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To: Patrick McHardy <kaber@trash.net>
Cc: Rainer Weikusat <rweikusat@mobileactivedefense.com>,
        netfilter-devel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] netfilter: add per-namespace logging to nfnetlink_log.c
In-Reply-To: <8739i3fp6s.fsf@sapphire.mobileactivedefense.com> (Rainer Weikusat's message of "Mon\, 18 Jul 2011 18\:56\:11 +0100")
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From: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Date: Mon, 18 Jul 2011 20:11:33 +0100
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Rainer Weikusat <rw@sapphire.mobileactivedefense.com> writes:
> Patrick McHardy <kaber@trash.net> writes:

[...]

>>> +#define INSTANCE_BUCKETS	16
>>> +
>>> +struct nfulnl_instances {
>>> +	spinlock_t lock;
>>> +	atomic_t global_seq;
>>> +	struct hlist_head table[INSTANCE_BUCKETS];
>>> +	unsigned hash_init;
>>> +#ifdef NET_NS
>>> +	struct net *net;
>>> +#endif
>>> +};
>>> +
>>>  struct nfulnl_instance {
>>>  	struct hlist_node hlist;	/* global list of instances */
>>>  	spinlock_t lock;
>>> @@ -67,14 +85,92 @@ struct nfulnl_instance {
>>>  	u_int16_t flags;
>>>  	u_int8_t copy_mode;
>>>  	struct rcu_head rcu;
>>> +#ifdef NET_NS
>>> +	struct nfulnl_instances *instances;
>>> +#endif
>>
>> This seems odd, the usual way is to add the global data to the
>> net-ns structure.
>
> Since a facility for having 'per subsystem' network namespace specific
> data exists, there seems to be little reason to not use it.

An additional remark: There is actually a reason for using it, namely,
'adding global data to the net-ns structure' implies that this
structure has to contain per-module data of modules which aren't
loaded, while using 'generic net pointers' enables this data to be
allocated/ deallocated on module load/ unload.