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=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,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 35406C433B4 for ; Sun, 2 May 2021 19:58:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 989CD61221 for ; Sun, 2 May 2021 19:58:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 989CD61221 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 271F16B0036; Sun, 2 May 2021 15:58:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 221A86B006E; Sun, 2 May 2021 15:58:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 04D1F6B0070; Sun, 2 May 2021 15:58:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0097.hostedemail.com [216.40.44.97]) by kanga.kvack.org (Postfix) with ESMTP id DDA2B6B0036 for ; Sun, 2 May 2021 15:58:42 -0400 (EDT) Received: from smtpin09.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 76400181AEF3E for ; Sun, 2 May 2021 19:58:42 +0000 (UTC) X-FDA: 78097353684.09.2C08CC7 Received: from NAM02-BL2-obe.outbound.protection.outlook.com (mail-eopbgr750073.outbound.protection.outlook.com [40.107.75.73]) by imf02.hostedemail.com (Postfix) with ESMTP id 88C0640002DA for ; Sun, 2 May 2021 19:58:10 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=R/cnupS7bk6IcjeR66fkwxA6gPy+fmjpnO8ureHYwn83Zo8PLaE7bNbV2MJB8bODKI/hbMBqptyDTacy1ZKDCL+SXs1ncE6TIKL30CUl2Ealkaj3mXjvsaHPWO2LoPjnVW8MH3LWnLIrMSBrJ/SxTWK17U1IMZvGfCOLPn+sm/Xkjbn72nObwOH+/7diiyTpp5QSTFXFM1QDb+D/5f6SLcFU8/P2x/3CmDRVpJHQSiaX0wIIdLUgD/XNJYF4Fy997eCS64EzvftDVs7bt68/9smQqGL78qRy5+jcFMT4eXTK7KDk7uVCYZreI0oGLKSvZTRJYqLvrGFd1TFHKPoqaw== 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=5nOyp69OoyQYNuJI/+RFuZqsBro/iudgEZwMU8Sb9n8=; b=XRTGJW5GDGehWa7l8RKWDOxbVBoVK8xScNSg/tyhFd5Bb0uPiLNGZaLT22qhyitTvhKDMuhqug01h2zaMP7snvQNol8ULY4CdJFbEo4ckQbbyf/yuI+KJqnVlPv2daWjaG6z7q3fwg5UYr889vKuIh2vxsxK8EsEWo9gcejXKEyATZeBt00MTYhXMr8uDgitiieiUp9nnCRKfki2gaF73JGN7DlRDNYpqQbfUv/FQwaeuBgO5RCsMSaAxTX+/XevW2MZA36XKY63av9QrKI/6PhTIkT09zh2I3ETiq2IsxBKPuKZxctwoBKhvmlxIXNw28CZNn1R6h2aWV+qCyaUfQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 216.228.112.34) smtp.rcpttodomain=raithlin.com smtp.mailfrom=nvidia.com; dmarc=pass (p=none sp=none pct=100) action=none header.from=nvidia.com; dkim=none (message not signed); arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=5nOyp69OoyQYNuJI/+RFuZqsBro/iudgEZwMU8Sb9n8=; b=i27KtrfiNwNMgd4eGd2eq7hcxl69xb2OPU10VFeL2u41b9oFsXx7TWQvgwEZZbBOvl5x+Wxx+K48FTC0MmVNTj4l0dNylaqEj1cDQurEcTkpRZaJsQjs1Fa2xiBrlHrhr3z0X+GkjjbRYe/kun6qNjJ9DvpbElVAXf9CsXjogaAj/z79YEORR9Hn24AX755as69BtavD3mc4qxqFyX1qZ2KXxeq86a+f4tJ4+afySXdcvrdkGqJXP3ArK0SdVfPgWyIZDTA6KKmPusvry1YvL5GZ6KnFJEHxVBYs8c0lrOcHPdpppphvl/Aut85F51DKhGxC1DnAuvDpX4z9CfGDHQ== Received: from MW4PR04CA0308.namprd04.prod.outlook.com (2603:10b6:303:82::13) by DM6PR12MB4563.namprd12.prod.outlook.com (2603:10b6:5:28e::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4087.25; Sun, 2 May 2021 19:58:40 +0000 Received: from CO1NAM11FT047.eop-nam11.prod.protection.outlook.com (2603:10b6:303:82:cafe::e6) by MW4PR04CA0308.outlook.office365.com (2603:10b6:303:82::13) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4087.27 via Frontend Transport; Sun, 2 May 2021 19:58:40 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 216.228.112.34) smtp.mailfrom=nvidia.com; raithlin.com; dkim=none (message not signed) header.d=none;raithlin.com; dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 216.228.112.34 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.112.34; helo=mail.nvidia.com; Received: from mail.nvidia.com (216.228.112.34) by CO1NAM11FT047.mail.protection.outlook.com (10.13.174.132) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.20.4087.27 via Frontend Transport; Sun, 2 May 2021 19:58:39 +0000 Received: from [10.2.50.162] (172.20.145.6) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sun, 2 May 2021 19:58:38 +0000 Subject: Re: [PATCH 03/16] PCI/P2PDMA: Attempt to set map_type if it has not been set To: Logan Gunthorpe , , , , , , CC: Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , =?UTF-8?Q?Christian_K=c3=b6nig?= , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy References: <20210408170123.8788-1-logang@deltatee.com> <20210408170123.8788-4-logang@deltatee.com> From: John Hubbard Message-ID: <3834be62-3d1b-fc98-d793-e7dcb0a74624@nvidia.com> Date: Sun, 2 May 2021 12:58:38 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: <20210408170123.8788-4-logang@deltatee.