From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f69.google.com (mail-oi0-f69.google.com [209.85.218.69]) by kanga.kvack.org (Postfix) with ESMTP id 150236B0038 for ; Sun, 16 Oct 2016 22:08:49 -0400 (EDT) Received: by mail-oi0-f69.google.com with SMTP id w11so346121427oia.6 for ; Sun, 16 Oct 2016 19:08:49 -0700 (PDT) Received: from szxga03-in.huawei.com ([119.145.14.66]) by mx.google.com with ESMTPS id p41si10316477otc.1.2016.10.16.19.08.46 for (version=TLS1 cipher=AES128-SHA bits=128/128); Sun, 16 Oct 2016 19:08:48 -0700 (PDT) Message-ID: <5804305F.4030302@huawei.com> Date: Mon, 17 Oct 2016 09:58:55 +0800 From: zhong jiang MIME-Version: 1.0 Subject: Re: [PATCH v2] z3fold: fix the potential encode bug in encod_handle References: <1476331337-17253-1-git-send-email-zhongjiang@huawei.com> In-Reply-To: <1476331337-17253-1-git-send-email-zhongjiang@huawei.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: vitalywool@gmail.com, david@fromorbit.com, sjenning@redhat.com, ddstreet@ieee.org, akpm@linux-foundation.org, mhocko@kernel.org, vbabka@suse.cz Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org Hi, Vitaly About the following patch, is it right? Thanks zhongjiang On 2016/10/13 12:02, zhongjiang wrote: > From: zhong jiang > > At present, zhdr->first_num plus bud can exceed the BUDDY_MASK > in encode_handle, it will lead to the the caller handle_to_buddy > return the error value. > > The patch fix the issue by changing the BUDDY_MASK to PAGE_MASK, > it will be consistent with handle_to_z3fold_header. At the same time, > change the BUDDY_MASK to PAGE_MASK in handle_to_buddy is better. > > Signed-off-by: zhong jiang > --- > mm/z3fold.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/z3fold.c b/mm/z3fold.c > index 8f9e89c..e8fc216 100644 > --- a/mm/z3fold.c > +++ b/mm/z3fold.c > @@ -169,7 +169,7 @@ static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) > > handle = (unsigned long)zhdr; > if (bud != HEADLESS) > - handle += (bud + zhdr->first_num) & BUDDY_MASK; > + handle += (bud + zhdr->first_num) & PAGE_MASK; > return handle; > } > > @@ -183,7 +183,7 @@ static struct z3fold_header *handle_to_z3fold_header(unsigned long handle) > static enum buddy handle_to_buddy(unsigned long handle) > { > struct z3fold_header *zhdr = handle_to_z3fold_header(handle); > - return (handle - zhdr->first_num) & BUDDY_MASK; > + return (handle - zhdr->first_num) & PAGE_MASK; > } > > /* -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org