+ mm-gup-cleanup-pgtable-entry-accessors.patch added to mm-new branch

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

The patch titled
     Subject: mm/gup: cleanup pgtable entry accessors
has been added to the -mm mm-new branch.  Its filename is
     mm-gup-cleanup-pgtable-entry-accessors.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-gup-cleanup-pgtable-entry-accessors.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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------------------------------------------------------
From: Alexander Gordeev <agordeev@linux.ibm.com>
Subject: mm/gup: cleanup pgtable entry accessors
Date: Tue, 21 Apr 2026 07:17:54 +0200

PMD and PUD entries revalidation has the same semantics as PTE entry
revalidation.  Convert the remaining direct entry dereferences to the
corresponding accessors.

The PTE validation in gup_fast_pte_range() is inconsistent with the prior
value acquisition in the sense that it drops the lockless access
semantics.

Use the lockless accessor not only for the PTE, but also for the PMD
validation, which is likewise inconsistent with the prior value
acquisition in gup_fast_pmd_range().

Link: https://lore.kernel.org/20260421051754.1691221-1-agordeev@linux.ibm.com
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/gup.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/mm/gup.c~mm-gup-cleanup-pgtable-entry-accessors
+++ a/mm/gup.c
@@ -2865,8 +2865,8 @@ static int gup_fast_pte_range(pmd_t pmd,
 		if (!folio)
 			goto pte_unmap;
 
-		if (unlikely(pmd_val(pmd) != pmd_val(*pmdp)) ||
-		    unlikely(pte_val(pte) != pte_val(ptep_get(ptep)))) {
+		if (unlikely(pmd_val(pmd) != pmd_val(pmdp_get_lockless(pmdp))) ||
+		    unlikely(pte_val(pte) != pte_val(ptep_get_lockless(ptep)))) {
 			gup_put_folio(folio, 1, flags);
 			goto pte_unmap;
 		}
@@ -2942,7 +2942,7 @@ static int gup_fast_pmd_leaf(pmd_t orig,
 	if (!folio)
 		return 0;
 
-	if (unlikely(pmd_val(orig) != pmd_val(*pmdp))) {
+	if (unlikely(pmd_val(orig) != pmd_val(pmdp_get_lockless(pmdp)))) {
 		gup_put_folio(folio, refs, flags);
 		return 0;
 	}
@@ -2985,7 +2985,7 @@ static int gup_fast_pud_leaf(pud_t orig,
 	if (!folio)
 		return 0;
 
-	if (unlikely(pud_val(orig) != pud_val(*pudp))) {
+	if (unlikely(pud_val(orig) != pud_val(pudp_get(pudp)))) {
 		gup_put_folio(folio, refs, flags);
 		return 0;
 	}
_

Patches currently in -mm which might be from agordeev@linux.ibm.com are

mm-gup-cleanup-pgtable-entry-accessors.patch