Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758451Ab3CYO2t (ORCPT ); Mon, 25 Mar 2013 10:28:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:65001 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756682Ab3CYO2s (ORCPT ); Mon, 25 Mar 2013 10:28:48 -0400 Message-ID: <1364221712.24132.632.camel@bling.home> Subject: Re: [PATCH] iommu: add a function to find an iommu group by id From: Alex Williamson To: Alexey Kardashevskiy Cc: Benjamin Herrenschmidt , David Gibson , Joerg Roedel , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Date: Mon, 25 Mar 2013 08:28:32 -0600 In-Reply-To: <1364167429-6432-1-git-send-email-aik@ozlabs.ru> References: <1364167429-6432-1-git-send-email-aik@ozlabs.ru> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2736 Lines: 86 On Mon, 2013-03-25 at 10:23 +1100, Alexey Kardashevskiy wrote: > As IOMMU groups are exposed to the user space by their numbers, > the user space can use them in various kernel APIs so the kernel > might need an API to find a group by its ID. > > As an example, QEMU VFIO on PPC64 platform needs it to associate > a logical bus number (LIOBN) with a specific IOMMU group in order > to support in-kernel handling of DMA map/unmap requests. > > The patch adds the iommu_group_get_by_id(id) function which performs > such search. Subject: [PATCH v3].... v2 was the last one, where's the changelog for v3? > v2: fixed reference counting. > > Signed-off-by: Alexey Kardashevskiy > --- Acked-by: Alex Williamson > drivers/iommu/iommu.c | 29 +++++++++++++++++++++++++++++ > include/linux/iommu.h | 1 + > 2 files changed, 30 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 1065a1a..0de83eb 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -204,6 +204,35 @@ again: > } > EXPORT_SYMBOL_GPL(iommu_group_alloc); > > +struct iommu_group *iommu_group_get_by_id(int id) > +{ > + struct kobject *group_kobj; > + struct iommu_group *group; > + const char *name; > + > + if (!iommu_group_kset) > + return NULL; > + > + name = kasprintf(GFP_KERNEL, "%d", id); > + if (!name) > + return NULL; > + > + group_kobj = kset_find_obj(iommu_group_kset, name); > + kfree(name); > + > + if (!group_kobj) > + return NULL; > + > + group = container_of(group_kobj, struct iommu_group, kobj); > + BUG_ON(group->id != id); > + > + kobject_get(group->devices_kobj); > + kobject_put(&group->kobj); > + > + return group; > +} > +EXPORT_SYMBOL_GPL(iommu_group_get_by_id); > + > /** > * iommu_group_get_iommudata - retrieve iommu_data registered for a group > * @group: the group > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index f3b99e1..00e5d7d 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -113,6 +113,7 @@ struct iommu_ops { > extern int bus_set_iommu(struct bus_type *bus, struct iommu_ops *ops); > extern bool iommu_present(struct bus_type *bus); > extern struct iommu_domain *iommu_domain_alloc(struct bus_type *bus); > +extern struct iommu_group *iommu_group_get_by_id(int id); > extern void iommu_domain_free(struct iommu_domain *domain); > extern int iommu_attach_device(struct iommu_domain *domain, > struct device *dev); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/