[PATCH v1 06/10] mm/huge_memory: remove folio split check for READ_ONLY_THP_FOR_FS

[Zi Yan]

Without READ_ONLY_THP_FOR_FS, large file-backed folios cannot be created by
a FS without large folio support. The check is no longer needed.

Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
 mm/huge_memory.c | 22 ----------------------
 1 file changed, 22 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1da1467328a3..30eddcbf86f1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3732,28 +3732,6 @@ int folio_check_splittable(struct folio *folio, unsigned int new_order,
 		/* order-1 is not supported for anonymous THP. */
 		if (new_order == 1)
 			return -EINVAL;
-	} else if (split_type == SPLIT_TYPE_NON_UNIFORM || new_order) {
-		if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) &&
-		    !mapping_large_folio_support(folio->mapping)) {
-			/*
-			 * We can always split a folio down to a single page
-			 * (new_order == 0) uniformly.
-			 *
-			 * For any other scenario
-			 *   a) uniform split targeting a large folio
-			 *      (new_order > 0)
-			 *   b) any non-uniform split
-			 * we must confirm that the file system supports large
-			 * folios.
-			 *
-			 * Note that we might still have THPs in such
-			 * mappings, which is created from khugepaged when
-			 * CONFIG_READ_ONLY_THP_FOR_FS is enabled. But in that
-			 * case, the mapping does not actually support large
-			 * folios properly.
-			 */
-			return -EINVAL;
-		}
 	}
 
 	/*
-- 
2.43.0