From 2e03c0c5c59a086df534e15ddde03cb33bc475c4 Mon Sep 17 00:00:00 2001
From: Francois Dugast <francois.dugast@intel.com>
Date: Thu, 12 Mar 2026 20:20:12 +0100
Subject: drm/pagemap: Add helper to access zone_device_data

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.

v2:
- Move to drm_pagemap.h, stick to folio_zone_device_data (Matthew Brost)
- Return struct drm_pagemap_zdd * (Matthew Brost)

v3:
- Add stub for !CONFIG_ZONE_DEVICE (CI)

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: linux-mm@kvack.org
Suggested-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Francois Dugast <francois.dugast@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patch.msgid.link/20260312192126.2024853-3-francois.dugast@intel.com
---
 include/drm/drm_pagemap.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'include')

diff --git a/include/drm/drm_pagemap.h b/include/drm/drm_pagemap.h
index c848f578e3da..75e6ca58922d 100644
--- a/include/drm/drm_pagemap.h
+++ b/include/drm/drm_pagemap.h
@@ -4,6 +4,7 @@
 
 #include <linux/dma-direction.h>
 #include <linux/hmm.h>
+#include <linux/memremap.h>
 #include <linux/types.h>
 
 #define NR_PAGES(order) (1U << (order))
@@ -367,6 +368,26 @@ void drm_pagemap_destroy(struct drm_pagemap *dpagemap, bool is_atomic_or_reclaim
 
 int drm_pagemap_reinit(struct drm_pagemap *dpagemap);
 
+/**
+ * drm_pagemap_page_zone_device_data() - Page to zone_device_data
+ * @page: Pointer to the page
+ *
+ * Return: Page's zone_device_data
+ */
+static inline struct drm_pagemap_zdd *drm_pagemap_page_zone_device_data(struct page *page)
+{
+	struct folio *folio = page_folio(page);
+
+	return folio_zone_device_data(folio);
+}
+
+#else
+
+static inline struct drm_pagemap_zdd *drm_pagemap_page_zone_device_data(struct page *page)
+{
+	return NULL;
+}
+
 #endif /* IS_ENABLED(CONFIG_ZONE_DEVICE) */
 
 #endif
-- 
cgit v1.2.3