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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 498B0C2BC61 for ; Tue, 30 Oct 2018 21:36:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EFF2A2081B for ; Tue, 30 Oct 2018 21:36:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="CwfXroiG" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EFF2A2081B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-security-module-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726991AbeJaGbM (ORCPT ); Wed, 31 Oct 2018 02:31:12 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:32986 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725743AbeJaGbM (ORCPT ); Wed, 31 Oct 2018 02:31:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=aUavaxogKH403XKXRPnEVNz6RyBC+eD5hHVDUeLt+mY=; b=CwfXroiGl1iorCuN3F1tA9J1q DmMej9IeRdtCWzJcrG/znrrZpyrLbDOk53lsMNEfWiA63Uq9/ZeeN2Cu/xjfU4mmH/LaDvJcdYbax A3SIweSwoNRH5EbjUIZKqeiQ7ZYH/ZCBah5Jz5ppBhcd9EsDLaxWE4QGGm2ZXhD/ZycXZnSxehbYZ qVoGadHOYiLfYG1MDVQcVjNeMNQIq8UWJOrb0Nviai2/AG2zrGVxCuIPlqNy+yZnJnzWYPlEmbtmn YiX6eUCXcAQz2rSQYfvlcI/LOYJLDyL1q9knQS/hVljf6eM+cAmWl7Jm95obQtZ7/YDKW4WO5lsB0 AHnRlXlkg==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gHbg5-0004UL-KK; Tue, 30 Oct 2018 21:35:57 +0000 Date: Tue, 30 Oct 2018 14:35:57 -0700 From: Matthew Wilcox To: Igor Stoppa Cc: Tycho Andersen , Andy Lutomirski , Kees Cook , Peter Zijlstra , Mimi Zohar , Dave Chinner , James Morris , Michal Hocko , Kernel Hardening , linux-integrity , linux-security-module , Igor Stoppa , Dave Hansen , Jonathan Corbet , Laura Abbott , Randy Dunlap , Mike Rapoport , "open list:DOCUMENTATION" , LKML , Thomas Gleixner Subject: Re: [PATCH 10/17] prmem: documentation Message-ID: <20181030213557.GE10491@bombadil.infradead.org> References: <20181028183126.GB744@hirez.programming.kicks-ass.net> <40cd77ce-f234-3213-f3cb-0c3137c5e201@gmail.com> <20181030152641.GE8177@hirez.programming.kicks-ass.net> <0A7AFB50-9ADE-4E12-B541-EC7839223B65@amacapital.net> <20181030175814.GB10491@bombadil.infradead.org> <20181030182841.GE7343@cisco> <20181030192021.GC10491@bombadil.infradead.org> <9edbdf8b-b5fb-5a82-43b4-b639f5ec8484@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9edbdf8b-b5fb-5a82-43b4-b639f5ec8484@gmail.com> User-Agent: Mutt/1.9.2 (2017-12-15) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Tue, Oct 30, 2018 at 10:43:14PM +0200, Igor Stoppa wrote: > On 30/10/2018 21:20, Matthew Wilcox wrote: > > > > So the API might look something like this: > > > > > > > > void *p = rare_alloc(...); /* writable pointer */ > > > > p->a = x; > > > > q = rare_protect(p); /* read-only pointer */ > > With pools and memory allocated from vmap_areas, I was able to say > > protect(pool) > > and that would do a swipe on all the pages currently in use. > In the SELinux policyDB, for example, one doesn't really want to > individually protect each allocation. > > The loading phase happens usually at boot, when the system can be assumed to > be sane (one might even preload a bare-bone set of rules from initramfs and > then replace it later on, with the full blown set). > > There is no need to process each of these tens of thousands allocations and > initialization as write-rare. > > Would it be possible to do the same here? What Andy is proposing effectively puts all rare allocations into one pool. Although I suppose it could be generalised to multiple pools ... one mm_struct per pool. Andy, what do you think to doing that? > > but we'd probably wrap it in list_for_each_rare_entry(), just to be nicer. > > This seems suspiciously close to the duplication of kernel interfaces that I > was roasted for :-) Can you not see the difference between adding one syntactic sugar function and duplicating the entire infrastructure?