driver/base: implement subsys_virtual_register()

Kay tells me the most appropriate place to expose workqueues to
userland would be /sys/devices/virtual/workqueues/WQ_NAME which is
symlinked to /sys/bus/workqueue/devices/WQ_NAME and that we're lacking
a way to do that outside of driver core as virtual_device_parent()
isn't exported and there's no inteface to conveniently create a
virtual subsystem.

This patch implements subsys_virtual_register() by factoring out
subsys_register() from subsys_system_register() and using it with
virtual_device_parent() as the origin directory.  It's identical to
subsys_system_register() other than the origin directory but we aren't
gonna restrict the device names which should be used under it.

This will be used to expose workqueue attributes to userland.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
This commit is contained in:
Tejun Heo 2013-03-12 11:30:05 -07:00
Родитель 6dbe51c251
Коммит d73ce00422
4 изменённых файлов: 72 добавлений и 37 удалений

Просмотреть файл

@ -101,6 +101,8 @@ static inline int hypervisor_init(void) { return 0; }
extern int platform_bus_init(void);
extern void cpu_dev_init(void);
struct kobject *virtual_device_parent(struct device *dev);
extern int bus_add_device(struct device *dev);
extern void bus_probe_device(struct device *dev);
extern void bus_remove_device(struct device *dev);

Просмотреть файл

@ -1205,6 +1205,49 @@ static void system_root_device_release(struct device *dev)
{
kfree(dev);
}
static int subsys_register(struct bus_type *subsys,
const struct attribute_group **groups,
struct kobject *parent_of_root)
{
struct device *dev;
int err;
err = bus_register(subsys);
if (err < 0)
return err;
dev = kzalloc(sizeof(struct device), GFP_KERNEL);
if (!dev) {
err = -ENOMEM;
goto err_dev;
}
err = dev_set_name(dev, "%s", subsys->name);
if (err < 0)
goto err_name;
dev->kobj.parent = parent_of_root;
dev->groups = groups;
dev->release = system_root_device_release;
err = device_register(dev);
if (err < 0)
goto err_dev_reg;
subsys->dev_root = dev;
return 0;
err_dev_reg:
put_device(dev);
dev = NULL;
err_name:
kfree(dev);
err_dev:
bus_unregister(subsys);
return err;
}
/**
* subsys_system_register - register a subsystem at /sys/devices/system/
* @subsys: system subsystem
@ -1226,45 +1269,33 @@ static void system_root_device_release(struct device *dev)
int subsys_system_register(struct bus_type *subsys,
const struct attribute_group **groups)
{
struct device *dev;
int err;
err = bus_register(subsys);
if (err < 0)
return err;
dev = kzalloc(sizeof(struct device), GFP_KERNEL);
if (!dev) {
err = -ENOMEM;
goto err_dev;
}
err = dev_set_name(dev, "%s", subsys->name);
if (err < 0)
goto err_name;
dev->kobj.parent = &system_kset->kobj;
dev->groups = groups;
dev->release = system_root_device_release;
err = device_register(dev);
if (err < 0)
goto err_dev_reg;
subsys->dev_root = dev;
return 0;
err_dev_reg:
put_device(dev);
dev = NULL;
err_name:
kfree(dev);
err_dev:
bus_unregister(subsys);
return err;
return subsys_register(subsys, groups, &system_kset->kobj);
}
EXPORT_SYMBOL_GPL(subsys_system_register);
/**
* subsys_virtual_register - register a subsystem at /sys/devices/virtual/
* @subsys: virtual subsystem
* @groups: default attributes for the root device
*
* All 'virtual' subsystems have a /sys/devices/system/<name> root device
* with the name of the subystem. The root device can carry subsystem-wide
* attributes. All registered devices are below this single root device.
* There's no restriction on device naming. This is for kernel software
* constructs which need sysfs interface.
*/
int subsys_virtual_register(struct bus_type *subsys,
const struct attribute_group **groups)
{
struct kobject *virtual_dir;
virtual_dir = virtual_device_parent(NULL);
if (!virtual_dir)
return -ENOMEM;
return subsys_register(subsys, groups, virtual_dir);
}
int __init buses_init(void)
{
bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);

Просмотреть файл

@ -690,7 +690,7 @@ void device_initialize(struct device *dev)
set_dev_node(dev, -1);
}
static struct kobject *virtual_device_parent(struct device *dev)
struct kobject *virtual_device_parent(struct device *dev)
{
static struct kobject *virtual_dir = NULL;

Просмотреть файл

@ -302,6 +302,8 @@ void subsys_interface_unregister(struct subsys_interface *sif);
int subsys_system_register(struct bus_type *subsys,
const struct attribute_group **groups);
int subsys_virtual_register(struct bus_type *subsys,
const struct attribute_group **groups);
/**
* struct class - device classes