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    SubjectRe: [PATCH v5 05/38] drm: prime: use sgtable iterators in drm_prime_sg_to_page_addr_arrays()
    Hi Marek,

    On Tue, 22 Sep 2020, Marek Szyprowski wrote:

    > External email: Use caution opening links or attachments
    >
    >
    > Hi Alex,
    >
    > On 22.09.2020 01:15, Alex Goins wrote:
    > > Tested-by: Alex Goins <agoins@nvidia.com>
    > >
    > > This change fixes a regression with drm_prime_sg_to_page_addr_arrays() and
    > > AMDGPU in v5.9.
    >
    > Thanks for testing!
    >
    > > Commit 39913934 similarly revamped AMDGPU to use sgtable helper functions. When
    > > it changed from dma_map_sg_attrs() to dma_map_sgtable(), as a side effect it
    > > started correctly updating sgt->nents to the return value of dma_map_sg_attrs().
    > > However, drm_prime_sg_to_page_addr_arrays() incorrectly uses sgt->nents to
    > > iterate over pages, rather than sgt->orig_nents, resulting in it now returning
    > > the incorrect number of pages on AMDGPU.
    > >
    > > I had written a patch that changes drm_prime_sg_to_page_addr_arrays() to use
    > > for_each_sgtable_sg() instead of for_each_sg(), iterating using sgt->orig_nents:
    > >
    > > - for_each_sg(sgt->sgl, sg, sgt->nents, count) {
    > > + for_each_sgtable_sg(sgt, sg, count) {
    > >
    > > This patch takes it further, but still has the effect of fixing the number of
    > > pages that drm_prime_sg_to_page_addr_arrays() returns. Something like this
    > > should be included in v5.9 to prevent a regression with AMDGPU.
    >
    > Probably the easiest way to handle a fix for v5.9 would be to simply
    > merge the latest version of this patch also to v5.9-rcX:
    > https://lore.kernel.org/dri-devel/20200904131711.12950-3-m.szyprowski@samsung.com/

    Tested-by: Alex Goins <agoins@nvidia.com> that version too.

    >
    > This way we would get it fixed and avoid possible conflict in the -next.

    > Do you have any AMDGPU fixes for v5.9 in the queue? Maybe you can add that
    > patch to the queue?

    I don't have any more AMDGPU fixes, just want to ensure that this makes it in.

    Thanks,
    Alex

    > Dave: would it be okay that way?
    >
    > Best regards
    > --
    > Marek Szyprowski, PhD
    > Samsung R&D Institute Poland
    >
    >

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