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From: Gao feng <gaofeng@cn•fujitsu.com>
To: Pablo Neira Ayuso <pablo@netfilter•org>
Cc: davem@davemloft•net, eric.dumazet@gmail•com,
	steffen.klassert@secunet•com, netfilter-devel@vger•kernel.org,
	linux-rdma@vger•kernel.org, netdev@vger•kernel.org,
	linux-crypto@vger•kernel.org, stephen.hemminger@vyatta•com,
	jengelh@inai•de
Subject: Re: [patch v2 04/11] nf_conntrack_netlink: pass nf_conntrack_netlink module to netlink_dump_start
Date: Wed, 26 Sep 2012 20:35:53 +0800	[thread overview]
Message-ID: <5062F6A9.7020309@cn.fujitsu.com> (raw)
In-Reply-To: <20120926095837.GA23815@1984>

于 2012年09月26日 17:58, Pablo Neira Ayuso 写道:
> On Wed, Sep 26, 2012 at 05:42:31PM +0800, Gao feng wrote:
>> Hi Pablo:
>>
>> 于 2012年09月26日 17:26, Pablo Neira Ayuso 写道:
>>> On Wed, Sep 26, 2012 at 04:41:21PM +0800, Gao feng wrote:
>>>> use proper netlink_dump_control.done and .module to avoid panic.
>>>>
>>>> Signed-off-by: Gao feng <gaofeng@cn•fujitsu.com>
>>>> ---
>>>>  net/netfilter/nf_conntrack_netlink.c |    8 ++++++++
>>>>  1 files changed, 8 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
>>>> index 9807f32..509a257 100644
>>>> --- a/net/netfilter/nf_conntrack_netlink.c
>>>> +++ b/net/netfilter/nf_conntrack_netlink.c
>>>> @@ -706,6 +706,7 @@ static int ctnetlink_done(struct netlink_callback *cb)
>>>>  		nf_ct_put((struct nf_conn *)cb->args[1]);
>>>>  	if (cb->data)
>>>>  		kfree(cb->data);
>>>> +	netlink_dump_done(cb);
>>>
>>> I think you can call netlink_dump_done from af_netlink.c:
>>>
>>> static int netlink_dump(struct sock *sk) 
>>>         ...
>>>         if (cb->done) {
>>>                 cb->done(cb);
>>>                 netlink_dump_done(...);
>>>         }
>>>
>>> Thus, you don't need to change netlink_dump_control in every netlink
>>> subsystem.
>>
>> because cb->done is called by netlink_sock_destruct too,it's very usefully
>> when userspace program only send dump request to kernel without reading
>> data from kernel.
> 
> Then add that to netlink_sock_destruct as well. If possible, I prefer
> if this remains in the netlink core to avoid leaking module refcount
> if you forget to call netlink_dump_done.

make sense,I will update it in next version.
Thanks!

> 
>>>
>>>>  	return 0;
>>>>  }
>>>>  
>>>> @@ -1022,6 +1023,7 @@ ctnetlink_get_conntrack(struct sock *ctnl, struct sk_buff *skb,
>>>>  		struct netlink_dump_control c = {
>>>>  			.dump = ctnetlink_dump_table,
>>>>  			.done = ctnetlink_done,
>>>> +			.module = THIS_MODULE,
>>>
>>> You can do something similar to:
>>>
>>> 9f00d97 netlink: hide struct module parameter in netlink_kernel_create
>>>
>>> by definiting netlink_dump_start as static inline and using
>>> THIS_MODULE from there.
>>>
>>> If I'm not missing anything, with those two changes, you will not need
>>> to modify any caller and it will result one single patch.
>>>
>>
>> You can see the patch [11/11], THIS_MODULE in infiniband/core/cma.c
>> means module rdma_cm,but we call netlink_dump_start in infiniband/core/netlink.c
> 
> You can still use __netlink_dump_start for that case, which allows you
> to specify a custom struct module * parameter. But for most cases,
> netlink_dump_start (which hides THIS_MODULE) should be fine.
> 

I don't know how to deal with module_put in this way.
and I think my  way is simple enough.

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  reply	other threads:[~2012-09-26 12:35 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-26  8:41 [patch v2 01/11] netlink: add reference of module in netlink_dump_start Gao feng
2012-09-26  8:41 ` [patch v2 02/11] inet_diag: pass inet_diag module to netlink_dump_start Gao feng
2012-09-26  8:41 ` [patch v2 03/11] unix_diag: pass unix_diag " Gao feng
2012-09-26  8:41 ` [patch v2 04/11] nf_conntrack_netlink: pass nf_conntrack_netlink " Gao feng
2012-09-26  9:25   ` Gao feng
2012-09-26  9:26   ` Pablo Neira Ayuso
2012-09-26  9:42     ` Gao feng
2012-09-26  9:58       ` Pablo Neira Ayuso
2012-09-26 12:35         ` Gao feng [this message]
     [not found]           ` <5062F6A9.7020309-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-09-26 15:04             ` Pablo Neira Ayuso
2012-09-27  0:14               ` Gao feng
2012-09-26  8:41 ` [patch v2 05/11] nfnetlink_acct: pass nfnetlink_acct " Gao feng
     [not found] ` <1348648888-24943-1-git-send-email-gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
2012-09-26  8:41   ` [patch v2 06/11] nfnetlink_cthelper: pass nfnetlink_cthelper " Gao feng
2012-09-26  8:41   ` [patch v2 07/11] nfnetlink_cttimeout: pass nfnetlink_cttimeout " Gao feng
2012-09-26  8:41   ` [patch v2 10/11] ipset: pass ipset " Gao feng
2012-09-26  8:41   ` [patch v2 11/11] infiniband: pass rdma_cm " Gao feng
2012-09-26  8:41 ` [patch v2 08/11] crypto: pass crypto_user " Gao feng
2012-09-26  8:41 ` [patch v2 09/11] xfrm: pass xfrm_user " Gao feng

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