From 792bcc4263c56c520f454875df3752b374791d6e Mon Sep 17 00:00:00 2001
From: James Morse <james.morse@arm.com>
Date: Thu, 16 Sep 2021 16:45:41 +0100
Subject: [PATCH] kobject: Add kset_get_next_obj() to allow a kset to be walked
To expose iommu_groups via the resctrl filesystem, the resctrl driver
needs to be able to walk the list of iommu_groups. These are exposed
via sysfs as a kset.
Add kset_get_next_obj() to allow resctrl to walk the kobjects in the
kset.
Signed-off-by: James Morse <james.morse@arm.com>
---
include/linux/kobject.h | 2 ++
lib/kobject.c | 21 +++++++++++++++++++++
2 files changed, 23 insertions(+)
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index bdab370a24f4e..c5f8878836e06 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -205,6 +205,8 @@ static inline const struct kobj_type *get_ktype(const struct kobject *kobj)
extern struct kobject *kset_find_obj(struct kset *, const char *);
+struct kobject *kset_get_next_obj(struct kset *kset, struct kobject *prev);
+
/* The global /sys/kernel/ kobject for people to chain off of */
extern struct kobject *kernel_kobj;
/* The global /sys/kernel/mm/ kobject for people to chain off of */
diff --git a/lib/kobject.c b/lib/kobject.c
index 6e2f0bee35604..cbf41f3be53b7 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -907,6 +907,27 @@ struct kobject *kset_find_obj(struct kset *kset, const char *name)
}
EXPORT_SYMBOL_GPL(kset_find_obj);
+struct kobject *kset_get_next_obj(struct kset *kset, struct kobject *prev)
+{
+ struct kobject *k;
+
+ spin_lock(&kset->list_lock);
+
+ if (!prev)
+ k = list_first_entry_or_null(&kset->list, typeof(*k), entry);
+ else
+ k = list_next_entry(prev, entry);
+
+ if (list_entry_is_head(k, &kset->list, entry))
+ k = NULL;
+
+ kobject_get(k);
+ spin_unlock(&kset->list_lock);
+ kobject_put(prev);
+
+ return k;
+}
+
static void kset_release(struct kobject *kobj)
{
struct kset *kset = container_of(kobj, struct kset, kobj);
--
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