mm: combine __folio_put_small, __folio_put_large and __folio_put

It's now obvious that __folio_put_small() and __folio_put_large() do
almost exactly the same thing.  Inline them both into __folio_put().

Link: https://lkml.kernel.org/r/20240405153228.2563754-5-willy@infradead.orgSigned-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/swap.c

@@ -112,42 +112,22 @@ static void page_cache_release(struct folio *folio)
 		unlock_page_lruvec_irqrestore(lruvec, flags);
 }
 
-static void __folio_put_small(struct folio *folio)
-{
-	page_cache_release(folio);
-	mem_cgroup_uncharge(folio);
-	free_unref_page(&folio->page, 0);
-}
-
-static void __folio_put_large(struct folio *folio)
+void __folio_put(struct folio *folio)
 {
-	/*
-	 * __page_cache_release() is supposed to be called for thp, not for
-	 * hugetlb. This is because hugetlb page does never have PageLRU set
-	 * (it's never listed to any LRU lists) and no memcg routines should
-	 * be called for hugetlb (it has a separate hugetlb_cgroup.)
-	 */
-	if (folio_test_hugetlb(folio)) {
+	if (unlikely(folio_is_zone_device(folio))) {
+		free_zone_device_page(&folio->page);
+		return;
+	} else if (folio_test_hugetlb(folio)) {
 		free_huge_folio(folio);
 		return;
 	}
 
 	page_cache_release(folio);
-	if (folio_test_large_rmappable(folio))
+	if (folio_test_large(folio) && folio_test_large_rmappable(folio))
 		folio_undo_large_rmappable(folio);
 	mem_cgroup_uncharge(folio);
 	free_unref_page(&folio->page, folio_order(folio));
 }
-
-void __folio_put(struct folio *folio)
-{
-	if (unlikely(folio_is_zone_device(folio)))
-		free_zone_device_page(&folio->page);
-	else if (unlikely(folio_test_large(folio)))
-		__folio_put_large(folio);
-	else
-		__folio_put_small(folio);
-}
 EXPORT_SYMBOL(__folio_put);
 
 /**