Re: [PATCH 16/30] mm/vma: use vma_start_pgoff(), linear_page_index() in mm code

On Thu, Jul 02, 2026 at 11:47:10AM +0100, Pedro Falcato wrote:

small nit: perhaps the subject should simply have mm: as it hits mm in general

On Mon, Jun 29, 2026 at 01:23:27PM +0100, Lorenzo Stoakes wrote:

quoted

There are many instances in which linear_page_index() (as well as
linear_page_delta()) is open-coded, which is confusing and inconsistent.

Additionally, vma->vm_pgoff doesn't necessarily make it clear that this is
the page offset of the start of the VMA range.

Doing so also aids greppability.

So use vma_start_pgoff() in favour of directly accessing vma->vm_pgoff, and
linear_page_index() where we can.

This also lays the ground for future changes which will add an anonymous
page offset in order to be able to index MAP_PRIVATE-file backed anon
folios in terms of their virtual page offset.

No functional change intended.

Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
---
 include/linux/huge_mm.h    |  1 +
 include/linux/hugetlb.h    |  3 +--
 include/linux/pagemap.h    |  2 +-
 mm/damon/vaddr.c           |  5 +++--
 mm/debug.c                 |  2 +-
 mm/filemap.c               |  7 ++++---
 mm/huge_memory.c           |  2 +-
 mm/hugetlb.c               | 11 ++++-------
 mm/internal.h              | 24 ++++++++++++++----------
 mm/khugepaged.c            |  3 ++-
 mm/madvise.c               |  6 +++---
 mm/mapping_dirty_helpers.c |  2 +-
 mm/memory.c                | 25 +++++++++++++------------
 mm/mempolicy.c             | 13 +++++++------
 mm/mremap.c                | 12 ++++--------
 mm/msync.c                 |  4 ++--
 mm/nommu.c                 |  7 ++++---
 mm/pagewalk.c              |  2 +-
 mm/shmem.c                 |  9 +++++----
 mm/userfaultfd.c           |  4 ++--
 mm/util.c                  |  4 ++--
 mm/vma.c                   | 15 +++++++--------
 mm/vma_exec.c              |  4 ++--
 mm/vma_init.c              |  2 +-
 24 files changed, 86 insertions(+), 83 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index ad20f7f8c179..653b81d08fe7 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h

@@ -230,6 +230,7 @@ static inline bool thp_vma_suitable_order(struct vm_area_struct *vma,

 	/* Don't have to check pgoff for anonymous vma */
 	if (!vma_is_anonymous(vma)) {
+		/* vma_start_pgoff() in mm.h so not available. */

Yay for gigaheaders...

Yup C headers are a constant pain :)

quoted

 		if (!IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
 				hpage_size >> PAGE_SHIFT))
 			return false;

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 2abaf99321e9..8390f50604d6 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h

@@ -792,8 +792,7 @@ static inline pgoff_t hugetlb_linear_page_index(struct vm_area_struct *vma,
 {
 	struct hstate *h = hstate_vma(vma);

-	return ((address - vma->vm_start) >> huge_page_shift(h)) +
-		(vma->vm_pgoff >> huge_page_order(h));
+	return linear_page_index(vma, address) >> huge_page_order(h);
 }

Anyway, nothing jumped out at me.

Reviewed-by: Pedro Falcato <pfalcato@suse.de>

Thanks!

--
Pedro

Cheers, Lorenzo