mm/folio: replace set_compound_order with folio_set_order

The patch ("mm/folio: Avoid special handling for order value 0 in
folio_set_order") [1] removed the need for special handling of order = 0
in folio_set_order.  Now, folio_set_order and set_compound_order becomes
similar function.  This patch removes the set_compound_order and uses
folio_set_order instead.

[1] https://lore.kernel.org/all/[email protected]/

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Tarun Sahu <[email protected]>
Reviewed-by Sidhartha Kumar <[email protected]>
Reviewed-by: Muchun Song <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Gerald Schaefer <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Mike Kravetz <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

include/linux/mm.h

@@ -1232,16 +1232,6 @@ static inline void folio_set_compound_dtor(struct folio *folio,
 
 void destroy_large_folio(struct folio *folio);
 
-static inline void set_compound_order(struct page *page, unsigned int order)
-{
-	struct folio *folio = (struct folio *)page;
-
-	folio->_folio_order = order;
-#ifdef CONFIG_64BIT
-	folio->_folio_nr_pages = 1U << order;
-#endif
-}
-
 /* Returns the number of bytes in this potentially compound page. */
 static inline unsigned long page_size(struct page *page)
 {

mm/internal.h

@@ -387,12 +387,27 @@ extern void memblock_free_pages(struct page *page, unsigned long pfn,
 					unsigned int order);
 extern void __free_pages_core(struct page *page, unsigned int order);
 
+/*
+ * This will have no effect, other than possibly generating a warning, if the
+ * caller passes in a non-large folio.
+ */
+static inline void folio_set_order(struct folio *folio, unsigned int order)
+{
+	if (WARN_ON_ONCE(!order || !folio_test_large(folio)))
+		return;
+
+	folio->_folio_order = order;
+#ifdef CONFIG_64BIT
+	folio->_folio_nr_pages = 1U << order;
+#endif
+}
+
 static inline void prep_compound_head(struct page *page, unsigned int order)
 {
 	struct folio *folio = (struct folio *)page;
 
 	folio_set_compound_dtor(folio, COMPOUND_PAGE_DTOR);
-	set_compound_order(page, order);
+	folio_set_order(folio, order);
 	atomic_set(&folio->_entire_mapcount, -1);
 	atomic_set(&folio->_nr_pages_mapped, 0);
 	atomic_set(&folio->_pincount, 0);
@@ -432,21 +447,6 @@ void memmap_init_range(unsigned long, int, unsigned long, unsigned long,
 int split_free_page(struct page *free_page,
 			unsigned int order, unsigned long split_pfn_offset);
 
-/*
- * This will have no effect, other than possibly generating a warning, if the
- * caller passes in a non-large folio.
- */
-static inline void folio_set_order(struct folio *folio, unsigned int order)
-{
-	if (WARN_ON_ONCE(!order || !folio_test_large(folio)))
-		return;
-
-	folio->_folio_order = order;
-#ifdef CONFIG_64BIT
-	folio->_folio_nr_pages = 1U << order;
-#endif
-}
-
 #if defined CONFIG_COMPACTION || defined CONFIG_CMA
 
 /*