[v9,mm-unstable,11/18] mm/zsmalloc: convert reset_page to reset_zpdesc

Commit Message

Hyeonggon Yoo Dec. 16, 2024, 3:04 p.m. UTC

From: Alex Shi <[e-mail]>

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.

Since the fields that need to be initialized are independent of the
order in struct zpdesc, Keep it to use struct page to ensure robustness
against potential rearrangements of struct zpdesc fields in the future.

[42.hyeyoo: keep reset_zpdesc() to use struct page fields]
Signed-off-by: Alex Shi <[e-mail]>
Signed-off-by: Hyeonggon Yoo <[e-mail]>
---
 mm/zsmalloc.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Patch

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 432e78e61d2e..dded6d1f3b7a 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -843,8 +843,10 @@  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);
@@ -887,7 +889,7 @@  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);
@@ -1865,7 +1867,7 @@  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;