[to-be-updated] mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping.patch removed from -mm tree

[to-be-updated] mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping.patch removed from -mm tree

[Andrew Morton]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 21956 bytes --]


The quilt patch titled
     Subject: mm: provide vma_[flags_]is_cow_mapping() and remove is_cow_mapping()
has been removed from the -mm tree.  Its filename was
     mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Subject: mm: provide vma_[flags_]is_cow_mapping() and remove is_cow_mapping()
Date: Thu, 06 Aug 2026 21:21:27 +0100

All remaining callers of is_cow_mapping() are invoking it in the form of
is_cow_mapping(vma->vm_flags) or an indirected version of this.

Therefore, provide a helper - vma_is_cow_mapping() to directly test the
VMA.

Additionally provide a new helper vma_flags_is_cow_mapping() which
performs the check using the new vma_flags_t type, and share this logic
between vma_is_cow_mapping() and vma_desc_is_cow_mapping().

With these changes, no callers of is_cow_mapping() remain, so remove it.

Also update the userland VMA tests to reflect the change.

No functional change intended.

[akpm@linux-foundation.org: add comments, per Lorenzo]
  Link: https://lore.kernel.org/ann-vS6MYT9kuXqu@lucifer
[akpm@linux-foundation.org: fix kerneldoc]
  Closes: https://lore.kernel.org/e7911812-9b99-4f94-be6b-597bf202ffeb@infradead.org
Link: https://lore.kernel.org/20260806-b4-scalable-cow-virt-pgoff-v4-2-ab318a350404@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: Boris Brezillon <boris.brezillon@collabora.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christan König <christian.koenig@amd.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price (Meta) <gourry@gourry.net>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huang Ray <Ray.Huang@amd.com>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: <syzbot@syzkaller.appspotmail.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Xu Xin <xu.xin16@zte.com.cn>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/s390/mm/gmap_helpers.c             |    2 
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c |    4 -
 drivers/gpu/drm/drm_gem_shmem_helper.c  |    2 
 drivers/gpu/drm/panthor/panthor_gem.c   |    2 
 drivers/gpu/drm/ttm/ttm_bo_vm.c         |    2 
 drivers/gpu/drm/xe/xe_device.c          |    2 
 fs/proc/task_mmu.c                      |    2 
 include/linux/mm.h                      |   72 ++++++++++++++++++++--
 kernel/events/uprobes.c                 |    2 
 mm/gup.c                                |    2 
 mm/huge_memory.c                        |    8 +-
 mm/hugetlb.c                            |    2 
 mm/internal.h                           |    2 
 mm/memory.c                             |   25 +++----
 mm/mempolicy.c                          |    2 
 tools/testing/vma/include/dup.h         |   11 +++
 16 files changed, 106 insertions(+), 36 deletions(-)

--- a/arch/s390/mm/gmap_helpers.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/arch/s390/mm/gmap_helpers.c
@@ -200,7 +200,7 @@ static int find_zeropage_pte_entry(pte_t
 		 * currently only works in COW mappings, which is also where
 		 * mm_forbids_zeropage() is checked.
 		 */
-		if (!is_cow_mapping(walk->vma->vm_flags))
+		if (!vma_is_cow_mapping(walk->vma))
 			return -EFAULT;
 
 		*found_addr = addr;
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -377,9 +377,9 @@ static int amdgpu_gem_object_mmap(struct
 	/* Workaround for Thunk bug creating PROT_NONE,MAP_PRIVATE mappings
 	 * for debugger access to invisible VRAM. Should have used MAP_SHARED
 	 * instead. Clearing VM_MAYWRITE prevents the mapping from ever
-	 * becoming writable and makes is_cow_mapping(vm_flags) false.
+	 * becoming writable and makes vma_is_cow_mapping(vma) false.
 	 */
-	if (is_cow_mapping(vma->vm_flags) &&
+	if (vma_is_cow_mapping(vma) &&
 	    !(vma->vm_flags & VM_ACCESS_FLAGS))
 		vm_flags_clear(vma, VM_MAYWRITE);
 
--- a/drivers/gpu/drm/drm_gem_shmem_helper.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/drivers/gpu/drm/drm_gem_shmem_helper.c
@@ -753,7 +753,7 @@ int drm_gem_shmem_mmap(struct drm_gem_sh
 		return ret;
 	}
 
-	if (is_cow_mapping(vma->vm_flags))
+	if (vma_is_cow_mapping(vma))
 		return -EINVAL;
 
 	dma_resv_lock(shmem->base.resv, NULL);
--- a/drivers/gpu/drm/panthor/panthor_gem.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/drivers/gpu/drm/panthor/panthor_gem.c
@@ -761,7 +761,7 @@ static int panthor_gem_mmap(struct drm_g
 		return ret;
 	}
 
