From: James Morse <james.morse@arm.com> maillist inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IC03L1 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/commit/?h=mp... -------------------------------- ARM SMMU with MPAM support are able to mark streams of traffic with the QoS labels MPAM uses. The user-space interface for MPAM is the resctrl filesystem, which allows threads to be moved between groups, its natural to do the same for iommu_groups. The resctrl interface lists threads, so will also need to list iommu_groups, it will be necessary to walk the list of iommu_groups. To ensure this matches what user-space sees via sysfs, it is best to walk the kobjects. When making a change, resctrl will only have the id of a group. To avoid walking the list of kobjects in this case, add iommu_group_get_by_id(). Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Zeng Heng <zengheng4@huawei.com> --- drivers/iommu/iommu.c | 34 ++++++++++++++++++++++++++++++++++ include/linux/iommu.h | 12 ++++++++++++ 2 files changed, 46 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 8562abdeced1..faffa07c5e88 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -1016,6 +1016,40 @@ struct iommu_group *iommu_group_alloc(void) } EXPORT_SYMBOL_GPL(iommu_group_alloc); +struct iommu_group *iommu_group_get_from_kobj(struct kobject *group_kobj) +{ + struct iommu_group *group; + + if (!iommu_group_kset || !group_kobj) + return NULL; + + group = container_of(group_kobj, struct iommu_group, kobj); + + kobject_get(group->devices_kobj); + kobject_put(&group->kobj); + + return group; +} + +struct iommu_group *iommu_group_get_by_id(int id) +{ + struct kobject *group_kobj; + 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); + + return iommu_group_get_from_kobj(group_kobj); +} +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 058a5d5ed92b..f0585e004e9e 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -969,6 +969,8 @@ extern bool iommu_present(const struct bus_type *bus); extern bool device_iommu_capable(struct device *dev, enum iommu_cap cap); extern bool iommu_group_has_isolated_msi(struct iommu_group *group); extern struct iommu_domain *iommu_domain_alloc(const struct bus_type *bus); +struct iommu_group *iommu_group_get_from_kobj(struct kobject *group_kobj); +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); @@ -1320,6 +1322,16 @@ static inline struct iommu_domain *iommu_domain_alloc(const struct bus_type *bus return NULL; } +static inline struct iommu_group *iommu_group_get_from_kobj(struct kobject *group_kobj) +{ + return NULL; +} + +static inline struct iommu_group *iommu_group_get_by_id(int id) +{ + return NULL; +} + static inline void iommu_domain_free(struct iommu_domain *domain) { } -- 2.25.1