linux/drivers/base/bus.c
Dmitry Torokhov 1a6f2a7512 Driver core: allow certain drivers prohibit bind/unbind via sysfs
Platform drivers registered via platform_driver_probe() can be bound
to devices only once, upon registration, because discard their probe()
routines to save memory. Unbinding the driver through sysfs 'unbind'
leaves the device stranded and confuses users so let's not create
bind and unbind attributes for such drivers.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Éric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-10-30 14:59:51 -07:00

1060 lines
26 KiB
C

/*
* bus.c - bus driver management
*
* Copyright (c) 2002-3 Patrick Mochel
* Copyright (c) 2002-3 Open Source Development Labs
* Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
* Copyright (c) 2007 Novell Inc.
*
* This file is released under the GPLv2
*
*/
#include <linux/device.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/string.h>
#include "base.h"
#include "power/power.h"
#define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
#define to_bus(obj) container_of(obj, struct bus_type_private, subsys.kobj)
/*
* sysfs bindings for drivers
*/
#define to_drv_attr(_attr) container_of(_attr, struct driver_attribute, attr)
static int __must_check bus_rescan_devices_helper(struct device *dev,
void *data);
static struct bus_type *bus_get(struct bus_type *bus)
{
if (bus) {
kset_get(&bus->p->subsys);
return bus;
}
return NULL;
}
static void bus_put(struct bus_type *bus)
{
if (bus)
kset_put(&bus->p->subsys);
}
static ssize_t drv_attr_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct driver_attribute *drv_attr = to_drv_attr(attr);
struct driver_private *drv_priv = to_driver(kobj);
ssize_t ret = -EIO;
if (drv_attr->show)
ret = drv_attr->show(drv_priv->driver, buf);
return ret;
}
static ssize_t drv_attr_store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t count)
{
struct driver_attribute *drv_attr = to_drv_attr(attr);
struct driver_private *drv_priv = to_driver(kobj);
ssize_t ret = -EIO;
if (drv_attr->store)
ret = drv_attr->store(drv_priv->driver, buf, count);
return ret;
}
static struct sysfs_ops driver_sysfs_ops = {
.show = drv_attr_show,
.store = drv_attr_store,
};
static void driver_release(struct kobject *kobj)
{
struct driver_private *drv_priv = to_driver(kobj);
pr_debug("driver: '%s': %s\n", kobject_name(kobj), __func__);
kfree(drv_priv);
}
static struct kobj_type driver_ktype = {
.sysfs_ops = &driver_sysfs_ops,
.release = driver_release,
};
/*
* sysfs bindings for buses
*/
static ssize_t bus_attr_show(struct kobject *kobj, struct attribute *attr,
char *buf)
{
struct bus_attribute *bus_attr = to_bus_attr(attr);
struct bus_type_private *bus_priv = to_bus(kobj);
ssize_t ret = 0;
if (bus_attr->show)
ret = bus_attr->show(bus_priv->bus, buf);
return ret;
}
static ssize_t bus_attr_store(struct kobject *kobj, struct attribute *attr,
const char *buf, size_t count)
{
struct bus_attribute *bus_attr = to_bus_attr(attr);
struct bus_type_private *bus_priv = to_bus(kobj);
ssize_t ret = 0;
if (bus_attr->store)
ret = bus_attr->store(bus_priv->bus, buf, count);
return ret;
}
static struct sysfs_ops bus_sysfs_ops = {
.show = bus_attr_show,
.store = bus_attr_store,
};
int bus_create_file(struct bus_type *bus, struct bus_attribute *attr)
{
int error;
if (bus_get(bus)) {
error = sysfs_create_file(&bus->p->subsys.kobj, &attr->attr);
bus_put(bus);
} else
error = -EINVAL;
return error;
}
EXPORT_SYMBOL_GPL(bus_create_file);
void bus_remove_file(struct bus_type *bus, struct bus_attribute *attr)
{
if (bus_get(bus)) {
sysfs_remove_file(&bus->p->subsys.kobj, &attr->attr);
bus_put(bus);
}
}
EXPORT_SYMBOL_GPL(bus_remove_file);
static struct kobj_type bus_ktype = {
.sysfs_ops = &bus_sysfs_ops,
};
static int bus_uevent_filter(struct kset *kset, struct kobject *kobj)
{
struct kobj_type *ktype = get_ktype(kobj);
if (ktype == &bus_ktype)
return 1;
return 0;
}
static struct kset_uevent_ops bus_uevent_ops = {
.filter = bus_uevent_filter,
};
static struct kset *bus_kset;
#ifdef CONFIG_HOTPLUG
/* Manually detach a device from its associated driver. */
static ssize_t driver_unbind(struct device_driver *drv,
const char *buf, size_t count)
{
struct bus_type *bus = bus_get(drv->bus);
struct device *dev;
int err = -ENODEV;
dev = bus_find_device_by_name(bus, NULL, buf);
if (dev && dev->driver == drv) {
if (dev->parent) /* Needed for USB */
down(&dev->parent->sem);
device_release_driver(dev);
if (dev->parent)
up(&dev->parent->sem);
err = count;
}
put_device(dev);
bus_put(bus);
return err;
}
static DRIVER_ATTR(unbind, S_IWUSR, NULL, driver_unbind);
/*
* Manually attach a device to a driver.