-	if (is_cow_mapping(vma->vm_flags))
+	if (vma_is_cow_mapping(vma))
 		return -EINVAL;
 
 	if (!refcount_inc_not_zero(&bo->cmap.mmap_count)) {
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -489,7 +489,7 @@ static const struct vm_operations_struct
 int ttm_bo_mmap_obj(struct vm_area_struct *vma, struct ttm_buffer_object *bo)
 {
 	/* Enforce no COW since would have really strange behavior with it. */
-	if (is_cow_mapping(vma->vm_flags))
+	if (vma_is_cow_mapping(vma))
 		return -EINVAL;
 
 	drm_gem_object_get(&bo->base);
--- a/drivers/gpu/drm/xe/xe_device.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/drivers/gpu/drm/xe/xe_device.c
@@ -330,7 +330,7 @@ static int xe_pci_barrier_mmap(struct fi
 	if (vma->vm_end - vma->vm_start > SZ_4K)
 		return -EINVAL;
 
-	if (is_cow_mapping(vma->vm_flags))
+	if (vma_is_cow_mapping(vma))
 		return -EINVAL;
 
 	if (vma->vm_flags & (VM_READ | VM_EXEC))
--- a/fs/proc/task_mmu.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/fs/proc/task_mmu.c
@@ -1693,7 +1693,7 @@ static inline bool pte_is_pinned(struct
 
 	if (!pte_write(pte))
 		return false;
-	if (!is_cow_mapping(vma->vm_flags))
+	if (!vma_is_cow_mapping(vma))
 		return false;
 	if (likely(!mm_flags_test(MMF_HAS_PINNED, vma->vm_mm)))
 		return false;
--- a/include/linux/mm.h~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/include/linux/mm.h
@@ -2271,17 +2271,77 @@ void unpin_user_pages(struct page **page
 void unpin_user_folio(struct folio *folio, unsigned long npages);
 void unpin_folios(struct folio **folios, unsigned long nfolios);
 
-static inline bool is_cow_mapping(vm_flags_t flags)
+/**
+ * vma_flags_is_cow_mapping() - Do these VMA flags imply a CoW mapping?
+ * @flags: The VMA flags to check.
+ *
+ * Mappings which could be CoW'd (subject to Copy-On-Write faults) are
+ * described as CoW mappings.
+ *
+ * All mappings backed by anonymous folios (all anonymous mappings and most
+ * MAP_PRIVATE-file backed ranges) are CoW mappings.
+ *
+ * All other mappings (including all writable MAP_SHARED mappings) are
+ * non-CoW.
+ *
+ * The criteria are !VMA_SHARED_BIT, VMA_MAYWRITE_BIT.
+ *
+ * VMA_MAYWRITE_BIT is checked instead of VMA_WRITE_BIT to account for both
+ * future mprotect() calls which can render a read-only mapping writable, and
+ * GUP with FOLL_FORCE (e.g. ptrace) which can CoW a read-only mapping.
+ *
+ * - No anonymous mapping can ever clear VMA_MAYWRITE_BIT.
+ *
+ * - Writes to anonymous mappings do not immediately result in CoW faults but
+ *   may do so after the process is forked or if a read is followed by a
+ *   write.
+ *
+ * - Writes to MAP_PRIVATE file-backed mappings result in CoW faults and may
+ *   do so again after fork.
+ *
+ * - MAP_SHARED mappings of a file opened read-only are transformed into
+ *   VMA_MAYSHARE_BIT, !VMA_SHARED_BIT, !VMA_MAYWRITE_BIT mappings, so remain
+ *   non-CoW.
+ *
+ * - Drivers may clear VMA_MAYWRITE_BIT but do so at mmap() time and cannot
+ *   mark themselves anonymous. Having cleared this flag it is not valid for
+ *   them to leave the VMA_WRITE_BIT flag set.
+ *
+ * As a consequence, the anonymous reverse mapping only tracks CoW mappings.
+ *
+ * Returns: true if the flags indicate a CoW mapping, otherwise false.
+ */
+static inline bool vma_flags_is_cow_mapping(const vma_flags_t *flags)
 {
-	return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
+	return vma_flags_test(flags, VMA_MAYWRITE_BIT) &&
+		!vma_flags_test(flags, VMA_SHARED_BIT);
 }
 
