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driver core: class.c: convert to only use class_to_subsys

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Now that class_to_subsys() can be used to get access to the internal
class private pointer, convert the remaining few places in class.c that
were accessing the pointer directly to use class_to_subsys() instead.

By doing this, the need for class_get() and class_put() goes away as no
one actually tries to increment the class structures anymore, only the
internal dynamic one.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230325194234.46588-2-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2023-03-25 20:42:34 +01:00
parent 884f8ce42c
commit 7b884b7f24
1 changed files with 61 additions and 52 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

113
drivers/base/class.c
View file

@ -66,24 +66,6 @@ static struct subsys_private *class_to_subsys(const struct class *class)
return sp; return sp;
} }
static const struct class *class_get(const struct class *class)
{
struct subsys_private *sp = class_to_subsys(class);
if (sp)
return class;
return NULL;
}
static void class_put(const struct class *class)
{
struct subsys_private *sp = class_to_subsys(class);
/* two puts are required as the call to bus_to_subsys incremented it again */
subsys_put(sp);
subsys_put(sp);
}
static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr, static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr,
char *buf) char *buf)
{ {
@ -148,13 +130,15 @@ static const struct kobj_type class_ktype = {
int class_create_file_ns(const struct class *cls, const struct class_attribute *attr, int class_create_file_ns(const struct class *cls, const struct class_attribute *attr,
const void *ns) const void *ns)
{ {
struct subsys_private *sp = class_to_subsys(cls);
int error; int error;
if (cls) if (!sp)
error = sysfs_create_file_ns(&cls->p->subsys.kobj, return -EINVAL;
&attr->attr, ns);
else error = sysfs_create_file_ns(&sp->subsys.kobj, &attr->attr, ns);
error = -EINVAL; subsys_put(sp);
return error; return error;
} }
EXPORT_SYMBOL_GPL(class_create_file_ns); EXPORT_SYMBOL_GPL(class_create_file_ns);
@ -162,8 +146,13 @@ EXPORT_SYMBOL_GPL(class_create_file_ns);
void class_remove_file_ns(const struct class *cls, const struct class_attribute *attr, void class_remove_file_ns(const struct class *cls, const struct class_attribute *attr,
const void *ns) const void *ns)
{ {
if (cls) struct subsys_private *sp = class_to_subsys(cls);
sysfs_remove_file_ns(&cls->p->subsys.kobj, &attr->attr, ns);
if (!sp)
return;
sysfs_remove_file_ns(&sp->subsys.kobj, &attr->attr, ns);
subsys_put(sp);
} }
EXPORT_SYMBOL_GPL(class_remove_file_ns); EXPORT_SYMBOL_GPL(class_remove_file_ns);
@ -187,18 +176,6 @@ static void klist_class_dev_put(struct klist_node *n)
put_device(dev); put_device(dev);
} }
static int class_add_groups(const struct class *cls,
const struct attribute_group **groups)
{
return sysfs_create_groups(&cls->p->subsys.kobj, groups);
}
static void class_remove_groups(const struct class *cls,
const struct attribute_group **groups)
{
return sysfs_remove_groups(&cls->p->subsys.kobj, groups);
}
int class_register(struct class *cls) int class_register(struct class *cls)
{ {
struct subsys_private *cp; struct subsys_private *cp;
@ -235,8 +212,7 @@ int class_register(struct class *cls)
if (error) if (error)
goto err_out; goto err_out;
error = class_add_groups(class_get(cls), cls->class_groups); error = sysfs_create_groups(&cp->subsys.kobj, cls->class_groups);
class_put(cls);
if (error) { if (error) {
kobject_del(&cp->subsys.kobj); kobject_del(&cp->subsys.kobj);
kfree_const(cp->subsys.kobj.name); kfree_const(cp->subsys.kobj.name);
@ -253,9 +229,16 @@ EXPORT_SYMBOL_GPL(class_register);
void class_unregister(const struct class *cls) void class_unregister(const struct class *cls)
{ {
struct subsys_private *sp = class_to_subsys(cls);
if (!sp)
return;
pr_debug("device class '%s': unregistering\n", cls->name); pr_debug("device class '%s': unregistering\n", cls->name);
class_remove_groups(cls, cls->class_groups);
kset_unregister(&cls->p->subsys); sysfs_remove_groups(&sp->subsys.kobj, cls->class_groups);
kset_unregister(&sp->subsys);
subsys_put(sp);
} }
EXPORT_SYMBOL_GPL(class_unregister); EXPORT_SYMBOL_GPL(class_unregister);
@ -334,11 +317,15 @@ EXPORT_SYMBOL_GPL(class_destroy);
void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class, void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class,
const struct device *start, const struct device_type *type) const struct device *start, const struct device_type *type)
{ {
struct subsys_private *sp = class_to_subsys(class);
struct klist_node *start_knode = NULL; struct klist_node *start_knode = NULL;
if (!sp)
return;
if (start) if (start)
start_knode = &start->p->knode_class; start_knode = &start->p->knode_class;
klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode); klist_iter_init_node(&sp->klist_devices, &iter->ki, start_knode);
