Message-ID: <5005E390.7020706@intel.com> (sfid-20120718_001343_183513_A59B85EF)
Date: Tue, 17 Jul 2012 15:13:36 -0700
From: John Fastabend <john.r.fastabend@intel.com>
MIME-Version: 1.0
To: David Miller <davem@davemloft.net>
CC: mark.d.rustad@intel.com, netdev@vger.kernel.org,
	linux-wireless@vger.kernel.org, netfilter-devel@vger.kernel.org
Subject: Re: That's pretty much it for 3.5.0
References: <5005B881.8010505@intel.com> <20120717.122459.2240133900020140698.davem@davemloft.net> <5005D008.6060103@intel.com> <20120717.140241.1599386555723262095.davem@davemloft.net>
In-Reply-To: <20120717.140241.1599386555723262095.davem@davemloft.net>
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Sender: linux-wireless-owner@vger.kernel.org

On 7/17/2012 2:02 PM, David Miller wrote:
> From: John Fastabend <john.r.fastabend@intel.com>
> Date: Tue, 17 Jul 2012 13:50:16 -0700
>
>> On 7/17/2012 12:24 PM, David Miller wrote:
>>> From: John Fastabend <john.r.fastabend@intel.com>
>>> Date: Tue, 17 Jul 2012 12:09:53 -0700
>>>
>>>> although we don't have an early_init hook for netprio_cgroup so this
>>>> is probably not correct.
>>>
>>> The dependency is actually on net_dev_init (a subsys_initcall) rather
>>> than a pure_initcall.
>>>
>>> net_dev_init is what registers the netdev_net_ops, which in turn
>>> initializes the netdev list in namespaces such as &init_net
>>>
>>
>> Ah right thanks sorry for the thrash. I guess we need to check if the
>> netdev list in the init_net namespace is initialized.
>
> It's a hack, but we could export and then test dev_boot_phase == 0,
> and if that test is true then skip the init_net device walk in the
> cgroup code.
>
> But I don't like that very much.
>
> The things this code cares about can't even be an issue until
> net_dev_init() runs.
>
> There is a comment warning not to do this in linux/init.h, but we
> could change the module_init() in netprio_cgroup.c to some level which
> runs after subsys_inticall().  When built as a module, linux/init.h
> will translate this into module_init() which is basically the behavior
> we want.
>

Perhaps the easiest way is to check net->count this should be zero
until setup_net is called.

if (!atomic_read(&init_net.count))
	return ret;