From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH 3/5] iommu: Limit iommu_attach/detach_device to devices with their own group Date: Wed, 28 Jan 2015 14:35:24 +0000 Message-ID: <20150128143523.GR1569@arm.com> References: <1422317339-22620-1-git-send-email-joro@8bytes.org> <1422317339-22620-4-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: <1422317339-22620-4-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 12:08:57AM +0000, Joerg Roedel wrote: > From: Joerg Roedel > > This patch changes the behavior of the iommu_attach_device > and iommu_detach_device functions. With this change these > functions only work on devices that have their own group. > For all other devices the iommu_group_attach/detach > functions must be used. I like this a lot. Currently, if somebody detaches a device from the ARM SMMU, I end up detaching its group as well, which I've always found slightly odd. > Signed-off-by: Joerg Roedel > --- > drivers/iommu/iommu.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++---- > 1 file changed, 59 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 8f33ddd3..b63a550 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -51,6 +51,7 @@ struct iommu_group { > void (*iommu_data_release)(void *iommu_data); > char *name; > int id; > + unsigned dev_cnt; Is this actually used on a fast path, or can we just inspect the list of devices on the group instead? Will