From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sakari Ailus Subject: [PATCH 0/4] iommu: Prevent oops in iommu_get() and while arch_iommu is in use Date: Fri, 25 Mar 2011 17:17:43 +0200 Message-ID: <4D8CB217.1050909@maxwell.research.nokia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.nokia.com ([147.243.128.24]:63732 "EHLO mgw-da01.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750881Ab1CYPRv (ORCPT ); Fri, 25 Mar 2011 11:17:51 -0400 Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "linux-omap@vger.kernel.org" , "Doyu Hiroshi (Nokia-D/Helsinki)" , Laurent Pinchart , Cohen Hi, [Resend: the patches were accidentally sent to linux-media instead. Apologies.] This patchset is aimed to fix a problem in arch_iommu implementation references. When an actual arch_iommu implementation is not loaded while iommu_get() is being called results to a kernel oops, as well as removing an arch_iommu implementation which is in use. This patchset fixes both issues. The patchset assumes the arch_iommu is uninstalled at module unload time. Is this an acceptable requirement? Serialisation of the access to arch_iommu is done using mutex called arch_iommu_mutex. module_put() doesn't need to have the arch_iommu_mutex since when this gets called there won't be any users on the arch_iommu anyway. Comments are welcome. :-) Cheers, -- Sakari Ailus sakari.ailus@maxwell.research.nokia.com