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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5AB8EC433F5 for ; Thu, 17 Feb 2022 13:29:04 +0000 (UTC) Received: from localhost ([::1]:59722 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nKgqF-00072m-6j for qemu-devel@archiver.kernel.org; Thu, 17 Feb 2022 08:29:03 -0500 Received: from eggs.gnu.org ([209.51.188.92]:51724) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nKgLi-0002eT-KJ for qemu-devel@nongnu.org; Thu, 17 Feb 2022 07:57:32 -0500 Received: from mga14.intel.com ([192.55.52.115]:55807) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nKgLg-0002nz-H4 for qemu-devel@nongnu.org; Thu, 17 Feb 2022 07:57:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1645102648; x=1676638648; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=muUyZFkT/XUwYXtZ4KuQ8w3WazrYqWNDm8XTjig5hYY=; b=D91GABD51DROhfeANHHG8jAUDtT3oatQtbYw/rG8sN8cZ+GTVWQyPqoe SI85fyFhNmEF3bjxd+5yiFfy8yeChnDp/ANL/lkU0Pg3f1veQx9UaBA8x 3HJucDSfeWJM8kXv4hHNnonQ73YOLBOXJFA0ybwISOqjFDPXPh4LpJ5OM AXI56ZSEj8GbAbPLJXdBN9QRH4NdjhOVgevlOpTxFwTPJVNP32kzZaBdz ZZ8f8y+H2btbI996qUsCzXAi8i779Ez4M5oHxjaN6MUdKzUH4Ewphe3CX B7UNHDIpBBuPm21RFTVIuROD7AKjH2Iat8zWmIx2EVwP/E41DarCl/1HA A==; X-IronPort-AV: E=McAfee;i="6200,9189,10260"; a="251064852" X-IronPort-AV: E=Sophos;i="5.88,375,1635231600"; d="scan'208";a="251064852" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2022 04:57:25 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,375,1635231600"; d="scan'208";a="704785987" Received: from chaop.bj.intel.com (HELO localhost) ([10.240.192.101]) by orsmga005.jf.intel.com with ESMTP; 17 Feb 2022 04:57:18 -0800 Date: Thu, 17 Feb 2022 20:56:57 +0800 From: Chao Peng To: Vlastimil Babka Subject: Re: [PATCH v4 01/12] mm/shmem: Introduce F_SEAL_INACCESSIBLE Message-ID: <20220217125656.GA32679@chaop.bj.intel.com> References: <20220118132121.31388-1-chao.p.peng@linux.intel.com> <20220118132121.31388-2-chao.p.peng@linux.intel.com> <64407833-1387-0c46-c569-8b6a3db8e88c@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <64407833-1387-0c46-c569-8b6a3db8e88c@suse.cz> User-Agent: Mutt/1.9.4 (2018-02-28) Received-SPF: none client-ip=192.55.52.115; envelope-from=chao.p.peng@linux.intel.com; helo=mga14.intel.com X-Spam_score_int: -70 X-Spam_score: -7.1 X-Spam_bar: ------- X-Spam_report: (-7.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_NONE=0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Chao Peng Cc: Wanpeng Li , jun.nakajima@intel.com, kvm@vger.kernel.org, david@redhat.com, qemu-devel@nongnu.org, "J . Bruce Fields" , linux-mm@kvack.org, "H . Peter Anvin" , ak@linux.intel.com, Jonathan Corbet , Joerg Roedel , x86@kernel.org, Hugh Dickins , Ingo Molnar , Borislav Petkov , luto@kernel.org, Thomas Gleixner , Vitaly Kuznetsov , Jim Mattson , dave.hansen@intel.com, Sean Christopherson , Jeff Layton , linux-kernel@vger.kernel.org, Yu Zhang , linux-fsdevel@vger.kernel.org, Paolo Bonzini , Andrew Morton , "Kirill A . Shutemov" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Feb 07, 2022 at 01:24:42PM +0100, Vlastimil Babka wrote: > On 1/18/22 14:21, Chao Peng wrote: > > From: "Kirill A. Shutemov" > > > > /* > > diff --git a/mm/shmem.c b/mm/shmem.c > > index 18f93c2d68f1..72185630e7c4 100644 > > --- a/mm/shmem.c > > +++ b/mm/shmem.c > > @@ -1098,6 +1098,13 @@ static int shmem_setattr(struct user_namespace *mnt_userns, > > (newsize > oldsize && (info->seals & F_SEAL_GROW))) > > return -EPERM; > > > > + if (info->seals & F_SEAL_INACCESSIBLE) { > > + if(i_size_read(inode)) > > Is this needed? The rest of the function seems to trust oldsize obtained by > plain reading inode->i_size well enough, so why be suddenly paranoid here? oldsize sounds enough here, unless kirill has different mind. > > > + return -EPERM; > > + if (newsize & ~PAGE_MASK) > > + return -EINVAL; > > + } > > + > > if (newsize != oldsize) { > > error = shmem_reacct_size(SHMEM_I(inode)->flags, > > + if ((info->seals & F_SEAL_INACCESSIBLE) && > > + (offset & ~PAGE_MASK || len & ~PAGE_MASK)) { > > Could we use PAGE_ALIGNED()? Yes, definitely, thanks. Chao > > > + error = -EINVAL; > > + goto out; > > + } > > + > > shmem_falloc.waitq = &shmem_falloc_waitq; > > shmem_falloc.start = (u64)unmap_start >> PAGE_SHIFT; > > shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT;