linux-kernel - Re: [PATCH v9 11/32] drm: mediatek: use common helper for extracting pages array

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Date:   Wed, 2 Sep 2020 07:16:54 +0800
From:   Chun-Kuang Hu <chunkuang.hu@...nel.org>
To:     Robin Murphy <robin.murphy@....com>
Cc:     Marek Szyprowski <m.szyprowski@...sung.com>,
        DRI Development <dri-devel@...ts.freedesktop.org>,
        iommu@...ts.linux-foundation.org, linaro-mm-sig@...ts.linaro.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Christoph Hellwig <hch@....de>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>
Subject: Re: [PATCH v9 11/32] drm: mediatek: use common helper for extracting
 pages array

Robin Murphy <robin.murphy@....com> 於 2020年9月2日 週三 上午2:55寫道：
>
> On 2020-08-26 07:32, Marek Szyprowski wrote:
> > Use common helper for converting a sg_table object into struct
> > page pointer array.
>
> Reviewed-by: Robin Murphy <robin.murphy@....com>
>
> Side note: is mtk_drm_gem_prime_vmap() missing a call to
> sg_free_table(sgt) before its kfree(sgt)?

Yes, we need another patch to fix that bug, But for this patch,

Acked-by: Chun-Kuang Hu <chunkuang.hu@...nel.org>

>
> > Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
> > ---
> >   drivers/gpu/drm/mediatek/mtk_drm_gem.c | 9 ++-------
> >   1 file changed, 2 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_gem.c b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > index 3654ec732029..0583e557ad37 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_gem.c
> > @@ -233,9 +233,7 @@ void *mtk_drm_gem_prime_vmap(struct drm_gem_object *obj)
> >   {
> >       struct mtk_drm_gem_obj *mtk_gem = to_mtk_gem_obj(obj);
> >       struct sg_table *sgt;
> > -     struct sg_page_iter iter;
> >       unsigned int npages;
> > -     unsigned int i = 0;
> >
> >       if (mtk_gem->kvaddr)
> >               return mtk_gem->kvaddr;
> > @@ -249,11 +247,8 @@ void *mtk_drm_gem_prime_vmap(struct drm_gem_object *obj)
> >       if (!mtk_gem->pages)
> >               goto out;
> >
> > -     for_each_sg_page(sgt->sgl, &iter, sgt->orig_nents, 0) {
> > -             mtk_gem->pages[i++] = sg_page_iter_page(&iter);
> > -             if (i > npages)
> > -                     break;
> > -     }
> > +     drm_prime_sg_to_page_addr_arrays(sgt, mtk_gem->pages, NULL, npages);
> > +
> >       mtk_gem->kvaddr = vmap(mtk_gem->pages, npages, VM_MAP,
> >                              pgprot_writecombine(PAGE_KERNEL));
> >
> >