* Note: the driver must want to bind to the device,
* it is not possible to override the driver's id table.
*/
static ssize_t driver_bind(struct device_driver *drv,
const char *buf, size_t count)
{
struct bus_type *bus = bus_get(drv->bus);
struct device *dev;
int err = -ENODEV;
dev = bus_find_device_by_name(bus, NULL, buf);
if (dev && dev->driver == NULL && driver_match_device(drv, dev)) {
if (dev->parent) /* Needed for USB */
down(&dev->parent->sem);
down(&dev->sem);
err = driver_probe_device(drv, dev);
up(&dev->sem);
if (dev->parent)
up(&dev->parent->sem);
if (err > 0) {
/* success */
err = count;
} else if (err == 0) {
/* driver didn't accept device */
err = -ENODEV;
}
}
put_device(dev);
bus_put(bus);
return err;
}
static DRIVER_ATTR(bind, S_IWUSR, NULL, driver_bind);
static ssize_t show_drivers_autoprobe(struct bus_type *bus, char *buf)
{
return sprintf(buf, "%d\n", bus->p->drivers_autoprobe);
}
static ssize_t store_drivers_autoprobe(struct bus_type *bus,
const char *buf, size_t count)
{
if (buf[0] == '0')
bus->p->drivers_autoprobe = 0;
else
bus->p->drivers_autoprobe = 1;
return count;
}
static ssize_t store_drivers_probe(struct bus_type *bus,
const char *buf, size_t count)
{
struct device *dev;
dev = bus_find_device_by_name(bus, NULL, buf);
if (!dev)
return -ENODEV;
if (bus_rescan_devices_helper(dev, NULL) != 0)
return -EINVAL;
return count;
}
#endif
static struct device *next_device(struct klist_iter *i)
{
struct klist_node *n = klist_next(i);
struct device *dev = NULL;
struct device_private *dev_prv;
if (n) {
dev_prv = to_device_private_bus(n);
dev = dev_prv->device;
}
return dev;
}
/**
* bus_for_each_dev - device iterator.
* @bus: bus type.
* @start: device to start iterating from.
* @data: data for the callback.
* @fn: function to be called for each device.
*
* Iterate over @bus's list of devices, and call @fn for each,
* passing it @data. If @start is not NULL, we use that device to
* begin iterating from.
*
* We check the return of @fn each time. If it returns anything
* other than 0, we break out and return that value.
*
* NOTE: The device that returns a non-zero value is not retained
* in any way, nor is its refcount incremented. If the caller needs
* to retain this data, it should do so, and increment the reference
* count in the supplied callback.
*/
int bus_for_each_dev(struct bus_type *bus, struct device *start,
void *data, int (*fn)(struct device *, void *))
{
struct klist_iter i;
struct device *dev;
int error = 0;
if (!bus)
return -EINVAL;
klist_iter_init_node(&bus->p->klist_devices, &i,
(start ? &start->p->knode_bus : NULL));
while ((dev = next_device(&i)) && !error)
error = fn(dev, data);
klist_iter_exit(&i);
return error;
}
EXPORT_SYMBOL_GPL(bus_for_each_dev);
/**
* bus_find_device - device iterator for locating a particular device.
