mmotm threatens ppc preemption again

[Benjamin Herrenschmidt]

On Thu, 2011-03-31 at 10:21 -0700, Jeremy Fitzhardinge wrote:
> 
> No, its the same accessors for both, since the need to distinguish them
> hasn't really come up.  Could you put a "if (preemptable()) return;"
> guard in your implementations?

That would be a band-aid but would probably do the trick for now
for !-rt, tho it wouldn't do the right thing for -rt... 

> Otherwise I have no objections to passing the mm in (we'll probably just
> continue to ignore the arg in x86-land).

Ben.