mm/zone_device: rename page_free callback to folio_free

Change page_free to folio_free to make the folio support for
zone device-private more consistent. The PCI P2PDMA callback
has also been updated and changed to folio_free() as a result.

For drivers that do not support folios (yet), the folio is
converted back into page via &folio->page and the page is used
as is, in the current callback implementation.

Link: https://lkml.kernel.org/r/20251001065707.920170-3-balbirs@nvidia.com
Signed-off-by: Balbir Singh <balbirs@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Airlie <airlied@gmail.com>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Francois Dugast <francois.dugast@intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Documentation/mm/memory-model.rst

@@ -165,7 +165,7 @@ The users of `ZONE_DEVICE` are:
 * pmem: Map platform persistent memory to be used as a direct-I/O target
   via DAX mappings.
 
-* hmm: Extend `ZONE_DEVICE` with `->page_fault()` and `->page_free()`
+* hmm: Extend `ZONE_DEVICE` with `->page_fault()` and `->folio_free()`
   event callbacks to allow a device-driver to coordinate memory management
   events related to device-memory, typically GPU memory. See
   Documentation/mm/hmm.rst.

arch/powerpc/kvm/book3s_hv_uvmem.c

@@ -1014,8 +1014,9 @@ static vm_fault_t kvmppc_uvmem_migrate_to_ram(struct vm_fault *vmf)
  * to a normal PFN during H_SVM_PAGE_OUT.
  * Gets called with kvm->arch.uvmem_lock held.
  */
-static void kvmppc_uvmem_page_free(struct page *page)
+static void kvmppc_uvmem_folio_free(struct folio *folio)
 {
+	struct page *page = &folio->page;
 	unsigned long pfn = page_to_pfn(page) -
 			(kvmppc_uvmem_pgmap.range.start >> PAGE_SHIFT);
 	struct kvmppc_uvmem_page_pvt *pvt;
@@ -1034,7 +1035,7 @@ static void kvmppc_uvmem_page_free(struct page *page)
 }
 
 static const struct dev_pagemap_ops kvmppc_uvmem_ops = {
-	.page_free = kvmppc_uvmem_page_free,
+	.folio_free = kvmppc_uvmem_folio_free,
 	.migrate_to_ram	= kvmppc_uvmem_migrate_to_ram,
 };
 

drivers/gpu/drm/amd/amdkfd/kfd_migrate.c

@@ -568,8 +568,9 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
 	return r < 0 ? r : 0;
 }
 
-static void svm_migrate_page_free(struct page *page)
+static void svm_migrate_folio_free(struct folio *folio)
 {
+	struct page *page = &folio->page;
 	struct svm_range_bo *svm_bo = page->zone_device_data;
 
 	if (svm_bo) {
@@ -1009,7 +1010,7 @@ static vm_fault_t svm_migrate_to_ram(struct vm_fault *vmf)
 }
 
 static const struct dev_pagemap_ops svm_migrate_pgmap_ops = {
-	.page_free		= svm_migrate_page_free,
+	.folio_free		= svm_migrate_folio_free,
 	.migrate_to_ram		= svm_migrate_to_ram,
 };
 

drivers/gpu/drm/drm_pagemap.c

@@ -752,15 +752,15 @@ static int __drm_pagemap_migrate_to_ram(struct vm_area_struct *vas,
 }
 
 /**
- * drm_pagemap_page_free() - Put GPU SVM zone device data associated with a page
- * @page: Pointer to the page
+ * drm_pagemap_folio_free() - Put GPU SVM zone device data associated with a folio
+ * @folio: Pointer to the folio
  *
  * This function is a callback used to put the GPU SVM zone device data
  * associated with a page when it is being released.
  */
-static void drm_pagemap_page_free(struct page *page)
+static void drm_pagemap_folio_free(struct folio *folio)
 {
-	drm_pagemap_zdd_put(page->zone_device_data);
+	drm_pagemap_zdd_put(folio->page.zone_device_data);
 }
 
 /**
@@ -788,7 +788,7 @@ static vm_fault_t drm_pagemap_migrate_to_ram(struct vm_fault *vmf)
 }
 
 static const struct dev_pagemap_ops drm_pagemap_pagemap_ops = {
-	.page_free = drm_pagemap_page_free,
+	.folio_free = drm_pagemap_folio_free,
 	.migrate_to_ram = drm_pagemap_migrate_to_ram,
 };
 

drivers/gpu/drm/nouveau/nouveau_dmem.c

@@ -108,8 +108,9 @@ unsigned long nouveau_dmem_page_addr(struct page *page)
 	return chunk->bo->offset + off;
 }
 
-static void nouveau_dmem_page_free(struct page *page)
+static void nouveau_dmem_folio_free(struct folio *folio)
 {
+	struct page *page = &folio->page;
 	struct nouveau_dmem_chunk *chunk = nouveau_page_to_chunk(page);
 	struct nouveau_dmem *dmem = chunk->drm->dmem;
 
