mm: move folio_set_compound_order() to mm/internal.h

folio_set_compound_order() is moved to an mm-internal location so external
folio users cannot misuse this function.  Change the name of the function
to folio_set_order() and use WARN_ON_ONCE() rather than BUG_ON.  Also,
handle the case if a non-large folio is passed and add clarifying comments
to the function.

Link: https://lore.kernel.org/lkml/20221207223731.32784-1-sidhartha.kumar@oracle.com/T/
Link: https://lkml.kernel.org/r/20221215061757.223440-1-sidhartha.kumar@oracle.com
Fixes: 9fd330582b2f ("mm: add folio dtor and order setter functions")
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Suggested-by: Muchun Song <songmuchun@bytedance.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Suggested-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index bdbfeb6fb393..cfd47a66ded0 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1492,7 +1492,7 @@ static void __destroy_compound_gigantic_folio(struct folio *folio,
 			set_page_refcounted(p);
 	}
 
-	folio_set_compound_order(folio, 0);
+	folio_set_order(folio, 0);
 	__folio_clear_head(folio);
 }
 
@@ -1956,7 +1956,7 @@ static bool __prep_compound_gigantic_folio(struct folio *folio,
 	__folio_clear_reserved(folio);
 	__folio_set_head(folio);
 	/* we rely on prep_new_hugetlb_folio to set the destructor */
-	folio_set_compound_order(folio, order);
+	folio_set_order(folio, order);
 	for (i = 0; i < nr_pages; i++) {
 		p = folio_page(folio, i);
 
@@ -2020,7 +2020,7 @@ out_error:
 		p = folio_page(folio, j);
 		__ClearPageReserved(p);
 	}
-	folio_set_compound_order(folio, 0);
+	folio_set_order(folio, 0);
 	__folio_clear_head(folio);
 	return false;
 }