linux/drivers/base/driver.c
Stas Sergeev 16dc42e018 driver core: warn about duplicate driver names on the same bus
Currently an attempt to register multiple
drivers with the same name causes the
stack trace with some cryptic error message.
The attached patch adds the necessary check
and the clear error message.

Signed-off-by: Stas Sergeev <stsp@aknet.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-30 16:52:47 -07:00

280 lines
6.7 KiB
C

/*
* driver.c - centralized device 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/string.h>
#include "base.h"
#define to_dev(node) container_of(node, struct device, driver_list)
static struct device *next_device(struct klist_iter *i)
{
struct klist_node *n = klist_next(i);
return n ? container_of(n, struct device, knode_driver) : NULL;
}
/**
* driver_for_each_device - Iterator for devices bound to a driver.
* @drv: Driver we're iterating.
* @start: Device to begin with
* @data: Data to pass to the callback.
* @fn: Function to call for each device.
*
* Iterate over the @drv's list of devices calling @fn for each one.
*/
int driver_for_each_device(struct device_driver *drv, struct device *start,
void *data, int (*fn)(struct device *, void *))
{
struct klist_iter i;
struct device *dev;
int error = 0;
if (!drv)
return -EINVAL;
klist_iter_init_node(&drv->p->klist_devices, &i,
start ? &start->knode_driver : NULL);
while ((dev = next_device(&i)) && !error)
error = fn(dev, data);
klist_iter_exit(&i);
return error;
}
EXPORT_SYMBOL_GPL(driver_for_each_device);
/**
* driver_find_device - device iterator for locating a particular device.
* @drv: The device's driver
* @start: Device to begin with
* @data: Data to pass to match function
* @match: Callback function to check device
*
* This is similar to the driver_for_each_device() 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 *driver_find_device(struct device_driver *drv,
struct device *start, void *data,
int (*match)(struct device *dev, void *data))
{
struct klist_iter i;
struct device *dev;
if (!drv)
return NULL;
klist_iter_init_node(&drv->p->klist_devices, &i,
(start ? &start->knode_driver : NULL));
while ((dev = next_device(&i)))
if (match(dev, data) && get_device(dev))
break;
klist_iter_exit(&i);
return dev;
}
EXPORT_SYMBOL_GPL(driver_find_device);
/**
* driver_create_file - create sysfs file for driver.
* @drv: driver.
* @attr: driver attribute descriptor.
*/
int driver_create_file(struct device_driver *drv,
struct driver_attribute *attr)
{
int error;
if (drv)
error = sysfs_create_file(&drv->p->kobj, &attr->attr);
else
error = -EINVAL;
return error;
}
EXPORT_SYMBOL_GPL(driver_create_file);
/**
* driver_remove_file - remove sysfs file for driver.
* @drv: driver.
* @attr: driver attribute descriptor.
*/
void driver_remove_file(struct device_driver *drv,
struct driver_attribute *attr)
{
if (drv)
sysfs_remove_file(&drv->p->kobj, &attr->attr);
}
EXPORT_SYMBOL_GPL(driver_remove_file);
/**
* driver_add_kobj - add a kobject below the specified driver
* @drv: requesting device driver
* @kobj: kobject to add below this driver
* @fmt: format string that names the kobject
*
* You really don't want to do this, this is only here due to one looney
* iseries driver, go poke those developers if you are annoyed about
* this...
*/
int driver_add_kobj(struct device_driver *drv, struct kobject *kobj,
const char *fmt, ...)
{
va_list args;
char *name;
int ret;
va_start(args, fmt);
name = kvasprintf(GFP_KERNEL, fmt, args);
va_end(args);
if (!name)
return -ENOMEM;
ret = kobject_add(kobj, &drv->p->kobj, "%s", name);
kfree(name);
return ret;
}
EXPORT_SYMBOL_GPL(driver_add_kobj);
/**
* get_driver - increment driver reference count.
* @drv: driver.
*/
struct device_driver *get_driver(struct device_driver *drv)
{
if (drv) {
struct driver_private *priv;
struct kobject *kobj;
kobj = kobject_get(&drv->p->kobj);
priv = to_driver(kobj);
return priv->driver;
}
return NULL;
}
EXPORT_SYMBOL_GPL(get_driver);
/**
* put_driver - decrement driver's refcount.
* @drv: driver.
*/
void put_driver(struct device_driver *drv)
{
kobject_put(&drv->p->kobj);
}
EXPORT_SYMBOL_GPL(put_driver);
static int driver_add_groups(struct device_driver *drv,
struct attribute_group **groups)
{
int error = 0;
int i;
if (groups) {
for (i = 0; groups[i]; i++) {
error = sysfs_create_group(&drv->p->kobj, groups[i]);
if (error) {
while (--i >= 0)
sysfs_remove_group(&drv->p->kobj,
groups[i]);
break;
}
}
}
return error;
}
static void driver_remove_groups(struct device_driver *drv,
struct attribute_group **groups)
{
int i;
if (groups)
for (i = 0; groups[i]; i++)
sysfs_remove_group(&drv->p->kobj, groups[i]);
}
/**
* driver_register - register driver with bus
* @drv: driver to register
*
* We pass off most of the work to the bus_add_driver() call,
* since most of the things we have to do deal with the bus
* structures.
*/
int driver_register(struct device_driver *drv)
{
int ret;
struct device_driver *other;
if ((drv->bus->probe && drv->probe) ||
(drv->bus->remove && drv->remove) ||
(drv->bus->shutdown && drv->shutdown))
printk(KERN_WARNING "Driver '%s' needs updating - please use "
"bus_type methods\n", drv->name);
other = driver_find(drv->name, drv->bus);
if (other) {
put_driver(other);
printk(KERN_ERR "Error: Driver '%s' is already registered, "
"aborting...\n", drv->name);
return -EEXIST;
}
ret = bus_add_driver(drv);
if (ret)
return ret;
ret = driver_add_groups(drv, drv->groups);
if (ret)
bus_remove_driver(drv);
return ret;
}
EXPORT_SYMBOL_GPL(driver_register);
/**
* driver_unregister - remove driver from system.
* @drv: driver.
*
* Again, we pass off most of the work to the bus-level call.
*/
void driver_unregister(struct device_driver *drv)
{
driver_remove_groups(drv, drv->groups);
bus_remove_driver(drv);
}
EXPORT_SYMBOL_GPL(driver_unregister);
/**
* driver_find - locate driver on a bus by its name.
* @name: name of the driver.
* @bus: bus to scan for the driver.
*
* Call kset_find_obj() to iterate over list of drivers on
* a bus to find driver by name. Return driver if found.
*
* Note that kset_find_obj increments driver's reference count.
*/
struct device_driver *driver_find(const char *name, struct bus_type *bus)
{
struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
struct driver_private *priv;
if (k) {
priv = to_driver(k);
return priv->driver;
}
return NULL;
}
EXPORT_SYMBOL_GPL(driver_find);