+ mm-huge_memory-fix-folio-isnt-locked-in-softleaf_to_folio-v4.patch added to mm-hotfixes-unstable branch

+ mm-huge_memory-fix-folio-isnt-locked-in-softleaf_to_folio-v4.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm-huge_memory-fix-folio-isnt-locked-in-softleaf_to_folio-v4
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-huge_memory-fix-folio-isnt-locked-in-softleaf_to_folio-v4.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-huge_memory-fix-folio-isnt-locked-in-softleaf_to_folio-v4.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Jinjiang Tu <tujinjiang@huawei.com>
Subject: mm-huge_memory-fix-folio-isnt-locked-in-softleaf_to_folio-v4
Date: Sat, 21 Mar 2026 15:52:14 +0800

update function name and comments

Link: https://lkml.kernel.org/r/20260321075214.3305564-1-tujinjiang@huawei.com
Fixes: e9b61f19858a ("thp: reintroduce split_huge_page()")
Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: <stable@vger.kernel.org>
Cc: Barry Song <baohua@kernel.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/leafops.h |   14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

--- a/include/linux/leafops.h~mm-huge_memory-fix-folio-isnt-locked-in-softleaf_to_folio-v4
+++ a/include/linux/leafops.h
@@ -363,10 +363,14 @@ static inline unsigned long softleaf_to_
 	return swp_offset(entry) & SWP_PFN_MASK;
 }
 
-static inline void softleaf_migration_entry_check(softleaf_t entry,
-			struct folio *folio)
+static inline void softleaf_migration_sync(softleaf_t entry,
+		struct folio *folio)
 {
-	/* See __split_folio_to_order() comment */
+	/*
+	 * Ensure we do not race with split, which might alter tail pages into new
+	 * folios and thus result in observing an unlocked folio.
+	 * This matches the write barrier in __split_folio_to_order().
+	 */
 	smp_rmb();
 
 	/*
@@ -388,7 +392,7 @@ static inline struct page *softleaf_to_p
 
 	VM_WARN_ON_ONCE(!softleaf_has_pfn(entry));
 	if (softleaf_is_migration(entry))
-		softleaf_migration_entry_check(entry, page_folio(page));
+		softleaf_migration_sync(entry, page_folio(page));
 
 	return page;
 }
@@ -405,7 +409,7 @@ static inline struct folio *softleaf_to_
 
 	VM_WARN_ON_ONCE(!softleaf_has_pfn(entry));
 	if (softleaf_is_migration(entry))
-		softleaf_migration_entry_check(entry, folio);
+		softleaf_migration_sync(entry, folio);
 
 	return folio;
 }
_

Patches currently in -mm which might be from tujinjiang@huawei.com are

mm-huge_memory-fix-folio-isnt-locked-in-softleaf_to_folio.patch
mm-huge_memory-fix-folio-isnt-locked-in-softleaf_to_folio-v4.patch
mm-hugetlb-fix-memory-offline-failure-due-to-hwpoisoned-file-hugetlb.patch