* @bus: bus type
* @start: Device to begin with
* @data: Data to pass to match function
* @match: Callback function to check device
*
* This is similar to the bus_for_each_dev() function above, but it
* returns a reference to a device that is 'found' for later use, as
* determined by the @match callback.
*
* The callback should return 0 if the device doesn't match and non-zero
* if it does. If the callback returns non-zero, this function will
* return to the caller and not iterate over any more devices.
*/
struct device *bus_find_device(struct bus_type *bus,
struct device *start, void *data,
int (*match)(struct device *dev, void *data))
{
struct klist_iter i;
struct device *dev;
if (!bus)
return NULL;
klist_iter_init_node(&bus->p->klist_devices, &i,
(start ? &start->p->knode_bus : NULL));
while ((dev = next_device(&i)))
if (match(dev, data) && get_device(dev))
break;
klist_iter_exit(&i);
return dev;
}
EXPORT_SYMBOL_GPL(bus_find_device);
static int match_name(struct device *dev, void *data)
{
const char *name = data;
return sysfs_streq(name, dev_name(dev));
}
/**
* bus_find_device_by_name - device iterator for locating a particular device of a specific name
* @bus: bus type
* @start: Device to begin with
* @name: name of the device to match
*
* This is similar to the bus_find_device() function above, but it handles
* searching by a name automatically, no need to write another strcmp matching
* function.
*/
struct device *bus_find_device_by_name(struct bus_type *bus,
struct device *start, const char *name)
{
return bus_find_device(bus, start, (void *)name, match_name);
}
EXPORT_SYMBOL_GPL(bus_find_device_by_name);
static struct device_driver *next_driver(struct klist_iter *i)
{
struct klist_node *n = klist_next(i);
struct driver_private *drv_priv;
if (n) {
drv_priv = container_of(n, struct driver_private, knode_bus);
return drv_priv->driver;
}
return NULL;
}
/**
* bus_for_each_drv - driver iterator
* @bus: bus we're dealing with.
* @start: driver to start iterating on.
* @data: data to pass to the callback.
* @fn: function to call for each driver.
*
* This is nearly identical to the device iterator above.
* We iterate over each driver that belongs to @bus, and call
* @fn for each. If @fn returns anything but 0, we break out
* and return it. If @start is not NULL, we use it as the head
* of the list.
*
* NOTE: we don't return the driver that returns a non-zero
* value, nor do we leave the reference count incremented for that
* driver. If the caller needs to know that info, it must set it
* in the callback. It must also be sure to increment the refcount
* so it doesn't disappear before returning to the caller.
*/
int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
void *data, int (*fn)(struct device_driver *, void *))
{
struct klist_iter i;
struct device_driver *drv;
int error = 0;
if (!bus)
return -EINVAL;
klist_iter_init_node(&bus->p->klist_drivers, &i,
start ? &start->p->knode_bus : NULL);
while ((drv = next_driver(&i)) && !error)
error = fn(drv, data);
klist_iter_exit(&i);
return error;
}
EXPORT_SYMBOL_GPL(bus_for_each_drv);
static int device_add_attrs(struct bus_type *bus, struct device *dev)
{
int error = 0;
int i;
if (!bus->dev_attrs)
return 0;
for (i = 0; attr_name(bus->dev_attrs[i]); i++) {
error = device_create_file(dev, &bus->dev_attrs[i]);
if (error) {
while (--i >= 0)
device_remove_file(dev, &bus->dev_attrs[i]);
break;
}
}
return error;
}
static void device_remove_attrs(struct bus_type *bus, struct device *dev)
{
int i;
if (bus->dev_attrs) {
for (i = 0; attr_name(bus->dev_attrs[i]); i++)
device_remove_file(dev, &bus->dev_attrs[i]);
}
}
#ifdef CONFIG_SYSFS_DEPRECATED
static int make_deprecated_bus_links(struct device *dev)
{
return sysfs_create_link(&dev->kobj,
&dev->bus->p->subsys.kobj, "bus");
}
static void remove_deprecated_bus_links(struct device *dev)
{
sysfs_remove_link(&dev->kobj, "bus");
}
#else
static inline int make_deprecated_bus_links(struct device *dev) { return 0; }
static inline void remove_deprecated_bus_links(struct device *dev) { }
#endif
/**
* bus_add_device - add device to bus
* @dev: device being added
*
* - Add device's bus attributes.
