[PATCH v2] netns: correctly use per-netns ipv4 sysctl_tcp_mem

[Huang Qiang]

On 2012-7-19 0:41, David Miller wrote:

> From: Huang Qiang <h.huangqiang at huawei.com>
> Date: Thu, 12 Jul 2012 17:33:34 +0800
> 
>> From: Yang Zhenzhang <yangzhenzhang at huawei.com>
>>
>> Now, kernel allows each net namespace to independently set up its levels
>> for tcp memory pressure thresholds.
>>
>> But it seems there is a bug, as using the following steps:
>>
>> [root at host socket]# lxc-start -n test -f config /bin/bash
>> [root at net-test socket]# ip route add default via 192.168.58.2
>> [root at net-test socket]# echo 0 0 0 > /proc/sys/net/ipv4/tcp_mem
>> [root at net-test socket]# scp root at 192.168.58.174:/home/tcp_mem_test .
>>
>> and it still can transport the "tcp_mem_test" file which we hope it
>> would not.
>>
>> It's because inet_init() (net/ipv4/af_inet.c)initialize the tcp_prot.sysctl_mem:
>> tcp_prot.sysctl_mem = init_net.ipv4.sysctl_tcp_mem;
>>
>> So when the protocal is TCP, sk->sk_prot->sysctl_mem(following code)
>> always use the ipv4 sysctl_tcp_mem of init_net namespace rather than
>> it's own net namespace.
>> This patch simply set "prot" equal to net->ipv4.sysctl_tcp_mem when
>> the protocol type is TCP.
>>
>> Signed-off-by: Yang Zhenzhang <yangzhenzhang at huawei.com>
>> Signed-off-by: Huang Qiang <h.huangqiang at huawei.com>
> 
> This patch doesn't apply cleanly to net-next, please respin it.
> 
> Thank you.

Ok, I will send patch v3 for net-next. Thank you!