-static inline bool vma_desc_is_cow_mapping(struct vm_area_desc *desc)
+/**
+ * vma_is_cow_mapping() - Is this VMA a CoW mapping?
+ * @vma: The VMA to check.
+ *
+ * See vma_flags_is_cow_mapping() for details.
+ *
+ * Returns: true if the VMA is a CoW mapping, otherwise false.
+ */
+static inline bool vma_is_cow_mapping(const struct vm_area_struct *vma)
 {
-	const vma_flags_t *flags = &desc->vma_flags;
+	return vma_flags_is_cow_mapping(&vma->flags);
+}
 
-	return vma_flags_test(flags, VMA_MAYWRITE_BIT) &&
-		!vma_flags_test(flags, VMA_SHARED_BIT);
+/**
+ * vma_desc_is_cow_mapping() - Is this VMA descriptor a CoW mapping?
+ * @desc: The VMA descriptor to check.
+ *
+ * See vma_flags_is_cow_mapping() for details.
+ *
+ * Returns: true if the VMA descriptor describes a CoW mapping, otherwise
+ * false.
+ */
+static inline bool vma_desc_is_cow_mapping(struct vm_area_desc *desc)
+{
+	return vma_flags_is_cow_mapping(&desc->vma_flags);
 }
 
 #ifndef CONFIG_MMU
--- a/kernel/events/uprobes.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/kernel/events/uprobes.c
@@ -513,7 +513,7 @@ int uprobe_write(struct arch_uprobe *aup
 
 	uprobe = container_of(auprobe, struct uprobe, arch);
 
-	if (WARN_ON_ONCE(!is_cow_mapping(vma->vm_flags)))
+	if (WARN_ON_ONCE(!vma_is_cow_mapping(vma)))
 		return -EINVAL;
 
 	/*
--- a/mm/gup.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/mm/gup.c
@@ -1236,7 +1236,7 @@ static int check_vma_flags(struct vm_are
 			 * Anon pages in shared mappings are surprising: now
 			 * just reject it.
 			 */
-			if (!is_cow_mapping(vm_flags))
+			if (!vma_is_cow_mapping(vma))
 				return -EFAULT;
 		}
 	} else if (!(vm_flags & VM_READ)) {
--- a/mm/huge_memory.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/mm/huge_memory.c
@@ -1681,7 +1681,7 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_
 	BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
 	BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
 						(VM_PFNMAP|VM_MIXEDMAP));
-	BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
+	BUG_ON((vma->vm_flags & VM_PFNMAP) && vma_is_cow_mapping(vma));
 
 	pfnmap_setup_cachemode_pfn(pfn, &pgprot);
 
@@ -1789,7 +1789,7 @@ vm_fault_t vmf_insert_pfn_pud(struct vm_
 	BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
 	BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
 						(VM_PFNMAP|VM_MIXEDMAP));
-	BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
+	BUG_ON((vma->vm_flags & VM_PFNMAP) && vma_is_cow_mapping(vma));
 
 	pfnmap_setup_cachemode_pfn(pfn, &pgprot);
 
@@ -1931,7 +1931,7 @@ int copy_huge_pmd(struct mm_struct *dst_
 		 * applied special bit, or we made the PRIVATE mapping be
 		 * able to wrongly write to the backend MMIO.
 		 */
-		VM_WARN_ON_ONCE(is_cow_mapping(src_vma->vm_flags) && pmd_write(pmd));
+		VM_WARN_ON_ONCE(vma_is_cow_mapping(src_vma) && pmd_write(pmd));
 		goto set_pmd;
 	}
 
@@ -2052,7 +2052,7 @@ int copy_huge_pud(struct mm_struct *dst_
 	 * TODO: once we support anonymous pages, use
 	 * folio_try_dup_anon_rmap_*() and split if duplicating fails.
 	 */
-	if (is_cow_mapping(vma->vm_flags) && pud_write(pud)) {
+	if (vma_is_cow_mapping(vma) && pud_write(pud)) {
 		pudp_set_wrprotect(src_mm, addr, src_pud);
 		pud = pud_wrprotect(pud);
 	}
--- a/mm/hugetlb.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/mm/hugetlb.c
@@ -4898,7 +4898,7 @@ int copy_hugetlb_page_range(struct mm_st
 	pte_t *src_pte, *dst_pte, entry;
 	struct folio *pte_folio;
 	unsigned long addr;
-	bool cow = is_cow_mapping(src_vma->vm_flags);
+	bool cow = vma_is_cow_mapping(src_vma);
 	struct hstate *h = hstate_vma(src_vma);
 	unsigned long sz = huge_page_size(h);
 	unsigned long npages = pages_per_huge_page(h);
--- a/mm/internal.h~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/mm/internal.h
@@ -1353,7 +1353,7 @@ static inline bool gup_must_unshare(stru
 		 * ... because we only care about writable private ("COW")
 		 * mappings where we have to break COW early.
 		 */
-		return is_cow_mapping(vma->vm_flags);
+		return vma_is_cow_mapping(vma);
 	}
 
