From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9F81C4708F for ; Tue, 1 Jun 2021 08:46:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B96A661375 for ; Tue, 1 Jun 2021 08:46:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233330AbhFAIsX (ORCPT ); Tue, 1 Jun 2021 04:48:23 -0400 Received: from mx2.suse.de ([195.135.220.15]:49716 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233157AbhFAIsW (ORCPT ); Tue, 1 Jun 2021 04:48:22 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1622537200; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ACL4QuiSE0koEi+rfHcLVpupQtHQPyQnD2Exg+8O9N8=; b=l7DLNTWaNkYKmVbZV81wMUP2kX5fCG7TXxsgnJZ99xkqBSnvM/SxiLMQ7mWOKdYT4+MCYT 2kaUT7JmskPUmDSgDBZwaFL9VkkNDMeUOJlaWWG4hZEMVJI5FjxwPbzXdA7Vd80eqSbYlb feXoTKMsEyz1UlHRlj8Vkf14wXD7RDw= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 58280AE78; Tue, 1 Jun 2021 08:46:40 +0000 (UTC) Date: Tue, 1 Jun 2021 10:46:39 +0200 From: Michal Hocko To: Feng Tang Cc: linux-mm@kvack.org, Andrew Morton , David Rientjes , Dave Hansen , Ben Widawsky , linux-kernel@vger.kernel.org, Andrea Arcangeli , Mel Gorman , Mike Kravetz , Randy Dunlap , Vlastimil Babka , Andi Kleen , Dan Williams , ying.huang@intel.com Subject: Re: [v3 PATCH 3/3] mm/mempolicy: unify the parameter sanity check for mbind and set_mempolicy Message-ID: References: <1622469956-82897-1-git-send-email-feng.tang@intel.com> <1622469956-82897-4-git-send-email-feng.tang@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1622469956-82897-4-git-send-email-feng.tang@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 31-05-21 22:05:56, Feng Tang wrote: > Currently the kernel_mbind() and kernel_set_mempolicy() do almost > the same operation for parameter sanity check. > > Add a helper function to unify the code to reduce the redundancy, > and make it easier for changing the pre-processing code in future. > > [thanks to David Rientjes for suggesting using helper function > instead of macro] > > Signed-off-by: Feng Tang sanitize_mpol_flags would benefit from some high level comments explaining those modifications but this can be done on top. This looks like a useful cleanup on its own Acked-by: Michal Hocko Thanks! > --- > mm/mempolicy.c | 47 +++++++++++++++++++++++++++++------------------ > 1 file changed, 29 insertions(+), 18 deletions(-) > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index c337bd7..85ef512 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -1444,26 +1444,37 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode, > return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0; > } > > +static inline int sanitize_mpol_flags(int *mode, unsigned short *flags) > +{ > + *flags = *mode & MPOL_MODE_FLAGS; > + *mode &= ~MPOL_MODE_FLAGS; > + if ((unsigned int)(*mode) >= MPOL_MAX) > + return -EINVAL; > + if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES)) > + return -EINVAL; > + > + return 0; > +} > + > static long kernel_mbind(unsigned long start, unsigned long len, > unsigned long mode, const unsigned long __user *nmask, > unsigned long maxnode, unsigned int flags) > { > + unsigned short mode_flags; > nodemask_t nodes; > + int lmode = mode; > int err; > - unsigned short mode_flags; > > start = untagged_addr(start); > - mode_flags = mode & MPOL_MODE_FLAGS; > - mode &= ~MPOL_MODE_FLAGS; > - if (mode >= MPOL_MAX) > - return -EINVAL; > - if ((mode_flags & MPOL_F_STATIC_NODES) && > - (mode_flags & MPOL_F_RELATIVE_NODES)) > - return -EINVAL; > + err = sanitize_mpol_flags(&lmode, &mode_flags); > + if (err) > + return err; > + > err = get_nodes(&nodes, nmask, maxnode); > if (err) > return err; > - return do_mbind(start, len, mode, mode_flags, &nodes, flags); > + > + return do_mbind(start, len, lmode, mode_flags, &nodes, flags); > } > > SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len, > @@ -1477,20 +1488,20 @@ SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len, > static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask, > unsigned long maxnode) > { > - int err; > + unsigned short mode_flags; > nodemask_t nodes; > - unsigned short flags; > + int lmode = mode; > + int err; > + > + err = sanitize_mpol_flags(&lmode, &mode_flags); > + if (err) > + return err; > > - flags = mode & MPOL_MODE_FLAGS; > - mode &= ~MPOL_MODE_FLAGS; > - if ((unsigned int)mode >= MPOL_MAX) > - return -EINVAL; > - if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES)) > - return -EINVAL; > err = get_nodes(&nodes, nmask, maxnode); > if (err) > return err; > - return do_set_mempolicy(mode, flags, &nodes); > + > + return do_set_mempolicy(lmode, mode_flags, &nodes); > } > > SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask, > -- > 2.7.4 -- Michal Hocko SUSE Labs