device_rename that
can preserve driver specific attributes, and generally handle
movement between namespaces.  Since device_rename already does 99% of
what we need it to do I found it easier to extend device_rename to
handle this case then to introduce yet another function into the
kobject layer.

> This patch replace device_rename by netdev_unregister_kobject, followed by
> netdev_register_kobject.

And sysfs comes a' tumblin' down.

My apologies for not replying sooner I just spotted this.

Eric

Re: [net-2.6 patch 1/2][NETNS] fix device renaming for sysfs

[Daniel Lezcano]

Eric W. Biederman wrote:
> Daniel Lezcano <dlezcano@fr.ibm.com> writes:
> 
>> When a netdev is moved across namespaces with the 'dev_change_net_namespace' 
>> function, the 'device_rename' function is used to fixup kobject and refresh 
>> the sysfs tree. The device_rename function will call kobject_rename and this
>> one will check if there is an object with the same name and this is the case
>> because we are renaming the object with the same name.
>>
>> The use of 'device_rename' seems for me wrong because we usually don't
>> rename it but just move it across namespaces. As we just want to do a 
>> mini "netdev_[un]register", IMO the functions 'netdev_[un]register_kobject' 
>> should be used instead, like an usual network device [un]registering.
> 
> device_rename is correct.  Because doing device_del; device_add removes
> any driver specific sysfs attributes.
> 
> Causing your patch to introduce subtle driver breakage only when we
> move a network device between namespaces.  Ouch!
> 
> To support this operation we need something like device_rename that
> can preserve driver specific attributes, and generally handle
> movement between namespaces.  Since device_rename already does 99% of
> what we need it to do I found it easier to extend device_rename to
> handle this case then to introduce yet another function into the
> kobject layer.
> 
>> This patch replace device_rename by netdev_unregister_kobject, followed by
>> netdev_register_kobject.
> 
> And sysfs comes a' tumblin' down.
> My apologies for not replying sooner I just spotted this.

My fault, I should have Cc'ed you when sending the email :(
Thanks for looking at this patch.

   -- Daniel

[net-2.6 patch 2/2][NETNS] Fix reassembly timer to use the right namespace

[Daniel Lezcano]

[-- Attachment #1: fix-reassembly-timer.patch --]
[-- Type: text/plain, Size: 920 bytes --]

This trivial fix retrieves the network namespace from frag queue
and use it to get the network device in the right namespace.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
---
 net/ipv6/reassembly.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Index: net-2.6/net/ipv6/reassembly.c
===================================================================
--- net-2.6.orig/net/ipv6/reassembly.c
+++ net-2.6/net/ipv6/reassembly.c
@@ -197,6 +197,7 @@ static void ip6_frag_expire(unsigned lon
 {
 	struct frag_queue *fq;
 	struct net_device *dev = NULL;
+	struct net *net;
 
 	fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q);
 
@@ -207,7 +208,8 @@ static void ip6_frag_expire(unsigned lon
 
 	fq_kill(fq);
 
-	dev = dev_get_by_index(&init_net, fq->iif);
+	net = container_of(fq->q.net, struct net, ipv6.frags);
+	dev = dev_get_by_index(net, fq->iif);
 	if (!dev)
 		goto out;
 

-- 

Re: [net-2.6 patch 2/2][NETNS] Fix reassembly timer to use the right namespace

[David Miller]

From: Daniel Lezcano <dlezcano@fr.ibm.com>
Date: Wed, 30 Apr 2008 23:31:15 +0200

> This trivial fix retrieves the network namespace from frag queue
> and use it to get the network device in the right namespace.
> 
> Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>

The one area where ipv4 and ipv6 code didn't get fully
considated, and voila!  ipv4 got it right and ipv6 had
the bug :-)

Patch applied, thanks!