From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756797AbcFAADp (ORCPT ); Tue, 31 May 2016 20:03:45 -0400 Received: from mail-bl2on0120.outbound.protection.outlook.com ([65.55.169.120]:13408 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750884AbcFAADn (ORCPT ); Tue, 31 May 2016 20:03:43 -0400 X-Greylist: delayed 1051 seconds by postgrey-1.27 at vger.kernel.org; Tue, 31 May 2016 20:03:43 EDT From: "Kani, Toshimitsu" To: "mcgrof@kernel.org" CC: "toshi.kani@hp.com" , "linux-kernel@vger.kernel.org" , "hch@infradead.org" , "dan.j.williams@intel.com" , "x86@kernel.org" , "paulmck@linux.vnet.ibm.com" , "will.deacon@arm.com" , "bp@alien8.de" , "julia.lawall@lip6.fr" , "linux-arch@vger.kernel.org" , "benh@kernel.crashing.org" Subject: Re: Enhancing semantics with memremap() - aliasing with memremap() Thread-Topic: Enhancing semantics with memremap() - aliasing with memremap() Thread-Index: AQHRthVDho+zNd3120yI7X/UTyAh7J/TTyMAgAAHewCAAACEgIAAYywA Date: Tue, 31 May 2016 23:31:54 +0000 Message-ID: <1464736922.3504.85.camel@hpe.com> References: <20160531165828.GA25366@infradead.org> <20160531172514.GI11948@wotan.suse.de> <20160531172705.GJ11948@wotan.suse.de> In-Reply-To: <20160531172705.GJ11948@wotan.suse.de> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: kernel.org; dkim=none (message not signed) header.d=none;kernel.org; dmarc=none action=none header.from=hpe.com; x-originating-ip: [15.219.163.9] x-ms-office365-filtering-correlation-id: 6fc4b6f0-9d75-4157-8a7b-08d389abbffa x-microsoft-exchange-diagnostics: 1;CS1PR84MB0008;5:DN58zIv8m4mVCco/944DkbD8lY2TXwbQeOnBCWCF5of7VBwW60nNnUc9w0EtHZOxVKXwZV30qrJapv6V2r3dORxtfH/SNnZIeszAW6u+6+xUX1EFTDzcqnsxCCZqvUwbSlqnBXZKZb0eioL6+d6Yvw==;24:OiHNqOJEVscOsoo3/qLOcZYhTAGuk3NIbokpqHGVHPwx7C5+oQ/6Fcnmpz8aSMy6s6W+zE3dSiI1QKYa42vkeuCQy0l79lUYawWDhYMX608=;7:LuVqkCoYQKoZTRn31hyyTIelgqivpfqNUuygyRQ8Z4m1LQXe1ynZj3MugT4uoAlRjXD3MKHk5UeZM+I0X8GRUcl8CzznP7pK30WVkC+SDmzXq4HcBrcChp7o5hEyEQdPqjJ9Wh7dBe6cY5lwBola5YB1KSSeOPNcuO3KrVpfox1mepRmBO/YxvFRKqudkreo x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:CS1PR84MB0008; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:; x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(601004)(2401047)(8121501046)(5005006)(3002001)(10201501046);SRVR:CS1PR84MB0008;BCL:0;PCL:0;RULEID:;SRVR:CS1PR84MB0008; x-forefront-prvs: 095972DF2F x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(6009001)(377424004)(24454002)(11100500001)(77096005)(87936001)(106116001)(110136002)(93886004)(92566002)(8666004)(5002640100001)(5008740100001)(2501003)(5640700001)(2906002)(3660700001)(33646002)(3280700002)(76176999)(103116003)(50986999)(54356999)(2351001)(2900100001)(586003)(36756003)(2950100001)(4326007)(6116002)(102836003)(66066001)(3846002)(86362001)(99286002)(189998001)(122556002)(5004730100002)(8936002)(1730700003)(8676002)(81166006)(7059030);DIR:OUT;SFP:1102;SCL:1;SRVR:CS1PR84MB0008;H:CS1PR84MB0005.NAMPRD84.PROD.OUTLOOK.COM;FPR:;SPF:None;MLV:sfv;LANG:en; spamdiagnosticoutput: 1:23 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="utf-8" Content-ID: <73FAE9D6A5530548A204EB6AD2ADD190@NAMPRD84.PROD.OUTLOOK.COM> MIME-Version: 1.0 X-OriginatorOrg: hpe.com X-MS-Exchange-CrossTenant-originalarrivaltime: 31 May 2016 23:31:54.1246 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 105b2061-b669-4b31-92ac-24d304d195dc X-MS-Exchange-Transport-CrossTenantHeadersStamped: CS1PR84MB0008 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id u5103obs006121 On Tue, 2016-05-31 at 19:27 +0200, Luis R. Rodriguez wrote: > On Tue, May 31, 2016 at 07:25:14PM +0200, Luis R. Rodriguez wrote: > > > > On Tue, May 31, 2016 at 09:58:28AM -0700, Christoph Hellwig wrote: > > > > > > On Tue, May 24, 2016 at 04:36:42PM -0700, Luis R. Rodriguez wrote: > > > > > > > > Is it a good time for that now? I would hope identifying proper > > > > aliasing uses for memremap() might be a bit easier now than for > > > > ioremap() given its not used as widely. It may be an easier target > > > > to also write some grammar rules for it as well. > > >  > > > So you want an explicit opt-in flag to allow aliasing?  Sounds fine to > > > me. > >    > > Yup! Can the default then safely already be no-aliasing then? > > Or if aliasing is truly not needed as often a different API, this > maybe useful later if we pick up again module namespace stuff. I agree that we should be able to change memremap() to fail an aliasing request since it's a relatively new interface.  ioremap() needs to start from adding a warning message. Thanks, -Toshi