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

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

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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
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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