From patchwork Wed Oct 27 09:56:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yishai Hadas X-Patchwork-Id: 12586899 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 300C0C433EF for ; Wed, 27 Oct 2021 09:58:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D53F610A0 for ; Wed, 27 Oct 2021 09:58:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241304AbhJ0KAg (ORCPT ); Wed, 27 Oct 2021 06:00:36 -0400 Received: from mail-dm6nam10on2070.outbound.protection.outlook.com ([40.107.93.70]:1761 "EHLO NAM10-DM6-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S237126AbhJ0KAc (ORCPT ); Wed, 27 Oct 2021 06:00:32 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=KsZSGP4K+3GrWz8SfcXHGPMwIaheA2eYTNbtNmNw1Uce1iCQaklkXZBOiol2iixSBFaFAK3Qtbo+F6kU/EFuzTCuS6fIx9jDGmPtszCP/un6IXuoeGoLgsh+H/eeIYnBUXsEMouQoarCzFb+3gW8gRme8jB3VOI41o3N9o7iFp6sf04qIJEO5YUZXOLqQZwI8YB4xWAObq9ezShgQnrta+FkvdWIm5g63E2C6vrj7mUNryH48w+D/D1HLEm9199LhVzoO5QvDTkWkMVUMk6qpjuZIv1ZtSW9AMlB06jWCLvizLrn8PAVNHVvhh8eeUgtkMcSs9ySsz3KYdDWgkzcBA== 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-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=PX8vNibUQ+77tQfzz+YEsNNh/fZeI9f68zyWZiZWxw8=; b=aCsjrCEoA9BYlQaqZbZ2Ua+7srm5X47JDNcLRA1MmQ6/jBPa1SqUGkK91BARhUGXt6knc3DUAbkon7LYCCLJet8TmMSonr2dEfrvFzsl6DAVamMz84sgutP3ydaZkGHR87Uf6cRivWhinxaBKutNHaNVfZn9L8uT8juhBei3n27Q8d0RWurcWsOwDbQZpn2pg0Hg7YWIIF9ySXDcxJCdaenybLumvE1SdJsdQcOPQfkI8ZMyAZ43TI2r12AgY5bSbsmFV5XxE8sizXNphEMmZAqt0BIfWNs1L96NHBqR1F8wiJTY4/NbaTj3avf+Ms0nU4TSgR49YIJpXTF9bQH2DQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass (sender ip is 216.228.112.34) smtp.rcpttodomain=vger.kernel.org smtp.mailfrom=nvidia.com; dmarc=pass (p=quarantine sp=quarantine 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=PX8vNibUQ+77tQfzz+YEsNNh/fZeI9f68zyWZiZWxw8=; b=cQmGflL3BQI7IT2EwBZGDGjF0GCRL+37ScZkcAGzdIWkradbKIKIFY8B5E/bvWOmCMdNOYZs15sVnODIFeJ3hSjGdTdkEP0b+pzztzAqenJxhFy6GIdzard8MoAbAE3b4XS5yAskw1XYiT4Bec8XHlLzeKShYAIaXiorfV8fW2nWmzsDoXduedCftbYNE8QJ4+Zz6m+eBV7YqxhBCj7UqfmbFjGzCOGzBkHBJzKb82ptuk5Epgnq5vWERJP7TfvxMyY1HjdwrJ2GDjAfibQTNeCPTK1g6EEi/Kenbe7kDwnJBHtQ3we9avRi0q5fuHwksIqWRxRV10UYTc24WSrpGQ== Received: from DM6PR11CA0051.namprd11.prod.outlook.com (2603:10b6:5:14c::28) by PH0PR12MB5497.namprd12.prod.outlook.com (2603:10b6:510:eb::22) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4628.18; Wed, 27 Oct 2021 09:58:05 +0000 Received: from DM6NAM11FT044.eop-nam11.prod.protection.outlook.com (2603:10b6:5:14c:cafe::6c) by DM6PR11CA0051.outlook.office365.com (2603:10b6:5:14c::28) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4649.14 via Frontend Transport; Wed, 27 Oct 2021 09:58:05 +0000 X-MS-Exchange-Authentication-Results: spf=pass (sender IP is 216.228.112.34) smtp.mailfrom=nvidia.com; vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; 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 DM6NAM11FT044.mail.protection.outlook.com (10.13.173.185) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.20.4649.14 via Frontend Transport; Wed, 27 Oct 2021 09:58:05 +0000 Received: from HQMAIL111.nvidia.com (172.20.187.18) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1497.18; Wed, 27 Oct 2021 09:58:04 +0000 Received: from vdi.nvidia.com (172.20.187.5) by mail.nvidia.com (172.20.187.18) with Microsoft SMTP Server id 15.0.1497.18 via Frontend Transport; Wed, 27 Oct 2021 09:58:01 +0000 From: Yishai Hadas To: , , , CC: , , , , , , , , Subject: [PATCH V5 mlx5-next 04/13] PCI/IOV: Add pci_iov_get_pf_drvdata() to allow VF reaching the drvdata of a PF Date: Wed, 27 Oct 2021 12:56:49 +0300 Message-ID: <20211027095658.144468-5-yishaih@nvidia.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20211027095658.144468-1-yishaih@nvidia.com> References: <20211027095658.144468-1-yishaih@nvidia.com> MIME-Version: 1.0 X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 85387722-f879-4503-6e79-08d99930457a X-MS-TrafficTypeDiagnostic: PH0PR12MB5497: X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:7219; X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 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)(36840700001)(46966006)(86362001)(82310400003)(36756003)(36860700001)(6636002)(110136005)(70206006)(7696005)(54906003)(107886003)(83380400001)(336012)(4326008)(36906005)(186003)(26005)(47076005)(8936002)(1076003)(8676002)(5660300002)(6666004)(426003)(7636003)(356005)(508600001)(2906002)(70586007)(316002)(2616005);DIR:OUT;SFP:1101; X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Oct 2021 09:58:05.1757 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 85387722-f879-4503-6e79-08d99930457a 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: DM6NAM11FT044.eop-nam11.