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

[David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>]

From: Huang Qiang <h.huangqiang-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Date: Thu, 12 Jul 2012 17:33:34 +0800

> From: Yang Zhenzhang <yangzhenzhang-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
> 
> 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@host socket]# lxc-start -n test -f config /bin/bash
> [root@net-test socket]# ip route add default via 192.168.58.2
> [root@net-test socket]# echo 0 0 0 > /proc/sys/net/ipv4/tcp_mem
> [root@net-test socket]# scp root-Q0ErXNX1RuabR28l3DCWlg@public.gmane.org:/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-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
> Signed-off-by: Huang Qiang <h.huangqiang-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>

This patch doesn't apply cleanly to net-next, please respin it.

Thank you.