Message-ID: <20251001065707.920170-3-balbirs@nvidia.com>
Date: Wed,  1 Oct 2025 16:56:53 +1000
From: Balbir Singh <balbirs@...dia.com>
To: linux-kernel@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	linux-mm@...ck.org
Cc: akpm@...ux-foundation.org,
	Balbir Singh <balbirs@...dia.com>,
	David Hildenbrand <david@...hat.com>,
	Zi Yan <ziy@...dia.com>,
	Joshua Hahn <joshua.hahnjy@...il.com>,
	Rakie Kim <rakie.kim@...com>,
	Byungchul Park <byungchul@...com>,
	Gregory Price <gourry@...rry.net>,
	Ying Huang <ying.huang@...ux.alibaba.com>,
	Alistair Popple <apopple@...dia.com>,
	Oscar Salvador <osalvador@...e.de>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	Baolin Wang <baolin.wang@...ux.alibaba.com>,
	"Liam R. Howlett" <Liam.Howlett@...cle.com>,
	Nico Pache <npache@...hat.com>,
	Ryan Roberts <ryan.roberts@....com>,
	Dev Jain <dev.jain@....com>,
	Barry Song <baohua@...nel.org>,
	Lyude Paul <lyude@...hat.com>,
	Danilo Krummrich <dakr@...nel.org>,
	David Airlie <airlied@...il.com>,
	Simona Vetter <simona@...ll.ch>,
	Ralph Campbell <rcampbell@...dia.com>,
	Mika Penttilä <mpenttil@...hat.com>,
	Matthew Brost <matthew.brost@...el.com>,
	Francois Dugast <francois.dugast@...el.com>,
	Madhavan Srinivasan <maddy@...ux.ibm.com>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	Felix Kuehling <Felix.Kuehling@....com>,
	Alex Deucher <alexander.deucher@....com>,
	Christian König <christian.koenig@....com>
Subject: [v7 02/16] 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.

Cc: David Hildenbrand <david@...hat.com>
Cc: Zi Yan <ziy@...dia.com>
Cc: Joshua Hahn <joshua.hahnjy@...il.com>
Cc: Rakie Kim <rakie.kim@...com>
Cc: Byungchul Park <byungchul@...com>
Cc: Gregory Price <gourry@...rry.net>
Cc: Ying Huang <ying.huang@...ux.alibaba.com>
Cc: Alistair Popple <apopple@...dia.com>
Cc: Oscar Salvador <osalvador@...e.de>
Cc: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Cc: Baolin Wang <baolin.wang@...ux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@...cle.com>
Cc: Nico Pache <npache@...hat.com>
Cc: Ryan Roberts <ryan.roberts@....com>
Cc: Dev Jain <dev.jain@....com>
Cc: Barry Song <baohua@...nel.org>
Cc: Lyude Paul <lyude@...hat.com>
Cc: Danilo Krummrich <dakr@...nel.org>
Cc: David Airlie <airlied@...il.com>
Cc: Simona Vetter <simona@...ll.ch>
Cc: Ralph Campbell <rcampbell@...dia.com>
Cc: Mika Penttilä <mpenttil@...hat.com>
Cc: Matthew Brost <matthew.brost@...el.com>
Cc: Francois Dugast <francois.dugast@...el.com>
Cc: Madhavan Srinivasan <maddy@...ux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@...roup.eu>
Cc: Felix Kuehling <Felix.Kuehling@....com>
Cc: Alex Deucher <alexander.deucher@....com>
Cc: "Christian König" <christian.koenig@....com>
Cc: Andrew Morton <akpm@...ux-foundation.org>

Signed-off-by: Balbir Singh <balbirs@...dia.com>
---
 Documentation/mm/memory-model.rst        |  2 +-
 arch/powerpc/kvm/book3s_hv_uvmem.c       |  5 +++--
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c |  5 +++--
 drivers/gpu/drm/drm_pagemap.c            | 10 +++++-----
 drivers/gpu/drm/nouveau/nouveau_dmem.c   |  5 +++--
 drivers/pci/p2pdma.c                     |  5 +++--
 include/linux/memremap.h                 |  6 +++---
 lib/test_hmm.c                           |  5 +++--
 mm/memremap.c                            | 16 ++++++++--------
 9 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/Documentation/mm/memory-model.rst b/Documentation/mm/memory-model.rst
index 5f3eafbbc520..7957122039e8 100644
--- a/Documentation/mm/memory-model.rst
+++ b/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.
diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c b/arch/powerpc/kvm/book3s_hv_uvmem.c
index 91f763410673..e5000bef90f2 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/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,
 };
 
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index d0e2cae33035..e5203764287b 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -567,8 +567,9 @@ 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) {
@@ -1008,7 +1009,7 @@ 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,
 };
 
diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c
index 31c53f724e25..1bd949df2fe8 100644
--- a/drivers/gpu/drm/drm_pagemap.c
+++ b/drivers/gpu/drm/drm_pagemap.c
@@ -708,15 +708,15 @@ 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);
 }
 
 /**
@@ -744,7 +744,7 @@ 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,
 };
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index 53cc1926b9da..d34288ebe7d2 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/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,
 };
 
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index da5657a02007..8515b3bfdfdf 100644
--- a/drivers/pci/p2pdma.c
+++ b/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)
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index d2487a19cba2..cd28d1666801 100644
--- a/include/linux/memremap.h
+++ b/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
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 24d82121cde8..9dbf265d1036 100644
--- a/lib/test_hmm.c
+++ b/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,
 };
 
diff --git a/mm/memremap.c b/mm/memremap.c
index e45dfb568710..4c2e0d68eb27 100644
--- a/mm/memremap.c
+++ b/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;
 	}
 }
-- 
2.51.0

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