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR12MB5497 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Jason Gunthorpe There are some cases where a SR-IOV VF driver will need to reach into and interact with the PF driver. This requires accessing the drvdata of the PF. Provide a function pci_iov_get_pf_drvdata() to return this PF drvdata in a safe way. Normally accessing a drvdata of a foreign struct device would be done using the device_lock() to protect against device driver probe()/remove() races. However, due to the design of pci_enable_sriov() this will result in a ABBA deadlock on the device_lock as the PF's device_lock is held during PF sriov_configure() while calling pci_enable_sriov() which in turn holds the VF's device_lock while calling VF probe(), and similarly for remove. This means the VF driver can never obtain the PF's device_lock. Instead use the implicit locking created by pci_enable/disable_sriov(). A VF driver can access its PF drvdata only while its own driver is attached, and the PF driver can control access to its own drvdata based on when it calls pci_enable/disable_sriov(). To use this API the PF driver will setup the PF drvdata in the probe() function. pci_enable_sriov() is only called from sriov_configure() which cannot happen until probe() completes, ensuring no VF races with drvdata setup. For removal, the PF driver must call pci_disable_sriov() in its remove function before destroying any of the drvdata. This ensures that all VF drivers are unbound before returning, fencing concurrent access to the drvdata. The introduction of a new function to do this access makes clear the special locking scheme and the documents the requirements on the PF/VF drivers using this. Signed-off-by: Jason Gunthorpe Acked-by: Bjorn Helgaas Signed-off-by: Leon Romanovsky Signed-off-by: Yishai Hadas --- drivers/pci/iov.c | 29 +++++++++++++++++++++++++++++ include/linux/pci.h | 7 +++++++ 2 files changed, 36 insertions(+) diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c index e7751fa3fe0b..8c724bc134c7 100644 --- a/drivers/pci/iov.c +++ b/drivers/pci/iov.c @@ -47,6 +47,35 @@ int pci_iov_vf_id(struct pci_dev *dev) } EXPORT_SYMBOL_GPL(pci_iov_vf_id); +/** + * pci_iov_get_pf_drvdata - Return the drvdata of a PF + * @dev - VF pci_dev + * @pf_driver - Device driver required to own the PF + * + * This must be called from a context that ensures that a VF driver is attached. + * The value returned is invalid once the VF driver completes its remove() + * callback. + * + * Locking is achieved by the driver core. A VF driver cannot be probed until + * pci_enable_sriov() is called and pci_disable_sriov() does not return until + * all VF drivers have completed their remove(). + * + * The PF driver must call pci_disable_sriov() before it begins to destroy the + * drvdata. + */ +void *pci_iov_get_pf_drvdata(struct pci_dev *dev, struct pci_driver *pf_driver) +{ + struct pci_dev *pf_dev; + + if (!dev->is_virtfn) + return ERR_PTR(-EINVAL); + pf_dev = dev->physfn; + if (pf_dev->driver != pf_driver) + return ERR_PTR(-EINVAL); + return pci_get_drvdata(pf_dev); +} +EXPORT_SYMBOL_GPL(pci_iov_get_pf_drvdata); + /* * Per SR-IOV spec sec 3.3.10 and 3.3.11, First VF Offset and VF Stride may * change when NumVFs changes. diff --git a/include/linux/pci.h b/include/linux/pci.h index 2337512e67f0..639a0a239774 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -2154,6 +2154,7 @@ void __iomem *pci_ioremap_wc_bar(struct pci_dev *pdev, int bar); int pci_iov_virtfn_bus(struct pci_dev *dev, int id); int pci_iov_virtfn_devfn(struct pci_dev *dev, int id); int pci_iov_vf_id(struct pci_dev *dev); +void *pci_iov_get_pf_drvdata(struct pci_dev *dev, struct pci_driver *pf_driver); int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn); void pci_disable_sriov(struct pci_dev *dev); @@ -2187,6 +2188,12 @@ static inline int pci_iov_vf_id(struct pci_dev *dev) return -ENOSYS; } +static inline void *pci_iov_get_pf_drvdata(struct pci_dev *dev, + struct pci_driver *pf_driver) +{ + return ERR_PTR(-EINVAL); +} + static inline int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn) { return -ENODEV; }