mm: simplify calling a compound page destructor

None of the three callers of get_compound_page_dtor() want to know the
value; they just want to call the function.  Replace it with
destroy_compound_page() which calls the dtor for them.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Link: http://lkml.kernel.org/r/20200517105051.9352-1-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/swap.c b/mm/swap.c
index 0ac463d..6e454a5 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -102,8 +102,6 @@ static void __put_single_page(struct page *page)
 
 static void __put_compound_page(struct page *page)
 {
-	compound_page_dtor *dtor;
-
 	/*
 	 * __page_cache_release() is supposed to be called for thp, not for
 	 * hugetlb. This is because hugetlb page does never have PageLRU set
@@ -112,8 +110,7 @@ static void __put_compound_page(struct page *page)
 	 */
 	if (!PageHuge(page))
 		__page_cache_release(page);
-	dtor = get_compound_page_dtor(page);
-	(*dtor)(page);
+	destroy_compound_page(page);
 }
 
 void __put_page(struct page *page)