[PATCH 2/2] mm/mm.h: Write folio->_flags_1 & 0xff as a macro definition

[Liu Ye <liuye@kylinos.cn>]

There are multiple locations in mm.h where (folio->_flags_1 & 0xff) is
used. Write it as a macro definition to improve the readability and
maintainability of the code.

Signed-off-by: Liu Ye <liuye@kylinos.cn>
---
 include/linux/mm.h | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7b1068ddcbb7..750e75f45557 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1098,6 +1098,8 @@ int vma_is_stack_for_current(struct vm_area_struct *vma);
 struct mmu_gather;
 struct inode;
 
+#define FOLIO_ORDER(folio) ((folio)->_flags_1 & 0xff)
+
 /*
  * compound_order() can be called without holding a reference, which means
  * that niceties like page_folio() don't work.  These callers should be
@@ -1111,7 +1113,7 @@ static inline unsigned int compound_order(struct page *page)
 
 	if (!test_bit(PG_head, &folio->flags))
 		return 0;
-	return folio->_flags_1 & 0xff;
+	return FOLIO_ORDER(folio);
 }
 
 /**
@@ -1127,7 +1129,7 @@ static inline unsigned int folio_order(const struct folio *folio)
 {
 	if (!folio_test_large(folio))
 		return 0;
-	return folio->_flags_1 & 0xff;
+	return FOLIO_ORDER(folio);
 }
 
 #include <linux/huge_mm.h>
@@ -2061,7 +2063,7 @@ static inline long folio_nr_pages(const struct folio *folio)
 #ifdef CONFIG_64BIT
 	return folio->_folio_nr_pages;
 #else
-	return 1L << (folio->_flags_1 & 0xff);
+	return 1L << FOLIO_ORDER(folio);
 #endif
 }
 
@@ -2086,7 +2088,7 @@ static inline unsigned long compound_nr(struct page *page)
 #ifdef CONFIG_64BIT
 	return folio->_folio_nr_pages;
 #else
-	return 1L << (folio->_flags_1 & 0xff);
+	return 1L << FOLIO_ORDER(folio);
 #endif
 }
 
-- 
2.25.1