[Intel-gfx] [PATCH] drm: Remove SCATTERLIST_MAX_SEGMENT

[Daniel Vetter]

On Thu, Oct 29, 2020 at 7:20 PM Jason Gunthorpe <jgg at nvidia.com> wrote:
>
> On Wed, Oct 28, 2020 at 08:49:11PM +0100, Daniel Vetter wrote:
> > On Wed, Oct 28, 2020 at 04:15:26PM -0300, Jason Gunthorpe wrote:
> > > Since commit 9a40401cfa13 ("lib/scatterlist: Do not limit max_segment to
> > > PAGE_ALIGNED values") the max_segment input to sg_alloc_table_from_pages()
> > > does not have to be any special value. The new algorithm will always
> > > create something less than what the user provides. Thus eliminate this
> > > confusing constant.
> > >
> > > - vmwgfx should use the HW capability, not mix in the OS page size for
> > >   calling dma_set_max_seg_size()
> > >
> > > - i915 uses i915_sg_segment_size() both for sg_alloc_table_from_pages
> > >   and for some open coded sgl construction. This doesn't change the value
> > >   since rounddown(size, UINT_MAX) == SCATTERLIST_MAX_SEGMENT
> > >
> > > - drm_prime_pages_to_sg uses it as a default if max_segment is zero,
> > >   UINT_MAX is fine to use directly.
> > >
> > > Cc: Gerd Hoffmann <kraxel at redhat.com>
> > > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > > Cc: Thomas Hellstrom <thellstrom at vmware.com>
> > > Cc: Qian Cai <cai at lca.pw>
> > > Cc: "Ursulin, Tvrtko" <tvrtko.ursulin at intel.com>
> > > Suggested-by: Christoph Hellwig <hch at lst.de>
> > > Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
> >
> > lgtm. Do you want to push this through some other queue, or should I put
> > this into drm trees? Prefer 5.10 or 5.11?
>
> I think DRM tree is best

Ok, I'll try to remember and apply this to -next after -rc2. -rc1 is
supremely busted for us, I want to wait with pulling the merge window
into the -next pile until that's settled. Please ping if your patch
isn't in linux-next within a week in case I forget.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch