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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 C611EC433E6 for ; Fri, 12 Mar 2021 11:26:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8911564FC3 for ; Fri, 12 Mar 2021 11:26:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233712AbhCLLZ3 (ORCPT ); Fri, 12 Mar 2021 06:25:29 -0500 Received: from mx2.suse.de ([195.135.220.15]:44122 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233730AbhCLLZ2 (ORCPT ); Fri, 12 Mar 2021 06:25:28 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 03CE7B03C; Fri, 12 Mar 2021 11:25:27 +0000 (UTC) Received: by ds.suse.cz (Postfix, from userid 10065) id 388D2DA81D; Fri, 12 Mar 2021 12:23:27 +0100 (CET) Date: Fri, 12 Mar 2021 12:23:27 +0100 From: David Sterba To: ira.weiny@intel.com Cc: Andrew Morton , David Sterba , Chris Mason , Josef Bacik , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] btrfs: Use memzero_page() instead of open coded kmap pattern Message-ID: <20210312112327.GP7604@suse.cz> Reply-To: dsterba@suse.cz Mail-Followup-To: dsterba@suse.cz, ira.weiny@intel.com, Andrew Morton , David Sterba , Chris Mason , Josef Bacik , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210309212137.2610186-1-ira.weiny@intel.com> <20210309212137.2610186-4-ira.weiny@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210309212137.2610186-4-ira.weiny@intel.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Mar 09, 2021 at 01:21:37PM -0800, ira.weiny@intel.com wrote: > From: Ira Weiny > > There are many places where kmap/memset/kunmap patterns occur. > > Use the newly lifted memzero_page() to eliminate direct uses of kmap and > leverage the new core functions use of kmap_local_page(). > > The development of this patch was aided by the following coccinelle > script: > > // > // SPDX-License-Identifier: GPL-2.0-only > // Find kmap/memset/kunmap pattern and replace with memset*page calls > // > // NOTE: Offsets and other expressions may be more complex than what the script > // will automatically generate. Therefore a catchall rule is provided to find > // the pattern which then must be evaluated by hand. > // > // Confidence: Low > // Copyright: (C) 2021 Intel Corporation > // URL: http://coccinelle.lip6.fr/ > // Comments: > // Options: > > // > // Then the memset pattern > // > @ memset_rule1 @ > expression page, V, L, Off; > identifier ptr; > type VP; > @@ > > ( > -VP ptr = kmap(page); > | > -ptr = kmap(page); > | > -VP ptr = kmap_atomic(page); > | > -ptr = kmap_atomic(page); > ) > <+... > ( > -memset(ptr, 0, L); > +memzero_page(page, 0, L); > | > -memset(ptr + Off, 0, L); > +memzero_page(page, Off, L); > | > -memset(ptr, V, L); > +memset_page(page, V, 0, L); > | > -memset(ptr + Off, V, L); > +memset_page(page, V, Off, L); > ) > ...+> > ( > -kunmap(page); > | > -kunmap_atomic(ptr); > ) > > // Remove any pointers left unused > @ > depends on memset_rule1 > @ > identifier memset_rule1.ptr; > type VP, VP1; > @@ > > -VP ptr; > ... when != ptr; > ? VP1 ptr; > > // > // Catch all > // > @ memset_rule2 @ > expression page; > identifier ptr; > expression GenTo, GenSize, GenValue; > type VP; > @@ > > ( > -VP ptr = kmap(page); > | > -ptr = kmap(page); > | > -VP ptr = kmap_atomic(page); > | > -ptr = kmap_atomic(page); > ) > <+... > ( > // > // Some call sites have complex expressions within the memset/memcpy > // The follow are catch alls which need to be evaluated by hand. > // > -memset(GenTo, 0, GenSize); > +memzero_pageExtra(page, GenTo, GenSize); > | > -memset(GenTo, GenValue, GenSize); > +memset_pageExtra(page, GenValue, GenTo, GenSize); > ) > ...+> > ( > -kunmap(page); > | > -kunmap_atomic(ptr); > ) > > // Remove any pointers left unused > @ > depends on memset_rule2 > @ > identifier memset_rule2.ptr; > type VP, VP1; > @@ > > -VP ptr; > ... when != ptr; > ? VP1 ptr; > > // > > Signed-off-by: Ira Weiny Reviewed-by: David Sterba