iter->type = type; iter->type = type;
} }
EXPORT_SYMBOL_GPL(class_dev_iter_init); EXPORT_SYMBOL_GPL(class_dev_iter_init);
@ -405,13 +392,14 @@ EXPORT_SYMBOL_GPL(class_dev_iter_exit);
int class_for_each_device(const struct class *class, const struct device *start, int class_for_each_device(const struct class *class, const struct device *start,
void *data, int (*fn)(struct device *, void *)) void *data, int (*fn)(struct device *, void *))
{ {
struct subsys_private *sp = class_to_subsys(class);
struct class_dev_iter iter; struct class_dev_iter iter;
struct device *dev; struct device *dev;
int error = 0; int error = 0;
if (!class) if (!class)
return -EINVAL; return -EINVAL;
if (!class->p) { if (!sp) {
WARN(1, "%s called for class '%s' before it was initialized", WARN(1, "%s called for class '%s' before it was initialized",
__func__, class->name); __func__, class->name);
return -EINVAL; return -EINVAL;
@ -424,6 +412,7 @@ int class_for_each_device(const struct class *class, const struct device *start,
break; break;
} }
class_dev_iter_exit(&iter); class_dev_iter_exit(&iter);
subsys_put(sp);
return error; return error;
} }
@ -453,12 +442,13 @@ struct device *class_find_device(const struct class *class, const struct device
const void *data, const void *data,
int (*match)(struct device *, const void *)) int (*match)(struct device *, const void *))
{ {
struct subsys_private *sp = class_to_subsys(class);
struct class_dev_iter iter; struct class_dev_iter iter;
struct device *dev; struct device *dev;
if (!class) if (!class)
return NULL; return NULL;
if (!class->p) { if (!sp) {
WARN(1, "%s called for class '%s' before it was initialized", WARN(1, "%s called for class '%s' before it was initialized",
__func__, class->name); __func__, class->name);
return NULL; return NULL;
@ -472,6 +462,7 @@ struct device *class_find_device(const struct class *class, const struct device
} }
} }
class_dev_iter_exit(&iter); class_dev_iter_exit(&iter);
subsys_put(sp);
return dev; return dev;
} }
@ -479,6 +470,7 @@ EXPORT_SYMBOL_GPL(class_find_device);
int class_interface_register(struct class_interface *class_intf) int class_interface_register(struct class_interface *class_intf)
{ {
struct subsys_private *sp;
const struct class *parent; const struct class *parent;
struct class_dev_iter iter; struct class_dev_iter iter;
struct device *dev; struct device *dev;
@ -486,19 +478,25 @@ int class_interface_register(struct class_interface *class_intf)
if (!class_intf || !class_intf->class) if (!class_intf || !class_intf->class)
return -ENODEV; return -ENODEV;
parent = class_get(class_intf->class); parent = class_intf->class;
if (!parent) sp = class_to_subsys(parent);
if (!sp)
return -EINVAL; return -EINVAL;
mutex_lock(&parent->p->mutex); /*
list_add_tail(&class_intf->node, &parent->p->interfaces); * Reference in sp is now incremented and will be dropped when
* the interface is removed in the call to class_interface_unregister()
*/
mutex_lock(&sp->mutex);
list_add_tail(&class_intf->node, &sp->interfaces);
if (class_intf->add_dev) { if (class_intf->add_dev) {
class_dev_iter_init(&iter, parent, NULL, NULL); class_dev_iter_init(&iter, parent, NULL, NULL);
while ((dev = class_dev_iter_next(&iter))) while ((dev = class_dev_iter_next(&iter)))
class_intf->add_dev(dev, class_intf); class_intf->add_dev(dev, class_intf);
class_dev_iter_exit(&iter); class_dev_iter_exit(&iter);
} }
mutex_unlock(&parent->p->mutex); mutex_unlock(&sp->mutex);
return 0; return 0;
} }
@ -506,6 +504,7 @@ EXPORT_SYMBOL_GPL(class_interface_register);
void class_interface_unregister(struct class_interface *class_intf) void class_interface_unregister(struct class_interface *class_intf)
{ {
struct subsys_private *sp;
struct class *parent = class_intf->class; struct class *parent = class_intf->class;
struct class_dev_iter iter; struct class_dev_iter iter;
struct device *dev; struct device *dev;
@ -513,7 +512,11 @@ void class_interface_unregister(struct class_interface *class_intf)
if (!parent) if (!parent)
return; return;
mutex_lock(&parent->p->mutex); sp = class_to_subsys(parent);
if (!sp)
return;
mutex_lock(&sp->mutex);
list_del_init(&class_intf->node); list_del_init(&class_intf->node);
if (class_intf->remove_dev) { if (class_intf->remove_dev) {
class_dev_iter_init(&iter, parent, NULL, NULL); class_dev_iter_init(&iter, parent, NULL, NULL);
@ -521,9 +524,15 @@ void class_interface_unregister(struct class_interface *class_intf)
class_intf->remove_dev(dev, class_intf); class_intf->remove_dev(dev, class_intf);
class_dev_iter_exit(&iter); class_dev_iter_exit(&iter);
} }
mutex_unlock(&parent->p->mutex); mutex_unlock(&sp->mutex);
class_put(parent); /*
* Decrement the reference count twice, once for the class_to_subsys()
* call in the start of this function, and the second one from the
* reference increment in class_interface_register()
*/
subsys_put(sp);
subsys_put(sp);
} }
EXPORT_SYMBOL_GPL(class_interface_unregister); EXPORT_SYMBOL_GPL(class_interface_unregister);