[PATCH 07/12] mm: Make large folios depend on THP

[Matthew Wilcox (Oracle)]

Some parts of the VM still depend on THP to handle large folios
correctly.  Until those are fixed, prevent creating large folios
if THP are disabled.

Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
 include/linux/pagemap.h | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 877dabed0316..3e348e0a9e4e 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -192,9 +192,14 @@ static inline void mapping_set_large_folios(struct address_space *mapping)
 	__set_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
 }
 
+/*
+ * Large folio support currently depends on THP.  These dependencies are
+ * being worked on but are not yet fixed.
+ */
 static inline bool mapping_large_folio_support(struct address_space *mapping)
 {
-	return test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
+	return IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
+		test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags);
 }
 
 static inline int filemap_nr_thps(struct address_space *mapping)
-- 
2.34.1