From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751949AbdJaIzl (ORCPT ); Tue, 31 Oct 2017 04:55:41 -0400 Received: from mx2.suse.de ([195.135.220.15]:50488 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750978AbdJaIzh (ORCPT ); Tue, 31 Oct 2017 04:55:37 -0400 Subject: Re: [PATCH RFC v2 2/4] mm/mempolicy: remove redundant check in get_nodes To: Yisheng Xie , akpm@linux-foundation.org, mhocko@suse.com, mingo@kernel.org, rientjes@google.com, n-horiguchi@ah.jp.nec.com, salls@cs.ucsb.edu Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, tanxiaojun@huawei.com, linux-api@vger.kernel.org References: <1509099265-30868-1-git-send-email-xieyisheng1@huawei.com> <1509099265-30868-3-git-send-email-xieyisheng1@huawei.com> From: Vlastimil Babka Message-ID: <61a0b15c-8a68-230a-5f5b-3f5025dff24a@suse.cz> Date: Tue, 31 Oct 2017 09:55:35 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1509099265-30868-3-git-send-email-xieyisheng1@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/27/2017 12:14 PM, Yisheng Xie wrote: > We have already checked whether maxnode is a page worth of bits, by: > maxnode > PAGE_SIZE*BITS_PER_BYTE > > So no need to check it once more. > > Signed-off-by: Yisheng Xie Acked-by: Vlastimil Babka > --- > mm/mempolicy.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index 613e9d0..3b51bb3 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -1280,8 +1280,6 @@ static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask, > /* When the user specified more nodes than supported just check > if the non supported part is all zero. */ > if (nlongs > BITS_TO_LONGS(MAX_NUMNODES)) { > - if (nlongs > PAGE_SIZE/sizeof(long)) > - return -EINVAL; > for (k = BITS_TO_LONGS(MAX_NUMNODES); k < nlongs; k++) { > unsigned long t; > if (get_user(t, nmask + k)) >