Re: [PATCH RESEND 0/4] device_cgroup: replace internally whitelistwith exception list

From: Andrew Morton
Date: Thu Aug 16 2012 - 16:08:39 EST


On Thu, 09 Aug 2012 15:04:14 -0400
aris@xxxxxxxxx wrote:

> The original model of device_cgroup is having a whitelist where all the
> allowed devices are listed. The problem with this approach is that is
> impossible to have the case of allowing everything but few devices.
>
> The reason for that lies in the way the whitelist is handled internally:
> since there's only a whitelist, the "all devices" entry would have to be
> removed and replaced by the entire list of possible devices but the ones
> that are being denied. Since dev_t is 32 bits long, representing the allowed
> devices as a bitfield is not memory efficient.
>
> This patch replaces the "whitelist" by a "exceptions" list and the default
> policy is kept as "deny_all" variable in dev_cgroup structure.

The patches look reasonable to me. I suggest you resend them after
kernel summit and cc a few additional people: Serge Hallyn, Pavel
Emelyanov and James Morris.
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