Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754991Ab3CXXYG (ORCPT ); Sun, 24 Mar 2013 19:24:06 -0400 Received: from mail-ie0-f171.google.com ([209.85.223.171]:43951 "EHLO mail-ie0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754053Ab3CXXYE (ORCPT ); Sun, 24 Mar 2013 19:24:04 -0400 From: Alexey Kardashevskiy To: Alex Williamson Cc: Alexey Kardashevskiy , Benjamin Herrenschmidt , David Gibson , Joerg Roedel , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org Subject: [PATCH] iommu: add a function to find an iommu group by id Date: Mon, 25 Mar 2013 10:23:49 +1100 Message-Id: <1364167429-6432-1-git-send-email-aik@ozlabs.ru> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: 1363968462.24132.611.camel@bling.home Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2411 Lines: 79 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. v2: fixed reference counting. Signed-off-by: Alexey Kardashevskiy --- 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); -- 1.7.10.4 -- 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/