 	/* Paired with a memory barrier in folio_try_share_anon_rmap_*(). */
--- a/mm/memory.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/mm/memory.c
@@ -780,7 +780,7 @@ static inline struct page *__vm_normal_p
 				/* Only CoW'ed anon folios are "normal". */
 				if (pfn == index)
 					return NULL;
-				if (!is_cow_mapping(vma->vm_flags))
+				if (!vma_is_cow_mapping(vma))
 					return NULL;
 			}
 		}
@@ -1002,7 +1002,6 @@ copy_nonpresent_pte(struct mm_struct *ds
 		pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *dst_vma,
 		struct vm_area_struct *src_vma, unsigned long addr, int *rss)
 {
-	vm_flags_t vm_flags = dst_vma->vm_flags;
 	pte_t orig_pte = ptep_get(src_pte);
 	softleaf_t entry = softleaf_from_pte(orig_pte);
 	pte_t pte = orig_pte;
@@ -1026,7 +1025,7 @@ copy_nonpresent_pte(struct mm_struct *ds
 		rss[mm_counter(folio)]++;
 
 		if (!softleaf_is_migration_read(entry) &&
-				is_cow_mapping(vm_flags)) {
+				vma_is_cow_mapping(dst_vma)) {
 			/*
 			 * COW mappings require pages in both parent and child
 			 * to be set to read. A previously exclusive entry is
@@ -1067,7 +1066,7 @@ copy_nonpresent_pte(struct mm_struct *ds
 		 * save and restore device driver state).
 		 */
 		if (softleaf_is_device_private_write(entry) &&
-		    is_cow_mapping(vm_flags)) {
+		    vma_is_cow_mapping(dst_vma)) {
 			entry = make_readable_device_private_entry(
 							swp_offset(entry));
 			pte = swp_entry_to_pte(entry);
@@ -1082,7 +1081,7 @@ copy_nonpresent_pte(struct mm_struct *ds
 		 * exclusive entries currently only support private writable
 		 * (ie. COW) mappings.
 		 */
-		VM_BUG_ON(!is_cow_mapping(src_vma->vm_flags));
+		VM_BUG_ON(!vma_is_cow_mapping(src_vma));
 		if (try_restore_exclusive_pte(src_vma, addr, src_pte, orig_pte))
 			return -EBUSY;
 		return -ENOENT;
@@ -1181,7 +1180,7 @@ static __always_inline void __copy_prese
 	}
 
 	/* If it's a COW mapping, write protect it both processes. */
-	if (is_cow_mapping(src_vma->vm_flags) && writable) {
+	if (vma_is_cow_mapping(src_vma) && writable) {
 		wrprotect_ptes(src_mm, addr, src_pte, nr);
 		pte = pte_wrprotect(pte);
 	}
@@ -1602,9 +1601,9 @@ copy_page_range(struct vm_area_struct *d
 	 * We need to invalidate the secondary MMU mappings only when
 	 * there could be a permission downgrade on the ptes of the
 	 * parent mm. And a permission downgrade will only happen if
-	 * is_cow_mapping() returns true.
+	 * vma_is_cow_mapping() returns true.
 	 */
-	is_cow = is_cow_mapping(src_vma->vm_flags);
+	is_cow = vma_is_cow_mapping(src_vma);
 
 	if (is_cow) {
 		mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE,
@@ -2437,7 +2436,7 @@ static bool vm_mixed_zeropage_allowed(st
 	if (mm_forbids_zeropage(vma->vm_mm))
 		return false;
 	/* zeropages in COW mappings are common and unproblematic. */
-	if (is_cow_mapping(vma->vm_flags))
+	if (vma_is_cow_mapping(vma))
 		return true;
 	/* Mappings that do not allow for writable PTEs are unproblematic. */
 	if (!(vma->vm_flags & (VM_WRITE | VM_MAYWRITE)))
@@ -2888,7 +2887,7 @@ vm_fault_t vmf_insert_pfn_prot(struct vm
 	BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
 	BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
 						(VM_PFNMAP|VM_MIXEDMAP));
-	BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
+	BUG_ON((vma->vm_flags & VM_PFNMAP) && vma_is_cow_mapping(vma));
 	BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
 
