From 3e2af7a7df6ab3d1b06d7411916f4b737708b9eb Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Fri, 29 Apr 2022 14:40:43 +0800 Subject: [PATCH] mm/z3fold: remove buggy use of stale list for allocation Currently if z3fold couldn't find an unbuddied page it would first try to pull a page off the stale list. But this approach is problematic. If init z3fold page fails later, the page should be freed via free_z3fold_page to clean up the relevant resource instead of using __free_page directly. And if page is successfully reused, it will BUG_ON later in __SetPageMovable because it's already non-lru movable page, i.e. PAGE_MAPPING_MOVABLE is already set in page->mapping. In order to fix all of these issues, we can simply remove the buggy use of stale list for allocation because can_sleep should always be false and we never really hit the reusing code path now. Link: https://lkml.kernel.org/r/20220429064051.61552-4-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reviewed-by: Vitaly Wool Signed-off-by: Andrew Morton --- mm/z3fold.c | 23 +---------------------- 1 file changed, 1 insertion(+), 22 deletions(-) diff --git a/mm/z3fold.c b/mm/z3fold.c index 5d8c21f2bc592..4e6814c5694fa 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -1102,28 +1102,7 @@ retry: bud = FIRST; } - page = NULL; - if (can_sleep) { - spin_lock(&pool->stale_lock); - zhdr = list_first_entry_or_null(&pool->stale, - struct z3fold_header, buddy); - /* - * Before allocating a page, let's see if we can take one from - * the stale pages list. cancel_work_sync() can sleep so we - * limit this case to the contexts where we can sleep - */ - if (zhdr) { - list_del(&zhdr->buddy); - spin_unlock(&pool->stale_lock); - cancel_work_sync(&zhdr->work); - page = virt_to_page(zhdr); - } else { - spin_unlock(&pool->stale_lock); - } - } - if (!page) - page = alloc_page(gfp); - + page = alloc_page(gfp); if (!page) return -ENOMEM; -- 2.39.5