Re: [PATCH 01/30] mm: move vma_start_pgoff() into mm.h and clean up

On Tue, Jun 30, 2026 at 05:10:55PM +0100, Pedro Falcato wrote:

On Mon, Jun 29, 2026 at 01:23:12PM +0100, Lorenzo Stoakes wrote:

quoted

vma_last_pgoff() already lives there, so it's a bit odd to keep
vma_start_pgoff() in mm/interval_tree.c. Move them together.

Hmm, a part of me wonders if this is the part where we should start cleaning
up mm.h into vma.h or something. Probably not, it would be extra churn right
now.

Yeah the issue is there's some confusion about vma.h - mm.h should be for
stuff that is used outside of mm, and these helpers are definitely like
that.

vma.h is purely for internal mm vma stuff, and most people should be accessing
that via internal.h (I address that in patch 27).

I do wonder if that could be done more nicely but punt that to another time.

But also probably worth doing a pass over some of the defines, I have a
bunch of series chur^W changing stuff lately so can do a follow up on that
maybe.

quoted

These each return unsigned long, which pgoff_t is typedef'd to. Make this
consistent and have these functions return pgoff_t instead.

Additionally, express vma_last_pgoff() in terms of vma_start_pgoff(), since
we wrap the vma->vm_pgoff access, we may as well use it here.

Also while we're here, const-ify the VMA and cleanup a bit.

No functional change intended.

Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>

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

Thanks!

quoted

---
 include/linux/mm.h | 9 +++++++--
 mm/interval_tree.c | 5 -----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 485df9c2dbdd..059144435729 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h

@@ -4278,9 +4278,14 @@ static inline unsigned long vma_pages(const struct vm_area_struct *vma)
 	return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 }

-static inline unsigned long vma_last_pgoff(struct vm_area_struct *vma)
+static inline pgoff_t vma_start_pgoff(const struct vm_area_struct *vma)
 {
-	return vma->vm_pgoff + vma_pages(vma) - 1;
+	return vma->vm_pgoff;
+}
+
+static inline pgoff_t vma_last_pgoff(const struct vm_area_struct *vma)
+{
+	return vma_start_pgoff(vma) + vma_pages(vma) - 1;
 }

 static inline unsigned long vma_desc_size(const struct vm_area_desc *desc)

diff --git a/mm/interval_tree.c b/mm/interval_tree.c
index 32bcfbfcf15f..344d1f5946c7 100644
--- a/mm/interval_tree.c
+++ b/mm/interval_tree.c

@@ -10,11 +10,6 @@
 #include <linux/rmap.h>
 #include <linux/interval_tree_generic.h>

-static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
-{
-	return v->vm_pgoff;
-}
-
 INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.rb,
 		     unsigned long, shared.rb_subtree_last,
 		     vma_start_pgoff, vma_last_pgoff, /* empty */, vma_interval_tree)
--

2.54.0

--
Pedro

Cheers, Lorenzo