@@ -220,7 +221,7 @@ static vm_fault_t nouveau_dmem_migrate_to_ram(struct vm_fault *vmf)
 }
 
 static const struct dev_pagemap_ops nouveau_dmem_pagemap_ops = {
-	.page_free		= nouveau_dmem_page_free,
+	.folio_free		= nouveau_dmem_folio_free,
 	.migrate_to_ram		= nouveau_dmem_migrate_to_ram,
 };
 

drivers/pci/p2pdma.c

@@ -200,8 +200,9 @@ static const struct attribute_group p2pmem_group = {
 	.name = "p2pmem",
 };
 
-static void p2pdma_page_free(struct page *page)
+static void p2pdma_folio_free(struct folio *folio)
 {
+	struct page *page = &folio->page;
 	struct pci_p2pdma_pagemap *pgmap = to_p2p_pgmap(page_pgmap(page));
 	/* safe to dereference while a reference is held to the percpu ref */
 	struct pci_p2pdma *p2pdma =
@@ -214,7 +215,7 @@ static void p2pdma_page_free(struct page *page)
 }
 
 static const struct dev_pagemap_ops p2pdma_pgmap_ops = {
-	.page_free = p2pdma_page_free,
+	.folio_free = p2pdma_folio_free,
 };
 
 static void pci_p2pdma_release(void *data)

include/linux/memremap.h

@@ -77,11 +77,11 @@ enum memory_type {
 
 struct dev_pagemap_ops {
 	/*
-	 * Called once the page refcount reaches 0.  The reference count will be
+	 * Called once the folio refcount reaches 0.  The reference count will be
 	 * reset to one by the core code after the method is called to prepare
-	 * for handing out the page again.
+	 * for handing out the folio again.
 	 */
-	void (*page_free)(struct page *page);
+	void (*folio_free)(struct folio *folio);
 
 	/*
 	 * Used for private (un-addressable) device memory only.  Must migrate

lib/test_hmm.c

@@ -1374,8 +1374,9 @@ static const struct file_operations dmirror_fops = {
 	.owner		= THIS_MODULE,
 };
 
-static void dmirror_devmem_free(struct page *page)
+static void dmirror_devmem_free(struct folio *folio)
 {
+	struct page *page = &folio->page;
 	struct page *rpage = BACKING_PAGE(page);
 	struct dmirror_device *mdevice;
 
@@ -1438,7 +1439,7 @@ static vm_fault_t dmirror_devmem_fault(struct vm_fault *vmf)
 }
 
 static const struct dev_pagemap_ops dmirror_devmem_ops = {
-	.page_free	= dmirror_devmem_free,
+	.folio_free	= dmirror_devmem_free,
 	.migrate_to_ram	= dmirror_devmem_fault,
 };
 

mm/memremap.c

@@ -289,8 +289,8 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 			WARN(1, "Missing migrate_to_ram method\n");
 			return ERR_PTR(-EINVAL);
 		}
-		if (!pgmap->ops->page_free) {
-			WARN(1, "Missing page_free method\n");
+		if (!pgmap->ops->folio_free) {
+			WARN(1, "Missing folio_free method\n");
 			return ERR_PTR(-EINVAL);
 		}
 		if (!pgmap->owner) {
@@ -299,8 +299,8 @@ void *memremap_pages(struct dev_pagemap *pgmap, int nid)
 		}
 		break;
 	case MEMORY_DEVICE_COHERENT:
-		if (!pgmap->ops->page_free) {
-			WARN(1, "Missing page_free method\n");
+		if (!pgmap->ops->folio_free) {
+			WARN(1, "Missing folio_free method\n");
 			return ERR_PTR(-EINVAL);
 		}
 		if (!pgmap->owner) {
@@ -453,9 +453,9 @@ void free_zone_device_folio(struct folio *folio)
 	switch (pgmap->type) {
 	case MEMORY_DEVICE_PRIVATE:
 	case MEMORY_DEVICE_COHERENT:
-		if (WARN_ON_ONCE(!pgmap->ops || !pgmap->ops->page_free))
+		if (WARN_ON_ONCE(!pgmap->ops || !pgmap->ops->folio_free))
 			break;
-		pgmap->ops->page_free(&folio->page);
+		pgmap->ops->folio_free(folio);
 		percpu_ref_put_many(&folio->pgmap->ref, nr);
 		break;
 
@@ -472,9 +472,9 @@ void free_zone_device_folio(struct folio *folio)
 		break;
 
 	case MEMORY_DEVICE_PCI_P2PDMA:
-		if (WARN_ON_ONCE(!pgmap->ops || !pgmap->ops->page_free))
+		if (WARN_ON_ONCE(!pgmap->ops || !pgmap->ops->folio_free))
 			break;
-		pgmap->ops->page_free(folio_page(folio, 0));
+		pgmap->ops->folio_free(folio);
 		break;
 	}
 }