[RFC Patch 04/11] mm/memory-failure: convert try_to_split_thp_page() to use split_folio_to_order()

[Wei Yang <richard.weiyang@gmail.com>]

The function try_to_split_thp_page() currently uses the page-style
split_huge_page_to_order() API to split a huge page.

Since the returned page is immediately unlocked after the split
completes, the specific locking behavior of split_huge_page_to_order()
(returning the page locked) is irrelevant here.

This allows us to replace the call with the folio-style equivalent,
split_folio_to_order(). This conversion improves code consistency
by adopting the modern folio API throughout the THP splitting
logic.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
---
 include/linux/huge_mm.h | 6 ++++++
 mm/memory-failure.c     | 7 ++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 3e01184cf274..872b4ed2a477 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -647,6 +647,12 @@ static inline int split_folio_to_list(struct folio *folio, struct list_head *lis
 	return -EINVAL;
 }
 
+static inline int split_folio_to_order(struct folio *folio, int new_order)
+{
+	VM_WARN_ON_ONCE_FOLIO(1, folio);
+	return -EINVAL;
+}
+
 static inline int try_folio_split_to_order(struct folio *folio,
 		struct page *page, unsigned int new_order)
 {
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index fbc5a01260c8..600666491f52 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1665,11 +1665,12 @@ static int identify_page_state(unsigned long pfn, struct page *p,
 static int try_to_split_thp_page(struct page *page, unsigned int new_order,
 		bool release)
 {
+	struct folio *folio = page_folio(page);
 	int ret;
 
-	lock_page(page);
-	ret = split_huge_page_to_order(page, new_order);
-	unlock_page(page);
+	folio_lock(folio);
+	ret = split_folio_to_order(folio, new_order);
+	folio_unlock(folio);
 
 	if (ret && release)
 		put_page(page);
-- 
2.34.1