[patch 092/167] mm/page_alloc.c: use a single function to free page

[akpm@xxxxxxxxxxxxxxxxxxxx]

From: Aaron Lu <aaron.lu@xxxxxxxxx>
Subject: mm/page_alloc.c: use a single function to free page

There are multiple places of freeing a page, they all do the same things
so a common function can be used to reduce code duplicate.

It also avoids bug fixed in one function but left in another.

Link: http://lkml.kernel.org/r/20181119134834.17765-3-aaron.lu@xxxxxxxxx
Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Cc: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx>
Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Pankaj gupta <pagupta@xxxxxxxxxx>
Cc: Pawel Staszewski <pstaszewski@xxxxxxxxx>
Cc: Tariq Toukan <tariqt@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---


--- a/mm/page_alloc.c~mm-page_alloc-use-a-single-function-to-free-page
+++ a/mm/page_alloc.c
@@ -4427,16 +4427,19 @@ unsigned long get_zeroed_page(gfp_t gfp_
 }
 EXPORT_SYMBOL(get_zeroed_page);
 
-void __free_pages(struct page *page, unsigned int order)
+static inline void free_the_page(struct page *page, unsigned int order)
 {
-	if (put_page_testzero(page)) {
-		if (order == 0)
-			free_unref_page(page);
-		else
-			__free_pages_ok(page, order);
-	}
+	if (order == 0)		/* Via pcp? */
+		free_unref_page(page);
+	else
+		__free_pages_ok(page, order);
 }
 
+void __free_pages(struct page *page, unsigned int order)
+{
+	if (put_page_testzero(page))
+		free_the_page(page, order);
+}
 EXPORT_SYMBOL(__free_pages);
 
 void free_pages(unsigned long addr, unsigned int order)
@@ -4485,14 +4488,8 @@ void __page_frag_cache_drain(struct page
 {
 	VM_BUG_ON_PAGE(page_ref_count(page) == 0, page);
 
-	if (page_ref_sub_and_test(page, count)) {
-		unsigned int order = compound_order(page);
-
-		if (order == 0)
-			free_unref_page(page);
-		else
-			__free_pages_ok(page, order);
-	}
+	if (page_ref_sub_and_test(page, count))
+		free_the_page(page, compound_order(page));
 }
 EXPORT_SYMBOL(__page_frag_cache_drain);
 
@@ -4557,14 +4554,8 @@ void page_frag_free(void *addr)
 {
 	struct page *page = virt_to_head_page(addr);
 
-	if (unlikely(put_page_testzero(page))) {
-		unsigned int order = compound_order(page);
-
-		if (order == 0)		/* Via pcp? */
-			free_unref_page(page);
-		else
-			__free_pages_ok(page, order);
-	}
+	if (unlikely(put_page_testzero(page)))
+		free_the_page(page, compound_order(page));
 }
 EXPORT_SYMBOL(page_frag_free);
 
_