+ mm-abstract-vma_address-and-introduce-vma_anon_address.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

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The patch titled
     Subject: mm: abstract vma_address() and introduce vma_anon_address()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-abstract-vma_address-and-introduce-vma_anon_address.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-abstract-vma_address-and-introduce-vma_anon_address.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Subject: mm: abstract vma_address() and introduce vma_anon_address()
Date: Thu, 13 Aug 2026 18:32:21 +0100

Introduce __vma_address() which abstracts the VMA start page offset field
as pgoff_start, then update vma_address() to use it.

Then introduce vma_anon_address() which does the equivalent of
vma_address(), only using the anonymous page offset of the VMA rather than
the file-backed one.

Also add an assert to ensure that the function is not called for mappings
which are file-backed but not MAP_PRIVATE to ensure it is only used in the
correct places.

This will be necessary for determining the address of a folio's index
within a VMA when the folio belongs to a MAP_PRIVATE file-backed VMA but
has been CoW'd, and thus is anonymous, once the anonymous VMA page offset
field is used for the reverse mapping.

No callers are updated, so no functional change intended.

Link: https://lore.kernel.org/20260813-b4-scalable-cow-virt-pgoff-v5-4-c21581c0c3c8@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: 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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/internal.h |   49 ++++++++++++++++++++++++++++++++++++------------
 1 file changed, 37 insertions(+), 12 deletions(-)

--- a/mm/internal.h~mm-abstract-vma_address-and-introduce-vma_anon_address
+++ a/mm/internal.h
@@ -1017,19 +1017,9 @@ void mlock_drain_remote(int cpu);
 
 extern pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma);
 
-/**
- * vma_address - Find the virtual address a page range is mapped at
- * @vma: The vma which maps this object.
- * @pgoff: The page offset within its object.
- * @nr_pages: The number of pages to consider.
- *
- * If any page in this range is mapped by this VMA, return the first address
- * where any of these pages appear.  Otherwise, return -EFAULT.
- */
-static inline unsigned long vma_address(const struct vm_area_struct *vma,
-		pgoff_t pgoff, unsigned long nr_pages)
+static inline unsigned long __vma_address(const struct vm_area_struct *vma,
+		pgoff_t pgoff, pgoff_t pgoff_start, unsigned long nr_pages)
 {
-	const pgoff_t pgoff_start = vma_start_pgoff(vma);
 	unsigned long address;
 
 	if (pgoff >= pgoff_start) {
@@ -1047,6 +1037,41 @@ static inline unsigned long vma_address(
 	return address;
 }
 
+/**
+ * vma_address - Find the virtual address a page range is mapped at.
+ * @vma: The vma which maps this object.
+ * @pgoff: The page offset within its object.
+ * @nr_pages: The number of pages to consider.
+ *
+ * If any page in this range is mapped by this VMA, return the first address
+ * where any of these pages appear.  Otherwise, return -EFAULT.
+ */
+static inline unsigned long vma_address(const struct vm_area_struct *vma,
+		pgoff_t pgoff, unsigned long nr_pages)
+{
+	return __vma_address(vma, pgoff, vma_start_pgoff(vma), nr_pages);
+}
+
+/**
+ * vma_anon_address - Find the address an anonymous folio with index @pgoff_anon
+ * is mapped at.
+ * @vma: The vma which maps this object.
+ * @pgoff_anon: The anonymous page index belonging to the folio.
+ * @nr_pages: The number of pages to consider.
+ *
+ * This is only valid for anonymous or MAP_PRIVATE-mapped file-backed VMAs.
+ *
+ * Returns: If any page in this range is mapped by this VMA, return the first
+ * address where any of these pages appear. Otherwise, return -EFAULT.
+ */
+static inline unsigned long vma_anon_address(const struct vm_area_struct *vma,
+		pgoff_t pgoff_anon, unsigned long nr_pages)
+{
+	VM_WARN_ON_ONCE(!vma_is_cow_mapping(vma));
+
+	return __vma_address(vma, pgoff_anon, vma_start_anon_pgoff(vma), nr_pages);
+}
+
 /*
  * Then at what user virtual address will none of the range be found in vma?
  * Assumes that vma_address() already returned a good starting address.
_

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

mm-vma-introduce-vma-anon-page-offset-field-and-add-helpers.patch
mm-provide-vma_is_cow_mapping-and-remove-is_cow_mapping.patch
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-add-some-missing-includes-to-mm-local-headers.patch
maintainers-add-drivers-char-memc-to-mm-misc-memory-mapping-sections.patch