From: Matthew Brost <[email protected]>

The core MM splits the folio before calling folio_free, restoring the
zone pages associated with the folio to an initialized state (e.g.,
non-compound, pgmap valid, etc...). The order argument represents the
folio’s order prior to the split which can be used driver side to know
how many pages are being freed.

Fixes: 3a5a06554566 ("mm/zone_device: rename page_free callback to folio_free")
Cc: Zi Yan <[email protected]>
Cc: Madhavan Srinivasan <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: "Christophe Leroy (CS GROUP)" <[email protected]>
Cc: Felix Kuehling <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: "Christian König" <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Simona Vetter <[email protected]>
Cc: Maarten Lankhorst <[email protected]>
Cc: Maxime Ripard <[email protected]>
Cc: Thomas Zimmermann <[email protected]>
Cc: Lyude Paul <[email protected]>
Cc: Danilo Krummrich <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Logan Gunthorpe <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Leon Romanovsky <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Matthew Brost <[email protected]>
Signed-off-by: Francois Dugast <[email protected]>
---
 arch/powerpc/kvm/book3s_hv_uvmem.c       | 2 +-
 drivers/gpu/drm/amd/amdkfd/kfd_migrate.c | 2 +-
 drivers/gpu/drm/drm_pagemap.c            | 3 ++-
 drivers/gpu/drm/nouveau/nouveau_dmem.c   | 4 ++--
 drivers/pci/p2pdma.c                     | 2 +-
 include/linux/memremap.h                 | 7 ++++++-
 lib/test_hmm.c                           | 4 +---
 mm/memremap.c                            | 5 +++--
 8 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv_uvmem.c 
b/arch/powerpc/kvm/book3s_hv_uvmem.c
index e5000bef90f2..b58f34eec6e5 100644
--- a/arch/powerpc/kvm/book3s_hv_uvmem.c
+++ b/arch/powerpc/kvm/book3s_hv_uvmem.c
@@ -1014,7 +1014,7 @@ 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_folio_free(struct folio *folio)
+static void kvmppc_uvmem_folio_free(struct folio *folio, unsigned int order)
 {
        struct page *page = &folio->page;
        unsigned long pfn = page_to_pfn(page) -
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
index af53e796ea1b..a26e3c448e47 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -567,7 +567,7 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t 
best_loc,
        return r < 0 ? r : 0;
 }
 
-static void svm_migrate_folio_free(struct folio *folio)
+static void svm_migrate_folio_free(struct folio *folio, unsigned int order)
 {
        struct page *page = &folio->page;
        struct svm_range_bo *svm_bo = page->zone_device_data;
diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c
index 03ee39a761a4..df253b13cf85 100644
--- a/drivers/gpu/drm/drm_pagemap.c
+++ b/drivers/gpu/drm/drm_pagemap.c
@@ -1144,11 +1144,12 @@ static int __drm_pagemap_migrate_to_ram(struct 
vm_area_struct *vas,
 /**
  * drm_pagemap_folio_free() - Put GPU SVM zone device data associated with a 
folio
  * @folio: Pointer to the folio
+ * @order: Order of the folio prior to being split by core MM
  *
  * 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_folio_free(struct folio *folio)
+static void drm_pagemap_folio_free(struct folio *folio, unsigned int order)
 {
        drm_pagemap_zdd_put(folio->page.zone_device_data);
 }
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c 
b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index 58071652679d..545f316fca14 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c
@@ -115,14 +115,14 @@ unsigned long nouveau_dmem_page_addr(struct page *page)
        return chunk->bo->offset + off;
 }
 
-static void nouveau_dmem_folio_free(struct folio *folio)
+static void nouveau_dmem_folio_free(struct folio *folio, unsigned int order)
 {
        struct page *page = &folio->page;
        struct nouveau_dmem_chunk *chunk = nouveau_page_to_chunk(page);
        struct nouveau_dmem *dmem = chunk->drm->dmem;
 
        spin_lock(&dmem->lock);
-       if (folio_order(folio)) {
+       if (order) {
                page->zone_device_data = dmem->free_folios;
                dmem->free_folios = folio;
        } else {
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 4a2fc7ab42c3..a6fa7610f8a8 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -200,7 +200,7 @@ static const struct attribute_group p2pmem_group = {
        .name = "p2pmem",
 };
 
-static void p2pdma_folio_free(struct folio *folio)
+static void p2pdma_folio_free(struct folio *folio, unsigned int order)
 {
        struct page *page = &folio->page;
        struct pci_p2pdma_pagemap *pgmap = to_p2p_pgmap(page_pgmap(page));
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 713ec0435b48..97fcffeb1c1e 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -79,8 +79,13 @@ struct dev_pagemap_ops {
         * 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 folio again.
+        *
+        * The core MM splits the folio before calling folio_free, restoring the
+        * zone pages associated with the folio to an initialized state (e.g.,
+        * non-compound, pgmap valid, etc...). The order argument represents the
+        * folio’s order prior to the split.
         */
-       void (*folio_free)(struct folio *folio);
+       void (*folio_free)(struct folio *folio, unsigned int order);
 
        /*
         * Used for private (un-addressable) device memory only.  Must migrate
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 8af169d3873a..e17c71d02a3a 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -1580,13 +1580,11 @@ static const struct file_operations dmirror_fops = {
        .owner          = THIS_MODULE,
 };
 
-static void dmirror_devmem_free(struct folio *folio)
+static void dmirror_devmem_free(struct folio *folio, unsigned int order)
 {
        struct page *page = &folio->page;
        struct page *rpage = BACKING_PAGE(page);
        struct dmirror_device *mdevice;
-       struct folio *rfolio = page_folio(rpage);
-       unsigned int order = folio_order(rfolio);
 
        if (rpage != page) {
                if (order)
diff --git a/mm/memremap.c b/mm/memremap.c
index 63c6ab4fdf08..39dc4bd190d0 100644
--- a/mm/memremap.c
+++ b/mm/memremap.c
@@ -417,6 +417,7 @@ void free_zone_device_folio(struct folio *folio)
 {
        struct dev_pagemap *pgmap = folio->pgmap;
        unsigned long nr = folio_nr_pages(folio);
+       unsigned int order = folio_order(folio);
        int i;
 
        if (WARN_ON_ONCE(!pgmap))
@@ -453,7 +454,7 @@ void free_zone_device_folio(struct folio *folio)
        case MEMORY_DEVICE_COHERENT:
                if (WARN_ON_ONCE(!pgmap->ops || !pgmap->ops->folio_free))
                        break;
-               pgmap->ops->folio_free(folio);
+               pgmap->ops->folio_free(folio, order);
                percpu_ref_put_many(&folio->pgmap->ref, nr);
                break;
 
@@ -472,7 +473,7 @@ void free_zone_device_folio(struct folio *folio)
        case MEMORY_DEVICE_PCI_P2PDMA:
                if (WARN_ON_ONCE(!pgmap->ops || !pgmap->ops->folio_free))
                        break;
-               pgmap->ops->folio_free(folio);
+               pgmap->ops->folio_free(folio, order);
                break;
        }
 }
-- 
2.43.0


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