Re: [PATCH 04/10] drm/i915: Fix MAX_ORDER usage in i915_gem_object_get_pages_internal()

From: Kirill A. Shutemov
Date: Wed Mar 15 2023 - 11:39:05 EST


On Wed, Mar 15, 2023 at 03:35:23PM +0000, Tvrtko Ursulin wrote:
>
> On 15/03/2023 15:28, Kirill A. Shutemov wrote:
> > On Wed, Mar 15, 2023 at 02:18:52PM +0000, Tvrtko Ursulin wrote:
> > >
> > > On 15/03/2023 11:31, Kirill A. Shutemov wrote:
> > > > MAX_ORDER is not inclusive: the maximum allocation order buddy allocator
> > > > can deliver is MAX_ORDER-1.
> > >
> > > This looks to be true on inspection:
> > >
> > > __alloc_pages():
> > > ..
> > > if (WARN_ON_ONCE_GFP(order >= MAX_ORDER, gfp))
> > >
> > > So a bit of a misleading name "max".. For the i915 patch:
> > >
> > > Acked-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> > >
> > > I don't however see the whole series to understand the context, or how you
> > > want to handle the individual patches. Is it a tree wide cleanup of the same
> > > mistake?
> >
> > The whole patchset can be seen here:
> >
> > https://lore.kernel.org/all/20230315113133.11326-1-kirill.shutemov@xxxxxxxxxxxxxxx/
> >
> > The idea is to fix all MAX_ORDER bugs first and then re-define MAX_ORDER
> > more sensibly.
>
> Sounds good.
>
> Would you like i915 to take this patch or you will be bringing the whole lot
> via some other route? Former is okay and latter should also be fine for i915
> since I don't envisage any conflicts here.

I think would be better to get it via mm tree.

--
Kiryl Shutsemau / Kirill A. Shutemov