From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932918AbcFGNbT (ORCPT ); Tue, 7 Jun 2016 09:31:19 -0400 Received: from foss.arm.com ([217.140.101.70]:44413 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754867AbcFGNbI (ORCPT ); Tue, 7 Jun 2016 09:31:08 -0400 From: Lorenzo Pieralisi To: iommu@lists.linux-foundation.org Cc: Lorenzo Pieralisi , Will Deacon , Catalin Marinas , Robin Murphy , Marc Zyngier , Joerg Roedel , "Rafael J. Wysocki" , Tomasz Nowicki , Hanjun Guo , Jon Masters , Sinan Kaya , linux-acpi@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH v2 03/15] arm64: mm: change IOMMU notifier action to attach DMA ops Date: Tue, 7 Jun 2016 14:30:58 +0100 Message-Id: <1465306270-27076-4-git-send-email-lorenzo.pieralisi@arm.com> X-Mailer: git-send-email 2.6.4 In-Reply-To: <1465306270-27076-1-git-send-email-lorenzo.pieralisi@arm.com> References: <1465306270-27076-1-git-send-email-lorenzo.pieralisi@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Current bus notifier in ARM64 (__iommu_attach_notifier) attempts to attach dma_ops to a device on BUS_NOTIFY_ADD_DEVICE action notification. This causes issues on ACPI based systems, where PCI devices can be added before the IOMMUs the devices are attached to had a chance to be probed, causing failures on attempts to attach dma_ops in that the domain for the respective IOMMU may not be set-up yet by the time the bus notifier is run. Devices dma_ops do not require to be set-up till the matching device drivers are probed. This means that instead of running the notifier attaching dma_ops to devices (__iommu_attach_notifier) on BUS_NOTIFY_ADD_DEVICE action, it can be run just before the device driver is bound to the device in question (on action BUS_NOTIFY_BIND_DRIVER) so that it is certain that its IOMMU group and domain are set-up accordingly at the time the notifier is triggered. This patch changes the notifier action upon which dma_ops are attached to devices and defer it to driver binding time, so that IOMMU devices have a chance to be probed and to register their bus notifiers before the dma_ops attach sequence for a device is actually carried out. Signed-off-by: Lorenzo Pieralisi Cc: Will Deacon Cc: Catalin Marinas Cc: Robin Murphy --- arch/arm64/mm/dma-mapping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c index c566ec8..79b0882 100644 --- a/arch/arm64/mm/dma-mapping.c +++ b/arch/arm64/mm/dma-mapping.c @@ -848,7 +848,7 @@ static int __iommu_attach_notifier(struct notifier_block *nb, { struct iommu_dma_notifier_data *master, *tmp; - if (action != BUS_NOTIFY_ADD_DEVICE) + if (action != BUS_NOTIFY_BIND_DRIVER) return 0; mutex_lock(&iommu_dma_notifier_lock); -- 2.6.4