* - Create links to device's bus.
* - Add the device to its bus's list of devices.
*/
int bus_add_device(struct device *dev)
{
struct bus_type *bus = bus_get(dev->bus);
int error = 0;
if (bus) {
pr_debug("bus: '%s': add device %s\n", bus->name, dev_name(dev));
error = device_add_attrs(bus, dev);
if (error)
goto out_put;
error = sysfs_create_link(&bus->p->devices_kset->kobj,
&dev->kobj, dev_name(dev));
if (error)
goto out_id;
error = sysfs_create_link(&dev->kobj,
&dev->bus->p->subsys.kobj, "subsystem");
if (error)
goto out_subsys;
error = make_deprecated_bus_links(dev);
if (error)
goto out_deprecated;
klist_add_tail(&dev->p->knode_bus, &bus->p->klist_devices);
}
return 0;
out_deprecated:
sysfs_remove_link(&dev->kobj, "subsystem");
out_subsys:
sysfs_remove_link(&bus->p->devices_kset->kobj, dev_name(dev));
out_id:
device_remove_attrs(bus, dev);
out_put:
bus_put(dev->bus);
return error;
}
/**
* bus_probe_device - probe drivers for a new device
* @dev: device to probe
*
* - Automatically probe for a driver if the bus allows it.
*/
void bus_probe_device(struct device *dev)
{
struct bus_type *bus = dev->bus;
int ret;
if (bus && bus->p->drivers_autoprobe) {
ret = device_attach(dev);
WARN_ON(ret < 0);
}
}
/**
* bus_remove_device - remove device from bus
* @dev: device to be removed
*
* - Remove symlink from bus's directory.
* - Delete device from bus's list.
* - Detach from its driver.
* - Drop reference taken in bus_add_device().
*/
void bus_remove_device(struct device *dev)
{
if (dev->bus) {
sysfs_remove_link(&dev->kobj, "subsystem");
remove_deprecated_bus_links(dev);
sysfs_remove_link(&dev->bus->p->devices_kset->kobj,
dev_name(dev));
device_remove_attrs(dev->bus, dev);
if (klist_node_attached(&dev->p->knode_bus))
klist_del(&dev->p->knode_bus);
pr_debug("bus: '%s': remove device %s\n",
dev->bus->name, dev_name(dev));
device_release_driver(dev);
bus_put(dev->bus);
}
}
static int driver_add_attrs(struct bus_type *bus, struct device_driver *drv)
{
int error = 0;
int i;
if (bus->drv_attrs) {
for (i = 0; attr_name(bus->drv_attrs[i]); i++) {
error = driver_create_file(drv, &bus->drv_attrs[i]);
if (error)
goto err;
}
}
done:
return error;
err:
while (--i >= 0)
driver_remove_file(drv, &bus->drv_attrs[i]);
goto done;
}
static void driver_remove_attrs(struct bus_type *bus,
struct device_driver *drv)
{
int i;
if (bus->drv_attrs) {
for (i = 0; attr_name(bus->drv_attrs[i]); i++)
driver_remove_file(drv, &bus->drv_attrs[i]);
}
}
#ifdef CONFIG_HOTPLUG
/*
* Thanks to drivers making their tables __devinit, we can't allow manual
* bind and unbind from userspace unless CONFIG_HOTPLUG is enabled.
