Commit 73349afa authored Dec 17, 2024 by Alex Shi Committed by Andrew Morton Jan 25, 2025

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>

parent 68721300

mm/zsmalloc.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -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;