mm: combine free_the_page() and free_unref_page()

The pcp_allowed_order() check in free_the_page() was only being skipped by
__folio_put_small() which is about to be rearranged.

Link: https://lkml.kernel.org/r/20240405153228.2563754-3-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/page_alloc.c

@@ -541,14 +541,6 @@ static inline bool pcp_allowed_order(unsigned int order)
 	return false;
 }
 
-static inline void free_the_page(struct page *page, unsigned int order)
-{
-	if (pcp_allowed_order(order))		/* Via pcp? */
-		free_unref_page(page, order);
-	else
-		__free_pages_ok(page, order, FPI_NONE);
-}
-
 /*
  * Higher-order pages are called "compound pages".  They are structured thusly:
  *
@@ -584,7 +576,7 @@ void destroy_large_folio(struct folio *folio)
 		folio_undo_large_rmappable(folio);
 
 	mem_cgroup_uncharge(folio);
-	free_the_page(&folio->page, folio_order(folio));
+	free_unref_page(&folio->page, folio_order(folio));
 }
 
 static inline void set_buddy_order(struct page *page, unsigned int order)
@@ -2573,6 +2565,11 @@ void free_unref_page(struct page *page, unsigned int order)
 	unsigned long pfn = page_to_pfn(page);
 	int migratetype;
 
+	if (!pcp_allowed_order(order)) {
+		__free_pages_ok(page, order, FPI_NONE);
+		return;
+	}
+
 	if (!free_pages_prepare(page, order))
 		return;
 
@@ -4755,11 +4752,11 @@ void __free_pages(struct page *page, unsigned int order)
 	struct alloc_tag *tag = pgalloc_tag_get(page);
 
 	if (put_page_testzero(page))
-		free_the_page(page, order);
+		free_unref_page(page, order);
 	else if (!head) {
 		pgalloc_tag_sub_pages(tag, (1 << order) - 1);
 		while (order-- > 0)
-			free_the_page(page + (1 << order), order);
+			free_unref_page(page + (1 << order), order);
 	}
 }
 EXPORT_SYMBOL(__free_pages);
@@ -4821,7 +4818,7 @@ void __page_frag_cache_drain(struct page *page, unsigned int count)
 	VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
 
 	if (page_ref_sub_and_test(page, count))
-		free_the_page(page, compound_order(page));
+		free_unref_page(page, compound_order(page));
 }
 EXPORT_SYMBOL(__page_frag_cache_drain);
 
@@ -4862,7 +4859,7 @@ void *__page_frag_alloc_align(struct page_frag_cache *nc,
 			goto refill;
 
 		if (unlikely(nc->pfmemalloc)) {
-			free_the_page(page, compound_order(page));
+			free_unref_page(page, compound_order(page));
 			goto refill;
 		}
 
@@ -4906,7 +4903,7 @@ void page_frag_free(void *addr)
 	struct page *page = virt_to_head_page(addr);
 
 	if (unlikely(put_page_testzero(page)))
-		free_the_page(page, compound_order(page));
+		free_unref_page(page, compound_order(page));
 }
 EXPORT_SYMBOL(page_frag_free);