[PATCH 5.15 173/206] mm/pagewalk: add walk_page_range_vma()

Greg Kroah-Hartman
2026-02-04T15:03:00Z

From: David Hildenbrand <david@redhat.com>

[ Upstream commit e07cda5f232fac4de0925d8a4c92e51e41fa2f6e ]

Let's add walk_page_range_vma(), which is similar to walk_page_vma(),
however, is only interested in a subset of the VMA range.

To be used in KSM code to stop using follow_page() next.

Link: https://lkml.kernel.org/r/20221021101141.84170-8-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: f5548c318d6 ("ksm: use range-walk function to jump over holes in scan_get_next_rmap_item")
Signed-off-by: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/pagewalk.h | 3 +++
mm/pagewalk.c | 20 ++++++++++++++++++++
2 files changed, 23 insertions(+)

--- a/include/linux/pagewalk.h
+++ b/include/linux/pagewalk.h
@@ -99,6 +99,9 @@ int walk_page_range_novma(struct mm_stru
unsigned long end, const struct mm_walk_ops *ops,
pgd_t *pgd,
void *private);
+int walk_page_range_vma(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end, const struct mm_walk_ops *ops,
+ void *private);
int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
void *private);
int walk_page_mapping(struct address_space *mapping, pgoff_t first_index,
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -509,6 +509,26 @@ int walk_page_range_novma(struct mm_stru
return walk_pgd_range(start, end, &walk);
}

+int walk_page_range_vma(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end, const struct mm_walk_ops *ops,
+ void *private)
+{
+ struct mm_walk walk = {
+ .ops = ops,
+ .mm = vma->vm_mm,
+ .vma = vma,
+ .private = private,
+ };
+
+ if (start >= end || !walk.mm)
+ return -EINVAL;
+ if (start < vma->vm_start || end > vma->vm_end)
+ return -EINVAL;
+
+ mmap_assert_locked(walk.mm);
+ return __walk_page_range(start, end, &walk);
+}
+
int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
void *private)
{