[PATCH v8 11/21] mm/zsmalloc: rename reset_page to reset_zpdesc and use zpdesc in it

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

From: Alex Shi <alexs@kernel.org>

zpdesc.zspage matches with page.private, zpdesc.next matches with
page.index. They will be reset in reset_page() which is called prior to
free base pages of a zspage.
Use zpdesc to replace page struct and rename it to reset_zpdesc(), few
page helper still left since they are used too widely.

Signed-off-by: Alex Shi <alexs@kernel.org>
---
 mm/zsmalloc.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index d8f2f8e5c877..87b2b100782f 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -861,12 +861,14 @@ static inline bool obj_allocated(struct zpdesc *zpdesc, void *obj,
 	return true;
 }
 
-static void reset_page(struct page *page)
+static void reset_zpdesc(struct zpdesc *zpdesc)
 {
+	struct page *page = zpdesc_page(zpdesc);
+
 	__ClearPageMovable(page);
 	ClearPagePrivate(page);
-	set_page_private(page, 0);
-	page->index = 0;
+	zpdesc->zspage = NULL;
+	zpdesc->next = NULL;
 	__ClearPageZsmalloc(page);
 }
 
@@ -905,7 +907,7 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class,
 	do {
 		VM_BUG_ON_PAGE(!PageLocked(page), page);
 		next = get_next_page(page);
-		reset_page(page);
+		reset_zpdesc(page_zpdesc(page));
 		unlock_page(page);
 		dec_zone_page_state(page, NR_ZSPAGES);
 		put_page(page);
@@ -1884,7 +1886,7 @@ static int zs_page_migrate(struct page *newpage, struct page *page,
 		zpdesc_inc_zone_page_state(newzpdesc);
 	}
 
-	reset_page(page);
+	reset_zpdesc(zpdesc);
 	zpdesc_put(zpdesc);
 
 	return MIGRATEPAGE_SUCCESS;
-- 
2.45.2