On Thu, Sep 10, 2020 at 07:07:57PM +0200, Gerald Schaefer wrote:

I might have lost track a bit. Are we still talking about possible
functional impacts of either our current pagetable walking with s390
(apart from gup_fast), or the proposed generic change (for s390, or
others?)?

I'm looking for an more understandable explanation what is wrong with
the S390 implementation.

If the page operations require the invariant I described then it is
quite easy to explain the problem and understand the solution.

Jason