linux-kernel - Re: [PATCH v2 26/37] drm/i915/gem: drop nth

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Message-ID: <22019944-2ef2-4463-9b3f-23c9e7c70b2f@redhat.com>
Date: Tue, 2 Sep 2025 11:42:30 +0200
From: David Hildenbrand <david@...hat.com>
To: Tvrtko Ursulin <tursulin@...ulin.net>, linux-kernel@...r.kernel.org
Cc: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
 Jani Nikula <jani.nikula@...ux.intel.com>,
 Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
 Rodrigo Vivi <rodrigo.vivi@...el.com>, David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>, Alexander Potapenko <glider@...gle.com>,
 Andrew Morton <akpm@...ux-foundation.org>,
 Brendan Jackman <jackmanb@...gle.com>, Christoph Lameter <cl@...two.org>,
 Dennis Zhou <dennis@...nel.org>, Dmitry Vyukov <dvyukov@...gle.com>,
 dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
 iommu@...ts.linux.dev, io-uring@...r.kernel.org,
 Jason Gunthorpe <jgg@...dia.com>, Jens Axboe <axboe@...nel.dk>,
 Johannes Weiner <hannes@...xchg.org>, John Hubbard <jhubbard@...dia.com>,
 kasan-dev@...glegroups.com, kvm@...r.kernel.org,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>,
 Linus Torvalds <torvalds@...ux-foundation.org>, linux-arm-kernel@...s.com,
 linux-arm-kernel@...ts.infradead.org, linux-crypto@...r.kernel.org,
 linux-ide@...r.kernel.org, linux-kselftest@...r.kernel.org,
 linux-mips@...r.kernel.org, linux-mmc@...r.kernel.org, linux-mm@...ck.org,
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Subject: Re: [PATCH v2 26/37] drm/i915/gem: drop nth_page() usage within SG
 entry

On 02.09.25 11:22, Tvrtko Ursulin wrote:
> 
> On 01/09/2025 16:03, David Hildenbrand wrote:
>> It's no longer required to use nth_page() when iterating pages within a
>> single SG entry, so let's drop the nth_page() usage.
>>
>> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
>> Cc: Jani Nikula <jani.nikula@...ux.intel.com>
>> Cc: Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>
>> Cc: Rodrigo Vivi <rodrigo.vivi@...el.com>
>> Cc: Tvrtko Ursulin <tursulin@...ulin.net>
>> Cc: David Airlie <airlied@...il.com>
>> Cc: Simona Vetter <simona@...ll.ch>
>> Signed-off-by: David Hildenbrand <david@...hat.com>
>> ---
>>    drivers/gpu/drm/i915/gem/i915_gem_pages.c | 2 +-
>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
>> index c16a57160b262..031d7acc16142 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
>> @@ -779,7 +779,7 @@ __i915_gem_object_get_page(struct drm_i915_gem_object *obj, pgoff_t n)
>>    	GEM_BUG_ON(!i915_gem_object_has_struct_page(obj));
>>    
>>    	sg = i915_gem_object_get_sg(obj, n, &offset);
>> -	return nth_page(sg_page(sg), offset);
>> +	return sg_page(sg) + offset;
>>    }
>>    
>>    /* Like i915_gem_object_get_page(), but mark the returned page dirty */
> 
> LGTM. If you want an ack to merge via a tree other than i915 you have
> it. I suspect it might be easier to coordinate like that.

Yeah, it would be best to route all of that through the MM tree. Thanks!

-- 
Cheers

David / dhildenb