From 929e4c3534ecdc6c11921dff5a54597c5d61ca6a Mon Sep 17 00:00:00 2001 From: Zhongkun He Date: Mon, 19 Feb 2024 10:44:53 +0800 Subject: [PATCH] mm/z3fold: fix the comment for __encode_handle() The comment is confusing that Pool lock should be held as this function accesses first_num above the __encode_handle() because first_num is the element of z3fold_header which is protected by z3fold_header->page_lock. I found the same comment for encode_handle() in zbud.c by accident ,Pool lock should be held as this function accesses first|last_chunks, which is the element of zbud_header and it does not have any lock, so pool lock should be held. Z3fold is based on zbud, maybe the comment come from zbud, but it was wrong, so fix it. Link: https://lkml.kernel.org/r/20240219024453.2240147-1-hezhongkun.hzk@bytedance.com Signed-off-by: Zhongkun He Cc: Johannes Weiner Cc: Miaohe Lin Cc: Vitaly Wool Signed-off-by: Andrew Morton --- mm/z3fold.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/mm/z3fold.c b/mm/z3fold.c index 7c76b396b74c..7ab05621052d 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -364,8 +364,9 @@ static inline int __idx(struct z3fold_header *zhdr, enum buddy bud) } /* - * Encodes the handle of a particular buddy within a z3fold page - * Pool lock should be held as this function accesses first_num + * Encodes the handle of a particular buddy within a z3fold page. + * Zhdr->page_lock should be held as this function accesses first_num + * if bud != HEADLESS. */ static unsigned long __encode_handle(struct z3fold_header *zhdr, struct z3fold_buddy_slots *slots,