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

[Serge Hallyn]

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