[PATCH v2 1/8] kobject: Add support for default attribute groups to kobj_type

From: Kimberly Brown
Date: Mon Apr 01 2019 - 22:51:26 EST


kobj_type currently uses a list of individual attributes to store
default attributes. Attribute groups are more flexible than a list of
attributes because groups provide support for attribute visibility. So,
add support for default attribute groups to kobj_type.

In future patches, the existing uses of kobj_typeâs attribute list will
be converted to attribute groups. When that is complete, kobj_typeâs
attribute list, âdefault_attrsâ, will be removed.

Signed-off-by: Kimberly Brown <kimbrownkd@xxxxxxxxx>
---
include/linux/kobject.h | 3 ++-
lib/kobject.c | 14 ++++++++++++++
2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index 1ab0d624fb36..e2ca0a292e21 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -139,7 +139,8 @@ static inline bool kobject_has_children(struct kobject *kobj)
struct kobj_type {
void (*release)(struct kobject *kobj);
const struct sysfs_ops *sysfs_ops;
- struct attribute **default_attrs;
+ struct attribute **default_attrs; /* use default_groups instead */
+ const struct attribute_group **default_groups;
const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
const void *(*namespace)(struct kobject *kobj);
void (*get_ownership)(struct kobject *kobj, kuid_t *uid, kgid_t *gid);
diff --git a/lib/kobject.c b/lib/kobject.c
index aa89edcd2b63..ede40005db28 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -82,6 +82,7 @@ static int populate_dir(struct kobject *kobj)

static int create_dir(struct kobject *kobj)
{
+ const struct kobj_type *ktype = get_ktype(kobj);
const struct kobj_ns_type_operations *ops;
int error;

@@ -95,6 +96,14 @@ static int create_dir(struct kobject *kobj)
return error;
}

+ if (ktype) {
+ error = sysfs_create_groups(kobj, ktype->default_groups);
+ if (error) {
+ sysfs_remove_dir(kobj);
+ return error;
+ }
+ }
+
/*
* @kobj->sd may be deleted by an ancestor going away. Hold an
* extra reference so that it stays until @kobj is gone.
@@ -584,11 +593,16 @@ EXPORT_SYMBOL_GPL(kobject_move);
void kobject_del(struct kobject *kobj)
{
struct kernfs_node *sd;
+ const struct kobj_type *ktype = get_ktype(kobj);

if (!kobj)
return;

sd = kobj->sd;
+
+ if (ktype)
+ sysfs_remove_groups(kobj, ktype->default_groups);
+
sysfs_remove_dir(kobj);
sysfs_put(sd);

--
2.17.1