From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH 1/2] iommu: call detach also for default_domain before attaching to new one Date: Tue, 16 Feb 2016 16:59:22 +0100 Message-ID: <20160216155922.GV18805@8bytes.org> References: <1455633632-16873-1-git-send-email-m.szyprowski@samsung.com> <1455633632-16873-2-git-send-email-m.szyprowski@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1455633632-16873-2-git-send-email-m.szyprowski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Marek Szyprowski Cc: linaro-mm-sig-cunTk1MwBs8s++Sfvej+rw@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Bartlomiej Zolnierkiewicz List-Id: iommu@lists.linux-foundation.org On Tue, Feb 16, 2016 at 03:40:31PM +0100, Marek Szyprowski wrote: > This patch ensures that devices attached to the default_domain will be > first detached from it before attaching to new domain. To avoid forward > declaration, __iommu_attach_group() function has been moved to new place > in the source code. Actually it was intentional to not invoke the detach_device call-back in the attach_device path. The reason is that detaching first and than attaching again leaves the device without a domain for a short period of time, until it is attached to the new domain. The attach_device call-back is supposed to handle this situation and just silently overwrite any other domain->device binding it finds for the device. This allows to do re-attachment with less iommu flushes and to get rid of the detach_device call-back at some point. Joerg