On Wed, Jun 3, 2020 at 8:19 PM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> I have tried to fix it up, partly by editing the patches directly, and
> partly by then trying to fix up comments after-the-fact.
The end result passes the smell test, boots for me, and looks like it
might work.
But I don't have any good real-world test for this, and I hope and
assume that John has something GPU-related that actually uses the code
and cares. Presumably there was _something_ that triggered those
changes to de-duplicate that code?
So please give it a look. Because of how I edited the patches (and
Andrew edited them before me), what is attributed to John Hubbard
isn't really the same as the patch he originally wrote.
If I broke something in the process, feel free to let me know in less
than polite terms. But it look better than the intermediate situation
that definitely looked like it would just fail entirely on any
read-only mappings due to not being able to fall back on the slow
case.
The drm code probably doesn't even care about the possible ambiguity
with GUP picking a COW page that might later break the other way.
Linus