*/
static int __must_check add_bind_files(struct device_driver *drv)
{
int ret;
ret = driver_create_file(drv, &driver_attr_unbind);
if (ret == 0) {
ret = driver_create_file(drv, &driver_attr_bind);
if (ret)
driver_remove_file(drv, &driver_attr_unbind);
}
return ret;
}
static void remove_bind_files(struct device_driver *drv)
{
driver_remove_file(drv, &driver_attr_bind);
driver_remove_file(drv, &driver_attr_unbind);
}
static BUS_ATTR(drivers_probe, S_IWUSR, NULL, store_drivers_probe);
static BUS_ATTR(drivers_autoprobe, S_IWUSR | S_IRUGO,
show_drivers_autoprobe, store_drivers_autoprobe);
static int add_probe_files(struct bus_type *bus)
{
int retval;
retval = bus_create_file(bus, &bus_attr_drivers_probe);
if (retval)
goto out;
retval = bus_create_file(bus, &bus_attr_drivers_autoprobe);
if (retval)
bus_remove_file(bus, &bus_attr_drivers_probe);
out:
return retval;
}
static void remove_probe_files(struct bus_type *bus)
{
bus_remove_file(bus, &bus_attr_drivers_autoprobe);
bus_remove_file(bus, &bus_attr_drivers_probe);
}
#else
static inline int add_bind_files(struct device_driver *drv) { return 0; }
static inline void remove_bind_files(struct device_driver *drv) {}
static inline int add_probe_files(struct bus_type *bus) { return 0; }
static inline void remove_probe_files(struct bus_type *bus) {}
#endif
static ssize_t driver_uevent_store(struct device_driver *drv,
const char *buf, size_t count)
{
enum kobject_action action;
if (kobject_action_type(buf, count, &action) == 0)
kobject_uevent(&drv->p->kobj, action);
return count;
}
static DRIVER_ATTR(uevent, S_IWUSR, NULL, driver_uevent_store);
/**
* bus_add_driver - Add a driver to the bus.
* @drv: driver.
*/
int bus_add_driver(struct device_driver *drv)
{
struct bus_type *bus;
struct driver_private *priv;
int error = 0;
bus = bus_get(drv->bus);
if (!bus)
return -EINVAL;
pr_debug("bus: '%s': add driver %s\n", bus->name, drv->name);
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv) {
error = -ENOMEM;
goto out_put_bus;
}
klist_init(&priv->klist_devices, NULL, NULL);
priv->driver = drv;
drv->p = priv;
priv->kobj.kset = bus->p->drivers_kset;
error = kobject_init_and_add(&priv->kobj, &driver_ktype, NULL,
"%s", drv->name);
if (error)
goto out_unregister;
if (drv->bus->p->drivers_autoprobe) {
error = driver_attach(drv);
if (error)
goto out_unregister;
}
klist_add_tail(&priv->knode_bus, &bus->p->klist_drivers);
module_add_driver(drv->owner, drv);
error = driver_create_file(drv, &driver_attr_uevent);
if (error) {
printk(KERN_ERR "%s: uevent attr (%s) failed\n",
__func__, drv->name);
}
error = driver_add_attrs(bus, drv);
if (error) {
/* How the hell do we get out of this pickle? Give up */
printk(KERN_ERR "%s: driver_add_attrs(%s) failed\n",
__func__, drv->name);
}
if (!drv->suppress_bind_attrs) {
error = add_bind_files(drv);
if (error) {
/* Ditto */
printk(KERN_ERR "%s: add_bind_files(%s) failed\n",
__func__, drv->name);
}
}
kobject_uevent(&priv->kobj, KOBJ_ADD);
return 0;
out_unregister:
kfree(drv->p);
drv->p = NULL;
kobject_put(&priv->kobj);
out_put_bus:
bus_put(bus);
return error;
}
/**
* bus_remove_driver - delete driver from bus's knowledge.
* @drv: driver.
*
* Detach the driver from the devices it controls, and remove
* it from its bus's list of drivers. Finally, we drop the reference
* to the bus we took in bus_add_driver().
*/
void bus_remove_driver(struct device_driver *drv)
{
if (!drv->bus)
return;
if (!drv->suppress_bind_attrs)
remove_bind_files(drv);
driver_remove_attrs(drv->bus, drv);
driver_remove_file(drv, &driver_attr_uevent);
klist_remove(&drv->p->knode_bus);
pr_debug("bus: '%s': remove driver %s\n", drv->bus->name, drv->name);
driver_detach(drv);
module_remove_driver(drv);
kobject_put(&drv->p->kobj);
bus_put(drv->bus);
}
/* Helper for bus_rescan_devices's iter */
static int __must_check bus_rescan_devices_helper(struct device *dev,
void *data)
{
int ret = 0;
if (!dev->driver) {
if (dev->parent) /* Needed for USB */
down(&dev->parent->sem);
ret = device_attach(dev);
if (dev->parent)
up(&dev->parent->sem);
}
return ret < 0 ? ret : 0;
}
/**
* bus_rescan_devices - rescan devices on the bus for possible drivers
* @bus: the bus to scan.
