Re: [PATCH 2.6 1/5]: Fix locking in __qdisc_destroy rcu-callback

[Patrick McHardy <kaber@xxxxxxxxx>]

David S. Miller wrote:

> On Tue, 03 Aug 2004 17:20:36 +0200
> Patrick McHardy <kaber@xxxxxxxxx> wrote:
>  
>
> > I'm not sure if RCU callback can be scheduled while the kernel is
> >
> > running in process context, so this may be unneccessary.
> >    
>
> RCU callbacks run via tasklets, and thus in softirq context,
> thus your locking changes to _bh() are indeed necessary.
>  
I meant because in my understanding of RCU the quintescent state is
not reached while the CPU is running kernel code, so the callback can't
be scheduled. A previously scheduled callback should finish before
further kernel code is run in process context.

Regards
Patrick