[CRIU] RFC: Add owner user namespace to tty_struct

[Cyrill Gorcunov]

On Mon, May 29, 2017 at 12:43:52PM +0300, Pavel Emelyanov wrote:
> > 
> > Hi Matt! Currently we don't use fake input in criu so at moment it won't
> > affect us anyhow, but in longterm I expect more owner_user_ns testing may
> > appear. Thus we will need to know which owner tty belong to. I think we
> > may extend tty_fops and use show_fdinfo method to print owner_user_ns.
> 
> We have similar problem with net_device:net pairing and with userns:<any other ns>
> one -- we need to know which object belongs to which. For the net_device:net case
> there has appeared a netdev ioctl, that results in an opened namespace file, just
> like if we did open("/proc/pid/ns/net"). I think the same API would be more convenient
> for tty:userns. All the more so there's already plenty of ioctls for ttys :)

Mind to point which netdev ioctl it is?