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [172.20.145.6] X-ClientProxiedBy: HQMAIL105.nvidia.com (172.20.187.12) To HQMAIL107.nvidia.com (172.20.187.13) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 5b43cf32-e796-4b45-ab8f-08d90da4ae2c X-MS-TrafficTypeDiagnostic: DM6PR12MB4563: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:8273; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:216.228.112.34;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:mail.nvidia.com;PTR:schybrid03.nvidia.com;CAT:NONE;SFS:(4636009)(376002)(396003)(136003)(346002)(39860400002)(36840700001)(46966006)(110136005)(86362001)(2616005)(356005)(7416002)(82740400003)(8676002)(26005)(31686004)(36860700001)(70206006)(5660300002)(7636003)(478600001)(53546011)(8936002)(316002)(82310400003)(186003)(83380400001)(54906003)(426003)(4326008)(70586007)(16526019)(2906002)(336012)(16576012)(36906005)(47076005)(31696002)(36756003)(43740500002)(2101003);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 May 2021 19:58:39.6557 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 5b43cf32-e796-4b45-ab8f-08d90da4ae2c X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.112.34];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: CO1NAM11FT047.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM6PR12MB4563 Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b=i27Ktrfi; spf=none (imf02.hostedemail.com: domain of jhubbard@nvidia.com has no SPF policy when checking 40.107.75.73) smtp.mailfrom=jhubbard@nvidia.com; dmarc=pass (policy=none) header.from=nvidia.com X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 88C0640002DA X-Stat-Signature: gywyfgz9ystph9izgijadk43st8hbazq Received-SPF: none (nvidia.com>: No applicable sender policy available) receiver=imf02; identity=mailfrom; envelope-from=""; helo=NAM02-BL2-obe.outbound.protection.outlook.com; client-ip=40.107.75.73 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1619985490-442772 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 4/8/21 10:01 AM, Logan Gunthorpe wrote: > Attempt to find the mapping type for P2PDMA pages on the first > DMA map attempt if it has not been done ahead of time. > > Previously, the mapping type was expected to be calculated ahead of > time, but if pages are to come from userspace then there's no > way to ensure the path was checked ahead of time. > > Signed-off-by: Logan Gunthorpe > --- > drivers/pci/p2pdma.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index 473a08940fbc..2574a062a255 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -825,11 +825,18 @@ EXPORT_SYMBOL_GPL(pci_p2pmem_publish); > static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct pci_dev *provider, > struct pci_dev *client) > { > + enum pci_p2pdma_map_type ret; > + > if (!provider->p2pdma) > return PCI_P2PDMA_MAP_NOT_SUPPORTED; > > - return xa_to_value(xa_load(&provider->p2pdma->map_types, > - map_types_idx(client))); > + ret = xa_to_value(xa_load(&provider->p2pdma->map_types, > + map_types_idx(client))); > + if (ret != PCI_P2PDMA_MAP_UNKNOWN) > + return ret; > + > + return upstream_bridge_distance_warn(provider, client, NULL, > + GFP_ATOMIC); Returning a "bridge distance" from a "get map type" routine is jarring, and I think it is because of a pre-existing problem: the above function is severely misnamed. Let's try renaming it (and the other one) to approximately: upstream_bridge_map_type_warn() upstream_bridge_map_type() ...and that should fix that. Well, that, plus tweaking the kernel doc comments, which are also confused. I think someone started off thinking about distances through PCIe, but in the end, the routine boils down to just a few situations that are not distances at all. Also, the above will read a little better if it is written like this: ret = xa_to_value(xa_load(&provider->p2pdma->map_types, map_types_idx(client))); if (ret == PCI_P2PDMA_MAP_UNKNOWN) ret = upstream_bridge_map_type_warn(provider, client, NULL, GFP_ATOMIC); return ret; > } > > static int __pci_p2pdma_map_sg(struct pci_p2pdma_pagemap *p2p_pgmap, > @@ -877,7 +884,6 @@ int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, > case PCI_P2PDMA_MAP_BUS_ADDR: > return __pci_p2pdma_map_sg(p2p_pgmap, dev, sg, nents); > default: > - WARN_ON_ONCE(1); Why? Or at least, why, in this patch? It looks like an accidental leftover from something, seeing as how it is not directly related to the patch, and is not mentioned at all. thanks, -- John Hubbard NVIDIA > return 0; > } > } >