Lucid SRU - UBUNTU: SAUCE: netns: Add quota for number of NET_NS instances.

[Serge Hallyn]

Quoting Tim Gardner (tim.gardner at canonical.com):
> On 12/19/2011 08:32 AM, Serge Hallyn wrote:
> >Quoting Brad Figg (brad.figg at canonical.com):
> >>On 12/01/2011 01:48 PM, Tim Gardner wrote:
> >>>Please consider this (untested) patch for inclusion in Lucid. See the discussion in http://bugs.launchpad.net/bugs/790863 for arguments proposing to restore CONFIG_NET_NS.
> >>>
> >>>I'll post a test kernel to the bug in awhile.
> >>>
> >>>One of the issues I have with this patch is that it appears that any consumer of network name spaces will have to initially write a non-zero value to netns_max before _any_ name spaces can be successfully allocated. If copy_net_ns() fails in
> >>>create_new_namespaces(), then it seems the whole allocation is buggered.
> >>>
> >>>rtg
> >>>
> >>>
> >>
> >>Tim,
> >>
> >>If you follow the thread that starts at:
> >>http://www.spinics.net/lists/netdev/msg180263.html
> >>you will see that Tetsuo actually proposed a modified
> >>version of this patch: http://www.spinics.net/lists/netdev/msg180360.html.
> >
> >(Shouldn't used_netns_count default to 1?  :)
> >
> >It looks good, I'd only ask that a warning be printed, even if only
> >printk_once(), when the limit is hit.  Otherwise we risk mysterious
> >bugs reported against other software.
> >
> >Acked-by: Serge Hallyn<serge.hallyn at canonical.com>
> >
> >thanks,
> >-serge
> 
> Serge - How about this? Changes include a non-zero initial value for
> max_netns_count, and a printk_once() warning if the count is ever
> exceeded.

Looks great, thanks.

Acked-by: Serge Hallyn <serge.hallyn at canonical.com>

-serge