 	if (addr < vma->vm_start || addr >= vma->vm_end)
@@ -3300,7 +3299,7 @@ static int remap_pfn_range_prepare_vma(s
 				       unsigned long size)
 {
 	const unsigned long end = addr + PAGE_ALIGN(size);
-	const bool is_cow = is_cow_mapping(vma->vm_flags);
+	const bool is_cow = vma_is_cow_mapping(vma);
 	int err;
 
 	err = get_remap_pgoff(is_cow, addr, end, vma->vm_start, vma->vm_end,
@@ -6800,7 +6799,7 @@ static vm_fault_t sanitize_fault_flags(s
 		 * FAULT_FLAG_UNSHARE only applies to COW mappings. Let's
 		 * just treat it like an ordinary read-fault otherwise.
 		 */
-		if (!is_cow_mapping(vma->vm_flags))
+		if (!vma_is_cow_mapping(vma))
 			*flags &= ~FAULT_FLAG_UNSHARE;
 	} else if (*flags & FAULT_FLAG_WRITE) {
 		/* Write faults on read-only mappings are impossible ... */
@@ -6808,7 +6807,7 @@ static vm_fault_t sanitize_fault_flags(s
 			return VM_FAULT_SIGSEGV;
 		/* ... and FOLL_FORCE only applies to COW mappings. */
 		if (WARN_ON_ONCE(!(vma->vm_flags & VM_WRITE) &&
-				 !is_cow_mapping(vma->vm_flags)))
+				 !vma_is_cow_mapping(vma)))
 			return VM_FAULT_SIGSEGV;
 	}
 #ifdef CONFIG_PER_VMA_LOCK
--- a/mm/mempolicy.c~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/mm/mempolicy.c
@@ -844,7 +844,7 @@ bool folio_can_map_prot_numa(struct foli
 		return false;
 
 	/* Also skip shared copy-on-write folios */
-	if (is_cow_mapping(vma->vm_flags) && folio_maybe_mapped_shared(folio))
+	if (vma_is_cow_mapping(vma) && folio_maybe_mapped_shared(folio))
 		return false;
 
 	/* Folios are pinned and can't be migrated */
--- a/tools/testing/vma/include/dup.h~mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping
+++ a/tools/testing/vma/include/dup.h
@@ -1162,6 +1162,17 @@ static inline bool vma_is_shared_maywrit
 	return is_shared_maywrite(&vma->flags);
 }
 
+static inline bool vma_flags_is_cow_mapping(const vma_flags_t *flags)
+{
+	return vma_flags_test(flags, VMA_MAYWRITE_BIT) &&
+		!vma_flags_test(flags, VMA_SHARED_BIT);
+}
+
+static inline bool vma_is_cow_mapping(const struct vm_area_struct *vma)
+{
+	return vma_flags_is_cow_mapping(&vma->flags);
+}
+
 static inline struct vm_area_struct *vma_next(struct vma_iterator *vmi)
 {
 	/*
_

Patches currently in -mm which might be from ljs@kernel.org are

mm-introduce-linear_anon_page_index.patch
mm-abstract-vma_address-and-introduce-vma_anon_address.patch
mm-update-print_bad_page_map-to-show-anon-index-if-appropriate.patch
mm-introduce-and-use-vma_filebacked_address.patch
mm-vma-fix-self-merge-check-in-copy_vma.patch
tools-testing-vma-add-tests-for-copy_vma-self-merge.patch
mm-propagate-vma-anonymous-page-offset-on-map-remap-split-merge.patch
mm-rmap-track-whether-the-page-vma-mapped-pgoff-is-anonymous.patch
mm-clean-up-vma_address_end.patch
mm-huge_memory-update-remove_migration_pmd-to-accept-a-folio.patch
mm-migrate-calculate-large-folio-page-index-using-pfn.patch
mm-rmap-use-anon-pgoff-to-track-map_private-file-backed-anon-folios.patch
tools-testing-vma-expand-vma-merge-tests-to-assert-anon-pgoff.patch
tools-testing-selftests-mm-test-anonymous-page-offset-merge-behaviour.patch
mm-vma-only-permit-map_private-dev-zero-to-be-mapped-anonymous.patch
mm-vma-make-map_private-mapped-dev-zero-mappings-truly-anonymous.patch
tools-testing-vma-add-test-to-assert-map_private-dev-zero-is-anon.patch
tools-testing-selftests-mm-add-map_private-dev-zero-merge-tests.patch
mm-add-some-missing-includes-to-mm-local-headers.patch
maintainers-add-drivers-char-memc-to-mm-misc-memory-mapping-sections.patch