From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH 4/5] iommu: Make sure a device is always attached to a domain Date: Wed, 28 Jan 2015 14:38:52 +0000 Message-ID: <20150128143852.GS1569@arm.com> References: <1422317339-22620-1-git-send-email-joro@8bytes.org> <1422317339-22620-5-git-send-email-joro@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1422317339-22620-5-git-send-email-joro-zLv9SwRftAIdnm+yROfE0A@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: Joerg Roedel Cc: "jroedel-l3A5Bk7waGM@public.gmane.org" , Laurent Pinchart , Heiko Stuebner , Arnd Bergmann , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , Thierry Reding , Kukjin Kim , David Woodhouse List-Id: iommu@lists.linux-foundation.org On Tue, Jan 27, 2015 at 12:08:58AM +0000, Joerg Roedel wrote: > From: Joerg Roedel > > Make use of the default domain and re-attach a device to it > when it is detached from another domain. Also enforce that a > device has to be in the default domain before it can be > attached to a different domain. > > Signed-off-by: Joerg Roedel > --- > drivers/iommu/iommu.c | 34 +++++++++++++++++++++++++++++++--- > 1 file changed, 31 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index b63a550..5080759 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -53,6 +53,7 @@ struct iommu_group { > int id; > unsigned dev_cnt; > struct iommu_domain *default_domain; > + struct iommu_domain *domain; > }; > > struct iommu_device { > @@ -1040,8 +1041,17 @@ static int iommu_group_do_attach_device(struct device *dev, void *data) > > int iommu_attach_group(struct iommu_domain *domain, struct iommu_group *group) > { > - return iommu_group_for_each_dev(group, domain, > - iommu_group_do_attach_device); > + int ret; > + > + if (group->default_domain && group->domain != group->default_domain) > + return -EBUSY; I think this is now racy with itself and detach, whereas before we always held the group->mutex by virtue of iommu_group_for_each_dev. Will