[merged mm-stable] mm-mlock-avoid-folio_within_range-on-ksm-pages.patch removed from -mm tree

[merged mm-stable] mm-mlock-avoid-folio_within_range-on-ksm-pages.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: mlock: avoid folio_within_range() on KSM pages
has been removed from the -mm tree.  Its filename was
     mm-mlock-avoid-folio_within_range-on-ksm-pages.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Hugh Dickins <hughd@google.com>
Subject: mm: mlock: avoid folio_within_range() on KSM pages
Date: Mon, 23 Oct 2023 23:38:41 -0700 (PDT)

Since commit dc68badcede4 ("mm: mlock: update mlock_pte_range to handle
large folio") I've just occasionally seen VM_WARN_ON_FOLIO(folio_test_ksm)
warnings from folio_within_range(), in a splurge after testing with KSM
hyperactive.

folio_referenced_one()'s use of folio_within_vma() is safe because it
checks folio_test_large() first; but allow_mlock_munlock() needs to do the
same to avoid those warnings (or check !folio_test_ksm() itself?  Or move
either check into folio_within_range()?  Hard to tell without more
examples of its use).

Link: https://lkml.kernel.org/r/23852f6a-5bfa-1ffd-30db-30c5560ad426@google.com
Fixes: dc68badcede4 ("mm: mlock: update mlock_pte_range to handle large folio")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mlock.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/mm/mlock.c~mm-mlock-avoid-folio_within_range-on-ksm-pages
+++ a/mm/mlock.c
@@ -346,6 +346,10 @@ static inline bool allow_mlock_munlock(s
 	if (!(vma->vm_flags & VM_LOCKED))
 		return true;
 
+	/* folio_within_range() cannot take KSM, but any small folio is OK */
+	if (!folio_test_large(folio))
+		return true;
+
 	/* folio not in range [start, end), skip mlock */
 	if (!folio_within_range(folio, vma, start, end))
 		return false;
_

Patches currently in -mm which might be from hughd@google.com are