Re: [PATCH 20/31]: pkt_sched: Perform bulk of qdisc destruction in RCU.

[Patrick McHardy <kaber@trash.net>]

David Miller wrote:
> From: Patrick McHardy <kaber@trash.net>
> Date: Thu, 17 Jul 2008 15:03:35 +0200
> 
>> Still working my way through the patches, but this one caught my
>> eye (we had this before and it caused quite a few problems).
> 
> Indeed, it's the most delicate change.
> 
> Thanks for the info about all the tricky bits in this area.

One thought that occured to me - we could avoid all the visiblity
issues wrt. dev->qdisc_list by simply getting rid of it :)

If we move the qdisc list from the device to the root Qdisc itself,
it would become invisible automatically as soon as we assign a new
root qdisc to the netdev_queue. Iteration would become slightly
more complicated since we'd have to iterate over all netdev_queues,
but I think it should avoid most of the problems I mentioned
(besides the u32_list thing).