*
* This function will look for devices on the bus with no driver
* attached and rescan it against existing drivers to see if it matches
* any by calling device_attach() for the unbound devices.
*/
int bus_rescan_devices(struct bus_type *bus)
{
return bus_for_each_dev(bus, NULL, NULL, bus_rescan_devices_helper);
}
EXPORT_SYMBOL_GPL(bus_rescan_devices);
/**
* device_reprobe - remove driver for a device and probe for a new driver
* @dev: the device to reprobe
*
* This function detaches the attached driver (if any) for the given
* device and restarts the driver probing process. It is intended
* to use if probing criteria changed during a devices lifetime and
* driver attachment should change accordingly.
*/
int device_reprobe(struct device *dev)
{
if (dev->driver) {
if (dev->parent) /* Needed for USB */
down(&dev->parent->sem);
device_release_driver(dev);
if (dev->parent)
up(&dev->parent->sem);
}
return bus_rescan_devices_helper(dev, NULL);
}
EXPORT_SYMBOL_GPL(device_reprobe);
/**
* find_bus - locate bus by name.
* @name: name of bus.
*
* Call kset_find_obj() to iterate over list of buses to
* find a bus by name. Return bus if found.
*
* Note that kset_find_obj increments bus' reference count.
*/
#if 0
struct bus_type *find_bus(char *name)
{
struct kobject *k = kset_find_obj(bus_kset, name);
return k ? to_bus(k) : NULL;
}
#endif /* 0 */
/**
* bus_add_attrs - Add default attributes for this bus.
* @bus: Bus that has just been registered.
*/
static int bus_add_attrs(struct bus_type *bus)
{
int error = 0;
int i;
if (bus->bus_attrs) {
for (i = 0; attr_name(bus->bus_attrs[i]); i++) {
error = bus_create_file(bus, &bus->bus_attrs[i]);
if (error)
goto err;
}
}
done:
return error;
err:
while (--i >= 0)
bus_remove_file(bus, &bus->bus_attrs[i]);
goto done;
}
static void bus_remove_attrs(struct bus_type *bus)
{
int i;
if (bus->bus_attrs) {
for (i = 0; attr_name(bus->bus_attrs[i]); i++)
bus_remove_file(bus, &bus->bus_attrs[i]);
}
}
static void klist_devices_get(struct klist_node *n)
{
struct device_private *dev_prv = to_device_private_bus(n);
struct device *dev = dev_prv->device;
get_device(dev);
}
static void klist_devices_put(struct klist_node *n)
{
struct device_private *dev_prv = to_device_private_bus(n);
struct device *dev = dev_prv->device;
put_device(dev);
}
static ssize_t bus_uevent_store(struct bus_type *bus,
const char *buf, size_t count)
{
enum kobject_action action;
if (kobject_action_type(buf, count, &action) == 0)
kobject_uevent(&bus->p->subsys.kobj, action);
return count;
}
static BUS_ATTR(uevent, S_IWUSR, NULL, bus_uevent_store);
/**
* bus_register - register a bus with the system.
* @bus: bus.
*
* Once we have that, we registered the bus with the kobject
* infrastructure, then register the children subsystems it has:
* the devices and drivers that belong to the bus.
*/
int bus_register(struct bus_type *bus)
{
int retval;
struct bus_type_private *priv;
priv = kzalloc(sizeof(struct bus_type_private), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->bus = bus;
bus->p = priv;
BLOCKING_INIT_NOTIFIER_HEAD(&priv->bus_notifier);
retval = kobject_set_name(&priv->subsys.kobj, "%s", bus->name);
if (retval)
goto out;
priv->subsys.kobj.kset = bus_kset;
priv->subsys.kobj.ktype = &bus_ktype;
priv->drivers_autoprobe = 1;
retval = kset_register(&priv->subsys);
if (retval)
goto out;
retval = bus_create_file(bus, &bus_attr_uevent);
if (retval)
goto bus_uevent_fail;
priv->devices_kset = kset_create_and_add("devices", NULL,
&priv->subsys.kobj);
if (!priv->devices_kset) {
retval = -ENOMEM;
goto bus_devices_fail;
}
priv->drivers_kset = kset_create_and_add("drivers", NULL,
&priv->subsys.kobj);
if (!priv->drivers_kset) {
retval = -ENOMEM;
goto bus_drivers_fail;
}
klist_init(&priv->klist_devices, klist_devices_get, klist_devices_put);
klist_init(&priv->klist_drivers, NULL, NULL);
retval = add_probe_files(bus);
if (retval)
goto bus_probe_files_fail;
retval = bus_add_attrs(bus);
if (retval)
goto bus_attrs_fail;
pr_debug("bus: '%s': registered\n", bus->name);
return 0;
bus_attrs_fail:
remove_probe_files(bus);
bus_probe_files_fail:
kset_unregister(bus->p->drivers_kset);
bus_drivers_fail:
kset_unregister(bus->p->devices_kset);
bus_devices_fail:
bus_remove_file(bus, &bus_attr_uevent);
bus_uevent_fail:
kset_unregister(&bus->p->subsys);
kfree(bus->p);
out:
bus->p = NULL;
return retval;
}
EXPORT_SYMBOL_GPL(bus_register);
/**
* bus_unregister - remove a bus from the system
* @bus: bus.
