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=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 4B5A1C64E7A for ; Tue, 24 Nov 2020 12:58:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0648F2073C for ; Tue, 24 Nov 2020 12:58:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=nvidia.com header.i=@nvidia.com header.b="Pp/o8HZa" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387660AbgKXM62 (ORCPT ); Tue, 24 Nov 2020 07:58:28 -0500 Received: from nat-hk.nvidia.com ([203.18.50.4]:17722 "EHLO nat-hk.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387752AbgKXM62 (ORCPT ); Tue, 24 Nov 2020 07:58:28 -0500 Received: from HKMAIL104.nvidia.com (Not Verified[10.18.92.9]) by nat-hk.nvidia.com (using TLS: TLSv1.2, AES256-SHA) id ; Tue, 24 Nov 2020 20:58:27 +0800 Received: from HKMAIL103.nvidia.com (10.18.16.12) by HKMAIL104.nvidia.com (10.18.16.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Tue, 24 Nov 2020 12:58:26 +0000 Received: from NAM11-BN8-obe.outbound.protection.outlook.com (104.47.58.174) by HKMAIL103.nvidia.com (10.18.16.12) with Microsoft SMTP Server (TLS) id 15.0.1473.3 via Frontend Transport; Tue, 24 Nov 2020 12:58:26 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=WgGNqV5sELR6CfL2pTRhXI01026A4w9Ki0nLWmXeLYGOS+wLC7K29GKLUkVZFPYKLQNEGwuZIxaRC1oibArVK5FxgudtS4MHKjRkdHFk0D03ZVMdamvmMrWgenNIS9Q9it5k5yv4gCwYf9XWJgAPZOjBwtHuHM6B5aEwk1nRMVUrVt2pFfwAmZ4H0eaSOCxsoArfIuCS6/+upgtN3jnaCqwp8pwCvN2bv32HoSEQQvqAacGuTp6NPEAy7yIxAD4BsNXYI6R63of2V1T+fTetyGHbjHJ7sxQidsgKGjJjXjDhFQnSS1eRtkcHdOerAOqFrj5urKbPCmONPwRE6VCg/A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=GeWPscVr8LMmvlT5GuDD2T7j3+wG9XhGa77WtojiPp0=; b=aLMQ+2pVLCDmGGj1LuXj3jktW+UYUnFoFJanTPsfHXRmqXhYCcdQBVZ0Xev7CSkrdEhx1Vk2OG9XQaMKHyVWHIFUD+7VeQtaW48WX/Btc7LWElbVx9ugN829X8+Bl56tuR1SbEst4Bdm6bhad6iR6Zk99/OQL+L7ch2fq4LggBXUPwLFUgdc3Qh/nmUvEPMuj5WUqIdfB2nNCdrkK9ozSz+BX81KA3vPmvdiFYR/HQ/AmEGjJC6YUK/Qx4LnVGDm24n48hhvmPjkikh+FWvxIRUpr2JwOgvZSYWxorHFnGkf1fXJ8SBVH5nQ6WkqC+ho5lQwXEl8nBJprt3fHOj2JA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none Received: from DM6PR12MB3834.namprd12.prod.outlook.com (2603:10b6:5:14a::12) by DM6PR12MB4057.namprd12.prod.outlook.com (2603:10b6:5:213::9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3589.20; Tue, 24 Nov 2020 12:58:24 +0000 Received: from DM6PR12MB3834.namprd12.prod.outlook.com ([fe80::e40c:730c:156c:2ef9]) by DM6PR12MB3834.namprd12.prod.outlook.com ([fe80::e40c:730c:156c:2ef9%7]) with mapi id 15.20.3589.022; Tue, 24 Nov 2020 12:58:24 +0000 Date: Tue, 24 Nov 2020 08:58:22 -0400 From: Jason Gunthorpe To: Leon Romanovsky CC: Parav Pandit , Doug Ledford , "linux-rdma@vger.kernel.org" Subject: Re: [PATCH rdma-next] IB/mlx5: Use ib_dma APIs instead of open access to parent device Message-ID: <20201124125822.GA4800@nvidia.com> References: <20201123082400.351371-1-leon@kernel.org> <20201123135931.GM917484@nvidia.com> <20201124052032.GE3159@unreal> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20201124052032.GE3159@unreal> X-ClientProxiedBy: MN2PR03CA0025.namprd03.prod.outlook.com (2603:10b6:208:23a::30) To DM6PR12MB3834.namprd12.prod.outlook.com (2603:10b6:5:14a::12) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from mlx.ziepe.ca (156.34.48.30) by MN2PR03CA0025.namprd03.prod.outlook.com (2603:10b6:208:23a::30) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3611.20 via Frontend Transport; Tue, 24 Nov 2020 12:58:24 +0000 Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1khXtm-000jlS-TK; Tue, 24 Nov 2020 08:58:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1606222707; bh=GeWPscVr8LMmvlT5GuDD2T7j3+wG9XhGa77WtojiPp0=; h=ARC-Seal:ARC-Message-Signature:ARC-Authentication-Results:Date: From:To:CC:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:X-ClientProxiedBy:MIME-Version: X-MS-Exchange-MessageSentRepresentingType; b=Pp/o8HZaj/IDu0KZHKNSH0Dl45/ugQCIiFPBdAdq/AvpFFsq0ESbRADSJuTC9oDiS 8j+5gf2WJfkZe6eYLA9UpSLEEVk7CsF+yWC9so7DRJjecLgw6QDeri+v4/uS/Kmz5j 3wihNGZMg7Cz0aOCZfm9O+ws25F1lyyQqRHVpMtMeUlzd2XXsXSxrbXytXDe7pjlI+ qS68OdoLQMglueINImmPnCPRVOoVOqS+hpyv7gRjBxc5qfdva2dooWEy28qojIP3d6 48s+eFZWrAPtfU32hxsicyWkHYjIxC/O4k1jh0V0MB9Kam+PpRWixUe/Nhe2Bk7eWN BeKCTeN1Y4B3g== Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Tue, Nov 24, 2020 at 07:20:32AM +0200, Leon Romanovsky wrote: > On Tue, Nov 24, 2020 at 03:34:56AM +0000, Parav Pandit wrote: > > > > > > > From: Jason Gunthorpe > > > Sent: Monday, November 23, 2020 7:30 PM > > > > > > On Mon, Nov 23, 2020 at 10:24:00AM +0200, Leon Romanovsky wrote: > > > > From: Parav Pandit > > > > > > > > DMA operation of the IB device is done using ib_device->dma_device. > > > > This is well abstracted using ib_dma APIs. > > > > > > > > Hence, instead of doing open access to parent device, use IB core > > > > provided dma mapping APIs. > > > > > > Why? > > > > > > The ib DMA APIs are for people using verbs, they are only needed to pack things > > > into the ib_sge > > > > > > If you are inside a driver, not using the verbs API, or not using ib_sge, then you > > > should not be using the ib_dma API > > > > > Thanks for clarifying this. Using ib_dma apis make the code clear for dma device access clear and explicit. > > > > > It is an abberation, we should minimize its use. > > Alright. In that case will use the pci_dev as mlx5 driver internally has the knowledge of it and avoid using ib_dma APIs. > > Yeah, let's do v2, although I don't understand the purpose of ib_dma > helpers if ib drivers can't use it. They are for ULPs, not drivers. Drivers are supposed to know how they are doing dma mapping already Jason