Re: [RFC][PATCH] kmap_atomic_push

David Howells
2009-10-08T23:00:13Z

Peter Zijlstra <peterz@infradead.org> wrote:

> I can think of code that does a lot more than that, suppose you have
> both KM_USER[01], get an interrupt that takes KM_IRQ[01], take an NMI
> that takes KM_NMI.

But whilst the interrupt might want to use two slots, it's probably a bug for
it to want to access the mappings set up by whatever called KM_USER[01] - so
it can probably reuse those slots, provided it puts them back again.

Similarly for NMI taking KM_NMI - it probably shouldn't be attempting to
access the mappings set up by the normal mode or the interrupt mode - in which
case, why can't it reuse those slots?

> Maybe we can stack the SOFTIRQ ones in as well ;-)

Ditto.

David