+ mm-clean-up-is_guard_pte_marker.patch added to mm-new branch

+ mm-clean-up-is_guard_pte_marker.patch added to mm-new branch

[Andrew Morton]

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The patch titled
     Subject: mm: clean up is_guard_pte_marker()
has been added to the -mm mm-new branch.  Its filename is
     mm-clean-up-is_guard_pte_marker.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-clean-up-is_guard_pte_marker.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.

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------------------------------------------------------
From: Lance Yang <lance.yang@linux.dev>
Subject: mm: clean up is_guard_pte_marker()
Date: Wed, 24 Sep 2025 12:58:30 +0800

Let's simplify the implementation. The current code is redundant as it
effectively expands to:

  is_swap_pte(pte) &&
  is_pte_marker_entry(...) && // from is_pte_marker()
  is_pte_marker_entry(...)    // from is_guard_swp_entry()

While a modern compiler could likely optimize this away, let's have clean
code and not rely on it.

Link: https://lkml.kernel.org/r/20250924045830.3817-1-lance.yang@linux.dev
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Mika Penttilä <mpenttil@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/madvise.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/mm/madvise.c~mm-clean-up-is_guard_pte_marker
+++ a/mm/madvise.c
@@ -1071,8 +1071,8 @@ static bool is_valid_guard_vma(struct vm
 
 static bool is_guard_pte_marker(pte_t ptent)
 {
-	return is_pte_marker(ptent) &&
-		is_guard_swp_entry(pte_to_swp_entry(ptent));
+	return is_swap_pte(ptent) &&
+	       is_guard_swp_entry(pte_to_swp_entry(ptent));
 }
 
 static int guard_install_pud_entry(pud_t *pud, unsigned long addr,
_

Patches currently in -mm which might be from lance.yang@linux.dev are

hung_task-fix-warnings-caused-by-unaligned-lock-pointers.patch
mm-thp-fix-mte-tag-mismatch-when-replacing-zero-filled-subpages.patch
mm-clean-up-is_guard_pte_marker.patch