+ mm-vma-move-__install_special_mapping-to-vmac.patch added to mm-new branch

+ mm-vma-move-__install_special_mapping-to-vmac.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm/vma: move __install_special_mapping() to vma.c
has been added to the -mm mm-new branch.  Its filename is
     mm-vma-move-__install_special_mapping-to-vmac.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vma-move-__install_special_mapping-to-vmac.patch

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

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days

------------------------------------------------------
From: Lorenzo Stoakes <ljs@kernel.org>
Subject: mm/vma: move __install_special_mapping() to vma.c
Date: Fri, 10 Jul 2026 21:17:05 +0100

This function is operating on VMAs and rightly belongs in vma.c, where it
can be subject to VMA userland testing and allows us to isolate it from the
rest of mm.

The _install_special_mapping() function will remain in mmap.c as a wrapper,
since this is used by architecture-specific code.

Doing so allows us to isolate more functions in vma.c for the same reasons.

This forms part of work to allow for tracking MAP_PRIVATE file-backed
mappings by their anonymous virtual page offset, as doing so allows us to
isolate and keep code that interacts with this together.

No functional change intended.

Link: https://lore.kernel.org/20260710-b4-pre-scalable-cow-v2-24-2a5aa403d977@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Gregory Price <gourry@gourry.net>
Cc: Ackerley Tng <ackerleytng@google.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Kai Huang <kai.huang@intel.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: SJ Park <sj@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mmap.c |   38 --------------------------------------
 mm/vma.c  |   38 ++++++++++++++++++++++++++++++++++++++
 mm/vma.h  |    5 +++++
 3 files changed, 43 insertions(+), 38 deletions(-)

--- a/mm/mmap.c~mm-vma-move-__install_special_mapping-to-vmac
+++ a/mm/mmap.c
@@ -1447,44 +1447,6 @@ static vm_fault_t special_mapping_fault(
 	return VM_FAULT_SIGBUS;
 }
 
-static struct vm_area_struct *__install_special_mapping(
-	struct mm_struct *mm,
-	unsigned long addr, unsigned long len,
-	vm_flags_t vm_flags, void *priv,
-	const struct vm_operations_struct *ops)
-{
-	int ret;
-	struct vm_area_struct *vma;
-
-	vma = vm_area_alloc(mm);
-	if (unlikely(vma == NULL))
-		return ERR_PTR(-ENOMEM);
-
-	vma_set_range(vma, addr, addr + len, 0);
-	vm_flags |= mm->def_flags | VM_DONTEXPAND;
-	if (pgtable_supports_soft_dirty())
-		vm_flags |= VM_SOFTDIRTY;
-	vm_flags_init(vma, vm_flags & ~VM_LOCKED_MASK);
-	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
-
-	vma->vm_ops = ops;
-	vma->vm_private_data = priv;
-
-	ret = insert_vm_struct(mm, vma);
-	if (ret)
-		goto out;
-
-	vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT);
-
-	perf_event_mmap(vma);
-
-	return vma;
-
-out:
-	vm_area_free(vma);
-	return ERR_PTR(ret);
-}
-
 bool vma_is_special_mapping(const struct vm_area_struct *vma,
 	const struct vm_special_mapping *sm)
 {
--- a/mm/vma.c~mm-vma-move-__install_special_mapping-to-vmac
+++ a/mm/vma.c
@@ -3399,3 +3399,41 @@ __weak unsigned long vma_mmu_pagesize(st
 {
 	return vma_kernel_pagesize(vma);
 }
+
+struct vm_area_struct *__install_special_mapping(
+	struct mm_struct *mm,
+	unsigned long addr, unsigned long len,
+	vm_flags_t vm_flags, void *priv,
+	const struct vm_operations_struct *ops)
+{
+	int ret;
+	struct vm_area_struct *vma;
+
+	vma = vm_area_alloc(mm);
+	if (unlikely(vma == NULL))
+		return ERR_PTR(-ENOMEM);
+
+	vma_set_range(vma, addr, addr + len, 0);
+	vm_flags |= mm->def_flags | VM_DONTEXPAND;
+	if (pgtable_supports_soft_dirty())
+		vm_flags |= VM_SOFTDIRTY;
+	vm_flags_init(vma, vm_flags & ~VM_LOCKED_MASK);
+	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+
+	vma->vm_ops = ops;
+	vma->vm_private_data = priv;
+
+	ret = insert_vm_struct(mm, vma);
+	if (ret)
+		goto out;
+
+	vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT);
+
+	perf_event_mmap(vma);
+
+	return vma;
+
+out:
+	vm_area_free(vma);
+	return ERR_PTR(ret);
+}
--- a/mm/vma.h~mm-vma-move-__install_special_mapping-to-vmac
+++ a/mm/vma.h
@@ -775,4 +775,9 @@ static inline bool map_deny_write_exec(c
 }
 #endif
 
