[PATCH] mm: migrate: use thp_order instead of HPAGE_PMD_ORDER for new page allocation.

[Zi Yan]

From: Zi Yan <ziy@xxxxxxxxxx>

With folios support, it is possible to have other than HPAGE_PMD_ORDER
THPs, in the form of folios, in the system. Use thp_order() to correctly
determine the source page order during migration.

Fixes: d68eccad3706 ("mm/filemap: Allow large folios to be added to the page cache")
Reported-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxxxx>
Link: https://lore.kernel.org/linux-mm/20220404132908.GA785673@u2004/
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
 mm/mempolicy.c | 2 +-
 mm/migrate.c   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 6b34c5d5e65a..88a74bc4cba5 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1209,7 +1209,7 @@ static struct page *new_page(struct page *page, unsigned long start)
 		struct page *thp;
 
 		thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
-					 HPAGE_PMD_ORDER);
+					 thp_order(page));
 		if (!thp)
 			return NULL;
 		prep_transhuge_page(thp);
diff --git a/mm/migrate.c b/mm/migrate.c
index 4639dfc2b7ee..b58b96fdb174 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1553,7 +1553,7 @@ struct page *alloc_migration_target(struct page *page, unsigned long private)
 		 */
 		gfp_mask &= ~__GFP_RECLAIM;
 		gfp_mask |= GFP_TRANSHUGE;
-		order = HPAGE_PMD_ORDER;
+		order = thp_order(page);
 	}
 	zidx = zone_idx(page_zone(page));
 	if (is_highmem_idx(zidx) || zidx == ZONE_MOVABLE)
-- 
2.35.1