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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 D9F90C43603 for ; Thu, 19 Dec 2019 12:04:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B11C7222C2 for ; Thu, 19 Dec 2019 12:04:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576757060; bh=HgXtsgN6xVx39MU4q6JvdB/g0TZMwtT2d6vaIKJJ5e4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=qd48ACvoWQelxQte9u8IiUgxjrba6dkraLwCyC8Pv/pPz3avUaIFVkxYPvUD/KRhc gsdGvgrnK+gtKRDQJNgD7yzVb06aeTpksMwDpzV8qE1nNvCSIRAUmzjV/EfRER1Vwt dXui1oFyqajWHYI/zv2RY4Nnq2lypfuM/UTmAq7w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727052AbfLSMET (ORCPT ); Thu, 19 Dec 2019 07:04:19 -0500 Received: from mail.kernel.org ([198.145.29.99]:36106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726960AbfLSMEQ (ORCPT ); Thu, 19 Dec 2019 07:04:16 -0500 Received: from localhost.localdomain (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 38F3924650; Thu, 19 Dec 2019 12:04:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576757055; bh=HgXtsgN6xVx39MU4q6JvdB/g0TZMwtT2d6vaIKJJ5e4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fSl4t6pZfzElFVqBe6knTYDJ8hQQJN06DOMfiZ24+Lj+iTbPaX1gp9MPVlH7hrgLL QxOTiYz0yX822cb2EDGpEGHb2EjvtqqC2fwNoo7s6LAf4BBGLKG7LRICMjP+cI0wqx cEgub9F/yFmYnjQzP3EyF2lf5wvt8KPKsLhOfcCk= From: Will Deacon To: linux-kernel@vger.kernel.org, iommu@lists.linuxfoundation.org Cc: kernel-team@android.com, Will Deacon , Jean-Philippe Brucker , Jordan Crouse , John Garry , Bjorn Helgaas , Saravana Kannan , Greg Kroah-Hartman , "Isaac J. Manjarres" , Robin Murphy , Lorenzo Pieralisi , Joerg Roedel , Ard Biesheuvel Subject: [PATCH v4 05/16] drivers/iommu: Take a ref to the IOMMU driver prior to ->add_device() Date: Thu, 19 Dec 2019 12:03:41 +0000 Message-Id: <20191219120352.382-6-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191219120352.382-1-will@kernel.org> References: <20191219120352.382-1-will@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org To avoid accidental removal of an active IOMMU driver module, take a reference to the driver module in 'iommu_probe_device()' immediately prior to invoking the '->add_device()' callback and hold it until the after the device has been removed by '->remove_device()'. Suggested-by: Joerg Roedel Signed-off-by: Will Deacon --- drivers/iommu/iommu.c | 19 +++++++++++++++++-- include/linux/iommu.h | 4 +++- 2 files changed, 20 insertions(+), 3 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 7c92197d53f3..bc8edf90e729 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -22,6 +22,7 @@ #include #include #include +#include #include static struct kset *iommu_group_kset; @@ -185,10 +186,21 @@ int iommu_probe_device(struct device *dev) if (!iommu_get_dev_param(dev)) return -ENOMEM; + if (!try_module_get(ops->owner)) { + ret = -EINVAL; + goto err_free_dev_param; + } + ret = ops->add_device(dev); if (ret) - iommu_free_dev_param(dev); + goto err_module_put; + + return 0; +err_module_put: + module_put(ops->owner); +err_free_dev_param: + iommu_free_dev_param(dev); return ret; } @@ -199,7 +211,10 @@ void iommu_release_device(struct device *dev) if (dev->iommu_group) ops->remove_device(dev); - iommu_free_dev_param(dev); + if (dev->iommu_param) { + module_put(ops->owner); + iommu_free_dev_param(dev); + } } static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus, diff --git a/include/linux/iommu.h b/include/linux/iommu.h index f2223cbb5fd5..e9f94d3f7a04 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -246,9 +246,10 @@ struct iommu_iotlb_gather { * @sva_get_pasid: Get PASID associated to a SVA handle * @page_response: handle page request response * @cache_invalidate: invalidate translation caches - * @pgsize_bitmap: bitmap of all possible supported page sizes * @sva_bind_gpasid: bind guest pasid and mm * @sva_unbind_gpasid: unbind guest pasid and mm + * @pgsize_bitmap: bitmap of all possible supported page sizes + * @owner: Driver module providing these ops */ struct iommu_ops { bool (*capable)(enum iommu_cap); @@ -318,6 +319,7 @@ struct iommu_ops { int (*sva_unbind_gpasid)(struct device *dev, int pasid); unsigned long pgsize_bitmap; + struct module *owner; }; /** -- 2.24.1.735.g03f4e72817-goog