Re: [PATCH v2 06/10] drm/gma500: Inline psb_gtt_attach_pages() and psb_gtt_detach_pages()

[Patrik Jakobsson <patrik.r.jakobsson@xxxxxxxxx>]

On Tue, Oct 5, 2021 at 10:11 AM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
>
> psb_gtt_attach_pages() are not GTT functions but deal with the GEM
> object's SHMEM pages. The only callers of psb_gtt_attach_pages() and
> psb_gtt_detach_pages() are the GEM pin helpers. Inline the calls and
> cleanup the resulting code.
>
> v2:
>         * unlock gtt_mutex in pin-error handling (Patrik)
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>

Acked-by: Patrik Jakobsson <patrik.r.jakobsson@xxxxxxxxx>


> ---
>  drivers/gpu/drm/gma500/gem.c | 94 ++++++++++++++++--------------------
>  1 file changed, 42 insertions(+), 52 deletions(-)
>
> diff --git a/drivers/gpu/drm/gma500/gem.c b/drivers/gpu/drm/gma500/gem.c
> index 1905468924ca..37b61334ade2 100644
> --- a/drivers/gpu/drm/gma500/gem.c
> +++ b/drivers/gpu/drm/gma500/gem.c
> @@ -19,63 +19,48 @@
>  #include "gem.h"
>  #include "psb_drv.h"
>
> -/*
> - * Pin and build an in-kernel list of the pages that back our GEM object.
> - * While we hold this the pages cannot be swapped out. This is protected
> - * via the gtt mutex which the caller must hold.
> - */
> -static int psb_gtt_attach_pages(struct gtt_range *gt)
> -{
> -       struct page **pages;
> -
> -       WARN_ON(gt->pages);
> -
> -       pages = drm_gem_get_pages(&gt->gem);
> -       if (IS_ERR(pages))
> -               return PTR_ERR(pages);
> -
> -       gt->npage = gt->gem.size / PAGE_SIZE;
> -       gt->pages = pages;
> -
> -       return 0;
> -}
> -
> -/*
> - * Undo the effect of psb_gtt_attach_pages. At this point the pages
> - * must have been removed from the GTT as they could now be paged out
> - * and move bus address. This is protected via the gtt mutex which the
> - * caller must hold.
> - */
> -static void psb_gtt_detach_pages(struct gtt_range *gt)
> -{
> -       drm_gem_put_pages(&gt->gem, gt->pages, true, false);
> -       gt->pages = NULL;
> -}
> -
>  int psb_gem_pin(struct gtt_range *gt)
>  {
>         int ret = 0;
>         struct drm_device *dev = gt->gem.dev;
>         struct drm_psb_private *dev_priv = to_drm_psb_private(dev);
>         u32 gpu_base = dev_priv->gtt.gatt_start;
> +       struct page **pages;
> +       unsigned int npages;
>
>         mutex_lock(&dev_priv->gtt_mutex);
>
> -       if (gt->in_gart == 0 && gt->stolen == 0) {
> -               ret = psb_gtt_attach_pages(gt);
> -               if (ret < 0)
> -                       goto out;
> -               ret = psb_gtt_insert(dev, gt, 0);
> -               if (ret < 0) {
> -                       psb_gtt_detach_pages(gt);
> -                       goto out;
> -               }
> -               psb_mmu_insert_pages(psb_mmu_get_default_pd(dev_priv->mmu),
> -                                    gt->pages, (gpu_base + gt->offset),
> -                                    gt->npage, 0, 0, PSB_MMU_CACHED_MEMORY);
> +       if (gt->in_gart || gt->stolen)
> +               goto out; /* already mapped */
> +
> +       pages = drm_gem_get_pages(&gt->gem);
> +       if (IS_ERR(pages)) {
> +               ret = PTR_ERR(pages);
> +               goto err_mutex_unlock;
>         }
> -       gt->in_gart++;
> +
> +       npages = gt->gem.size / PAGE_SIZE;
> +
> +       ret = psb_gtt_insert(dev, gt, 0);
> +       if (ret)
> +               goto err_drm_gem_put_pages;
> +
> +       psb_mmu_insert_pages(psb_mmu_get_default_pd(dev_priv->mmu), pages,
> +                            (gpu_base + gt->offset), npages, 0, 0,
> +                            PSB_MMU_CACHED_MEMORY);
> +
> +       gt->npage = npages;
> +       gt->pages = pages;
> +
>  out:
> +       ++gt->in_gart;
> +       mutex_unlock(&dev_priv->gtt_mutex);
> +
> +       return 0;
> +
> +err_drm_gem_put_pages:
> +       drm_gem_put_pages(&gt->gem, pages, true, false);
> +err_mutex_unlock:
>         mutex_unlock(&dev_priv->gtt_mutex);
>         return ret;
>  }
> @@ -90,14 +75,19 @@ void psb_gem_unpin(struct gtt_range *gt)
>
>         WARN_ON(!gt->in_gart);
>
> -       gt->in_gart--;
> -       if (gt->in_gart == 0 && gt->stolen == 0) {
> -               psb_mmu_remove_pages(psb_mmu_get_default_pd(dev_priv->mmu),
> +       --gt->in_gart;
> +
> +       if (gt->in_gart || gt->stolen)
> +               goto out;
> +
> +       psb_mmu_remove_pages(psb_mmu_get_default_pd(dev_priv->mmu),
>                                      (gpu_base + gt->offset), gt->npage, 0, 0);
> -               psb_gtt_remove(dev, gt);
> -               psb_gtt_detach_pages(gt);
> -       }
> +       psb_gtt_remove(dev, gt);
>
> +       drm_gem_put_pages(&gt->gem, gt->pages, true, false);
> +       gt->pages = NULL;
> +
> +out:
>         mutex_unlock(&dev_priv->gtt_mutex);
>  }
>
> --
> 2.33.0
>