Re: [PATCH]: Schedule correct qdisc in watchdog.

[Jarek Poplawski <jarkao2@gmail.com>]

On Tue, Aug 19, 2008 at 05:37:45AM +0000, Jarek Poplawski wrote:
> On Mon, Aug 18, 2008 at 04:56:38PM -0700, David Miller wrote:
> > From: Jarek Poplawski <jarkao2@gmail.com>
> > Date: Mon, 18 Aug 2008 12:58:05 +0000
> > 
> > > On Mon, Aug 18, 2008 at 03:45:29PM +0300, Denys Fedoryshchenko wrote:
> > > > Patch applied, got another warning.
> > > 
> > > I hope I'll figure this out before evening. Probably it's safer
> > > to stop testing for a while.
> > 
> > We have to put the kfree() of the qdisc back into an RCU handler,
> > that's all.
> 
> As a matter of fact, I still have some doubts about this. Top level
> qdiscs must be deactivated before destroy and during this process we
> make sure nothing can use them anymore. So, since this all is under
> rtnl_lock(), I wonder if we really need this qdisc root_lock around
> qdisc_destroy() for root qdiscs at all.
> 
> Maybe there are some common lists which depend on this and rtnl_lock
> isn't enough for them. If so, maybe it's easier to change locking in
> these places. But, of course, I can miss something.
> 
> I'm not against RCU here if it's really needed. Otherwise, this
> destroying in softirq context, without rtnl_lock() looks like a
> potential obstacle for the future.

Hmm.. I see it is considered in another messages - I've to do some
reading then.

Jarek P.