On Tue, Dec 16, 2025 at 09:10:13PM +0100, Francois Dugast wrote:
> This new helper helps ensure all accesses to zone_device_data use the
> correct API whether the page is part of a folio or not.
> 
> Suggested-by: Matthew Brost <[email protected]>
> Signed-off-by: Francois Dugast <[email protected]>
> ---
>  drivers/gpu/drm/drm_gpusvm.c  |  7 +++++--
>  drivers/gpu/drm/drm_pagemap.c | 32 +++++++++++++++++++++++++-------
>  include/drm/drm_pagemap.h     |  2 ++
>  3 files changed, 32 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c
> index 39c8c50401dd..d0ff6b65e543 100644
> --- a/drivers/gpu/drm/drm_gpusvm.c
> +++ b/drivers/gpu/drm/drm_gpusvm.c
> @@ -1366,12 +1366,15 @@ int drm_gpusvm_get_pages(struct drm_gpusvm *gpusvm,
>               order = drm_gpusvm_hmm_pfn_to_order(pfns[i], i, npages);
>               if (is_device_private_page(page) ||
>                   is_device_coherent_page(page)) {
> +                     struct drm_pagemap_zdd *__zdd =
> +                             drm_pagemap_page_zone_device_data(page);
> +
>                       if (!ctx->allow_mixed &&
> -                         zdd != page->zone_device_data && i > 0) {
> +                         zdd != __zdd && i > 0) {
>                               err = -EOPNOTSUPP;
>                               goto err_unmap;
>                       }
> -                     zdd = page->zone_device_data;
> +                     zdd = __zdd;
>                       if (pagemap != page_pgmap(page)) {
>                               if (i > 0) {
>                                       err = -EOPNOTSUPP;
> diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c
> index 491de9275add..b71e47136112 100644
> --- a/drivers/gpu/drm/drm_pagemap.c
> +++ b/drivers/gpu/drm/drm_pagemap.c
> @@ -192,6 +192,22 @@ static void 
> drm_pagemap_migration_unlock_put_pages(unsigned long npages,
>       }
>  }
>  
> +/**
> + * drm_pagemap_page_zone_device_data() - Page to zone_device_data
> + * @page: Pointer to the page
> + *
> + * Return: Page's zone_device_data
> + */
> +void *drm_pagemap_page_zone_device_data(struct page *page)
> +{
> +     struct folio *folio = page_folio(page);
> +
> +     if (folio_order(folio))
> +             return folio_zone_device_data(folio);
> +
> +     return page->zone_device_data;
> +}
> +
>  /**
>   * drm_pagemap_get_devmem_page() - Get a reference to a device memory page
>   * @page: Pointer to the page
> @@ -481,8 +497,8 @@ static int drm_pagemap_migrate_populate_ram_pfn(struct 
> vm_area_struct *vas,
>                       goto next;
>  
>               if (fault_page) {
> -                     if (src_page->zone_device_data !=
> -                         fault_page->zone_device_data)
> +                     if (drm_pagemap_page_zone_device_data(src_page) !=
> +                         drm_pagemap_page_zone_device_data(fault_page))
>                               goto next;
>               }
>  
> @@ -670,7 +686,7 @@ static int __drm_pagemap_migrate_to_ram(struct 
> vm_area_struct *vas,
>       int i, err = 0;
>  
>       if (page) {
> -             zdd = page->zone_device_data;
> +             zdd = drm_pagemap_page_zone_device_data(page);
>               if (time_before64(get_jiffies_64(),
>                                 zdd->devmem_allocation->timeslice_expiration))
>                       return 0;
> @@ -722,7 +738,7 @@ static int __drm_pagemap_migrate_to_ram(struct 
> vm_area_struct *vas,
>               if (!page)
>                       goto err_finalize;
>       }
> -     zdd = page->zone_device_data;
> +     zdd = drm_pagemap_page_zone_device_data(page);
>       ops = zdd->devmem_allocation->ops;
>       dev = zdd->devmem_allocation->dev;
>  
> @@ -768,7 +784,9 @@ static int __drm_pagemap_migrate_to_ram(struct 
> vm_area_struct *vas,
>   */
>  static void drm_pagemap_folio_free(struct folio *folio)
>  {
> -     drm_pagemap_zdd_put(folio->page.zone_device_data);
> +     struct page *page = folio_page(folio, 0);
> +
> +     drm_pagemap_zdd_put(drm_pagemap_page_zone_device_data(page));
>  }
>  
>  /**
> @@ -784,7 +802,7 @@ static void drm_pagemap_folio_free(struct folio *folio)
>   */
>  static vm_fault_t drm_pagemap_migrate_to_ram(struct vm_fault *vmf)
>  {
> -     struct drm_pagemap_zdd *zdd = vmf->page->zone_device_data;
> +     struct drm_pagemap_zdd *zdd = 
> drm_pagemap_page_zone_device_data(vmf->page);
>       int err;
>  
>       err = __drm_pagemap_migrate_to_ram(vmf->vma,
> @@ -847,7 +865,7 @@ EXPORT_SYMBOL_GPL(drm_pagemap_devmem_init);
>   */
>  struct drm_pagemap *drm_pagemap_page_to_dpagemap(struct page *page)
>  {
> -     struct drm_pagemap_zdd *zdd = page->zone_device_data;
> +     struct drm_pagemap_zdd *zdd = drm_pagemap_page_zone_device_data(page);
>  
>       return zdd->devmem_allocation->dpagemap;
>  }
> diff --git a/include/drm/drm_pagemap.h b/include/drm/drm_pagemap.h
> index f6e7e234c089..3a8d0e1cef43 100644
> --- a/include/drm/drm_pagemap.h
> +++ b/include/drm/drm_pagemap.h
> @@ -245,4 +245,6 @@ int drm_pagemap_populate_mm(struct drm_pagemap *dpagemap,
>                           struct mm_struct *mm,
>                           unsigned long timeslice_ms);
>  
> +void *drm_pagemap_page_zone_device_data(struct page *page);

I missed this in my previous reply:

s/void */struct drm_pagemap_zdd */

Matt

> +
>  #endif
> -- 
> 2.43.0
> 

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