From: Miaohe Lin <linmiaohe@huawei.com>
Date: Fri, 29 Apr 2022 06:40:43 +0000 (+0800)
Subject: mm/z3fold: throw warning on failure of trylock_page in z3fold_alloc
X-Git-Tag: v5.19-rc1~119^2~19
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2c0f351434785626beb5cb49962b4e873459fd38;p=thirdparty%2Fkernel%2Flinux.git

mm/z3fold: throw warning on failure of trylock_page in z3fold_alloc

If trylock_page fails, the page won't be non-lru movable page.  When this
page is freed via free_z3fold_page, it will trigger bug on PageMovable
check in __ClearPageMovable.  Throw warning on failure of trylock_page to
guard against such rare case just as what zsmalloc does.

Link: https://lkml.kernel.org/r/20220429064051.61552-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/z3fold.c b/mm/z3fold.c
index 4e6814c5694fa..b3b4e65c107f3 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -1122,10 +1122,9 @@ retry:
 		__SetPageMovable(page, pool->inode->i_mapping);
 		unlock_page(page);
 	} else {
-		if (trylock_page(page)) {
-			__SetPageMovable(page, pool->inode->i_mapping);
-			unlock_page(page);
-		}
+		WARN_ON(!trylock_page(page));
+		__SetPageMovable(page, pool->inode->i_mapping);
+		unlock_page(page);
 	}
 	z3fold_page_lock(zhdr);