From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753941AbcBAMQc (ORCPT ); Mon, 1 Feb 2016 07:16:32 -0500 Received: from prv-mh.provo.novell.com ([137.65.248.74]:56749 "EHLO prv-mh.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753671AbcBAMQa convert rfc822-to-8bit (ORCPT ); Mon, 1 Feb 2016 07:16:30 -0500 Message-Id: <56AF5AAB02000078000CCED7@prv-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.2.0 Date: Mon, 01 Feb 2016 05:16:27 -0700 From: "Jan Beulich" To: "David Vrabel" Cc: "xen-devel" , "Boris Ostrovsky" , "Konrad Rzeszutek Wilk" , Subject: Re: [PATCH] Xen/PCI: correct notifier used for device removal References: <56AF566002000078000CCE71@prv-mh.provo.novell.com> <56AF4911.8030208@citrix.com> In-Reply-To: <56AF4911.8030208@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 01.02.16 at 13:01, wrote: > On 01/02/16 11:58, Jan Beulich wrote: >> Commit 599bad38cf added BUS_NOTIFY_REMOVED_DEVICE in order to allow >> avoiding removal of IOMMU mappings before the driver actually got >> unbound from the device. Naturally we should be using this too. > > Because otherwise...? What happens if we don't make this change? > > Removing IOMMU mappings for a device when the driver is still bound to > the device looks wrong to me. Surely the device is still active and may > still be performing DMA at this point? Exactly - you answered your own question (as does the commit referred to). Jan