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);
> +
I think we can actually just do:
return folio_zone_device_data(folio)
We still need the helper as if page is part of a folio the individual
page->zone_device_data could be NULL.
Also since this called from GPU SVM maybe make this an inline in
drm_pagemap.h too. We'd have to include 'linux/memremap.h' in
drm_pagemap.h but I don't that is a huge deal.
Matt
> + 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);
> +
> #endif
> --
> 2.43.0
>