+struct vm_area_struct *__install_special_mapping(struct mm_struct *mm,
+		unsigned long addr, unsigned long len,
+		vm_flags_t vm_flags, void *priv,
+		const struct vm_operations_struct *ops);
+
 #endif	/* __MM_VMA_H */
_

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

mm-move-alloc-tag-to-mm.patch
mm-ptdump-always-stabilise-against-page-table-freeing-using-init_mm.patch
mm-vmalloc-acquire-init_mm-read-lock-on-huge-vmap-promotion.patch
revert-arm64-enable-vmalloc-huge-with-ptdump.patch
mm-move-vma_start_pgoff-into-mmh-and-clean-up.patch
mm-add-kdoc-comments-for-vma_start-last_pgoff.patch
tools-testing-vma-use-vma_start_pgoff-in-merge-tests.patch
mm-introduce-and-use-vma_end_pgoff.patch
mm-rmap-update-mm-interval_treec-comments.patch
mm-rmap-parameterise-vma_interval_tree_-by-address_space.patch
mm-rmap-elide-unnecessary-static-inlines-in-interval_treec.patch
mm-rmap-rename-vma_interval_tree_-to-mapping_rmap_tree_.patch
mm-rmap-parameterise-anon_vma_interval_tree_-by-anon_vma.patch
mm-rmap-rename-anon_vma_interval_tree_-params-and-use-pgoff_t.patch
mm-rmap-rename-anon_vma_interval_tree_-to-anon_rmap_tree_.patch
maintainers-move-mm-interval_treec-to-rmap-section.patch
mm-vma-introduce-and-use-vmg_pages-vmg__pgoff.patch
mm-vma-clean-up-anon_vma_compatible.patch
mm-vma-refactor-vmg_adjust_set_range-for-clarity.patch
mm-vma-minor-cleanup-of-expand_.patch
mm-introduce-and-use-linear_page_delta.patch
mm-vma-use-vma_start_pgoff-linear_page_index-in-mm-code.patch
mm-prefer-vma__pgoff-to-vma-vm_pgoff-in-kernel.patch
mm-vma-remove-duplicative-vma_pgoff_offset-helper.patch
mm-use-linear_page_-consistently.patch
mm-vma-introduce-vma_assert_can_modify.patch
mm-vma-add-and-use-vma__pgoff.patch
mm-vma-move-__install_special_mapping-to-vmac.patch
mm-vma-make-vma_set_range-static-drop-insert_vm_struct-decl.patch
mm-vma-update-vma_shrink-to-not-pass-start-pgoff-parameters.patch
mm-vma-update-vmg_adjust_set_range-to-offset-pgoff-instead.patch
mm-vma-slightly-rework-the-anonymous-check-in-__mmap_new_vma.patch
mm-vma-introduce-and-use-vma_set_pgoff.patch
mm-vma-correct-incorrect-vmah-inclusion.patch
mm-vma-use-guard-clauses-in-can_vma_merge_.patch
tools-testing-vma-default-vma-mm-flag-bits-to-64-bit.patch
tools-testing-vma-output-compared-expression-on-assert_.patch