*
* Unregister the child subsystems and the bus itself.
* Finally, we call bus_put() to release the refcount
*/
void bus_unregister(struct bus_type *bus)
{
pr_debug("bus: '%s': unregistering\n", bus->name);
bus_remove_attrs(bus);
remove_probe_files(bus);
kset_unregister(bus->p->drivers_kset);
kset_unregister(bus->p->devices_kset);
bus_remove_file(bus, &bus_attr_uevent);
kset_unregister(&bus->p->subsys);
kfree(bus->p);
bus->p = NULL;
}
EXPORT_SYMBOL_GPL(bus_unregister);
int bus_register_notifier(struct bus_type *bus, struct notifier_block *nb)
{
return blocking_notifier_chain_register(&bus->p->bus_notifier, nb);
}
EXPORT_SYMBOL_GPL(bus_register_notifier);
int bus_unregister_notifier(struct bus_type *bus, struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&bus->p->bus_notifier, nb);
}
EXPORT_SYMBOL_GPL(bus_unregister_notifier);
struct kset *bus_get_kset(struct bus_type *bus)
{
return &bus->p->subsys;
}
EXPORT_SYMBOL_GPL(bus_get_kset);
struct klist *bus_get_device_klist(struct bus_type *bus)
{
return &bus->p->klist_devices;
}
EXPORT_SYMBOL_GPL(bus_get_device_klist);
/*
* Yes, this forcably breaks the klist abstraction temporarily. It
* just wants to sort the klist, not change reference counts and
* take/drop locks rapidly in the process. It does all this while
* holding the lock for the list, so objects can't otherwise be
* added/removed while we're swizzling.
*/
static void device_insertion_sort_klist(struct device *a, struct list_head *list,
int (*compare)(const struct device *a,
const struct device *b))
{
struct list_head *pos;
struct klist_node *n;
struct device_private *dev_prv;
struct device *b;
list_for_each(pos, list) {
n = container_of(pos, struct klist_node, n_node);
dev_prv = to_device_private_bus(n);
b = dev_prv->device;
if (compare(a, b) <= 0) {
list_move_tail(&a->p->knode_bus.n_node,
&b->p->knode_bus.n_node);
return;
}
}
list_move_tail(&a->p->knode_bus.n_node, list);
}
void bus_sort_breadthfirst(struct bus_type *bus,
int (*compare)(const struct device *a,
const struct device *b))
{
LIST_HEAD(sorted_devices);
struct list_head *pos, *tmp;
struct klist_node *n;
struct device_private *dev_prv;
struct device *dev;
struct klist *device_klist;
device_klist = bus_get_device_klist(bus);
spin_lock(&device_klist->k_lock);
list_for_each_safe(pos, tmp, &device_klist->k_list) {
n = container_of(pos, struct klist_node, n_node);
dev_prv = to_device_private_bus(n);
dev = dev_prv->device;
device_insertion_sort_klist(dev, &sorted_devices, compare);
}
list_splice(&sorted_devices, &device_klist->k_list);
spin_unlock(&device_klist->k_lock);
}
EXPORT_SYMBOL_GPL(bus_sort_breadthfirst);
int __init buses_init(void)
{
bus_kset = kset_create_and_add("bus", &bus_uevent_ops, NULL);
if (!bus_kset)
return -ENOMEM;
return 0;
}