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=ham 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 149CEC5DF60 for ; Fri, 8 Nov 2019 15:16:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CF072222D4 for ; Fri, 8 Nov 2019 15:16:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573226188; bh=Jt4zDx9Zw6bm/De+bvs+7nLVRvQ+umN66VOrNXeB3lw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pLGKwmszfZk8x53qK1vaxNhh/bPfp+pN+vvDaZj1zu0im41bRRV+GQKaVCPqUlSlT rWaJRevyJ0iAVwq68kTrS6VMK5nQ0E2Vmp+Aesa5s5SykNFv18SuXGpei0ygI6/Q5L /ybRendxPJSdNiz36pDgWTCCT2ROzXQMgpExNqak= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727351AbfKHPQ1 (ORCPT ); Fri, 8 Nov 2019 10:16:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:36070 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726095AbfKHPQ0 (ORCPT ); Fri, 8 Nov 2019 10:16:26 -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 A4612222C9; Fri, 8 Nov 2019 15:16:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573226185; bh=Jt4zDx9Zw6bm/De+bvs+7nLVRvQ+umN66VOrNXeB3lw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u45KmJF+a/PqKLMwTdUXriHt1lGZ3Sqkymh5MXx5NRKiWZ7jGRcMB2fRNoMKOT6M2 2Z/M5bq5aQ74aqn1pYWzRDzTLX3aUfwgxjZD1UpdzQeWTwZzcKjh79oKboEYerQA4Q oKr26vXNfJp9uJz6cIoAPODvNwB111nZTl+vxVTo= From: Will Deacon To: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Cc: Will Deacon , Jean-Philippe Brucker , Jordan Crouse , John Garry , Bjorn Helgaas , Saravana Kannan , "Isaac J. Manjarres" , Robin Murphy , Lorenzo Pieralisi , Joerg Roedel Subject: [PATCH v2 4/9] drivers/iommu: Take a ref to the IOMMU driver prior to ->add_device() Date: Fri, 8 Nov 2019 15:16:03 +0000 Message-Id: <20191108151608.20932-5-will@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191108151608.20932-1-will@kernel.org> References: <20191108151608.20932-1-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 | 2 ++ 2 files changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index c1aadb570145..4bfecfbbe2cf 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 29bac5345563..d9dab5a3e912 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -245,6 +245,7 @@ struct iommu_iotlb_gather { * @sva_get_pasid: Get PASID associated to a SVA handle * @page_response: handle page request response * @pgsize_bitmap: bitmap of all possible supported page sizes + * @owner: Driver module providing these ops */ struct iommu_ops { bool (*capable)(enum iommu_cap); @@ -308,6 +309,7 @@ struct iommu_ops { struct iommu_page_response *msg); unsigned long pgsize_bitmap; + struct module *owner; }; /** -- 2.24.0.rc1.363.gb1bccd3e3d-goog