From: Alex Shi <alexs@kernel.org>
Date: Mon, 16 Dec 2024 15:04:42 +0000 (+0900)
Subject: mm/zsmalloc: convert reset_page to reset_zpdesc
X-Git-Tag: v6.14-rc1~77^2~84
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=73349afa00419585c11ee232377879b1f2912881;p=thirdparty%2Fkernel%2Flinux.git

mm/zsmalloc: convert reset_page to reset_zpdesc

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@gmail.com: reset zpdesc fields in reset_zpdesc()]
  Link: https://lkml.kernel.org/r/Z4Uw136VdG7vlKCL@localhost.localdomain
[42.hyeyoo@gmail.com: keep reset_zpdesc() to use struct page fields]
Link: https://lkml.kernel.org/r/20241216150450.1228021-12-42.hyeyoo@gmail.com
Signed-off-by: Alex Shi <alexs@kernel.org>
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Acked-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Tested-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 432e78e61d2e3..98b152a0b2643 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -843,12 +843,14 @@ 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);
 }
 
@@ -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;