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Commit 94e7b1c5 authored by Patrick Mochel's avatar Patrick Mochel Committed by Greg Kroah-Hartman
Browse files

[PATCH] Add a klist to struct device_driver for the devices bound to it. 



- Use it in driver_for_each_device() instead of the regular list_head and stop using
  the bus's rwsem for protection.
- Use driver_for_each_device() in driver_detach() so we don't deadlock on the
  bus's rwsem.
- Remove ->devices.
- Move klist access and sysfs link access out from under device's semaphore, since
  they're synchronized through other means.

Signed-off-by: default avatarPatrick Mochel <mochel@digitalimplant.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 38fdac3c

drivers/base/core.c

+1 −1
Original line number Diff line number Diff line
@@ -209,8 +209,8 @@ void device_initialize(struct device *dev) 
	kobject_init(&dev->kobj);

	INIT_LIST_HEAD(&dev->node);

	INIT_LIST_HEAD(&dev->children);

	INIT_LIST_HEAD(&dev->driver_list);

	INIT_LIST_HEAD(&dev->bus_list);

	INIT_LIST_HEAD(&dev->driver_list);

	INIT_LIST_HEAD(&dev->dma_pools);

	init_MUTEX(&dev->sem);

}

drivers/base/dd.c

+19 −15
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ void device_bind_driver(struct device * dev) 
{

	pr_debug("bound device '%s' to driver '%s'\n",

		 dev->bus_id, dev->driver->name);

	list_add_tail(&dev->driver_list, &dev->driver->devices);

	klist_add_tail(&dev->driver->klist_devices, &dev->knode_driver);

	sysfs_create_link(&dev->driver->kobj, &dev->kobj,

			  kobject_name(&dev->kobj));

	sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver");
@@ -164,31 +164,35 @@ void driver_attach(struct device_driver * drv) 
 */

void device_release_driver(struct device * dev)

{

	struct device_driver * drv;

	struct device_driver * drv = dev->driver;



	if (!drv)

		return;



	down(&dev->sem);

	drv = dev->driver;

	if (drv) {

	sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));

	sysfs_remove_link(&dev->kobj, "driver");

		list_del_init(&dev->driver_list);

	klist_remove(&dev->knode_driver);



	down(&dev->sem);

	if (drv->remove)

		drv->remove(dev);

	dev->driver = NULL;

	}

	up(&dev->sem);

}



static int __remove_driver(struct device * dev, void * unused)

{

	device_release_driver(dev);

	return 0;

}



/**

 * driver_detach - detach driver from all devices it controls.

 * @drv: driver.

 */

void driver_detach(struct device_driver * drv)

{

	while (!list_empty(&drv->devices)) {

		struct device * dev = container_of(drv->devices.next, struct device, driver_list);

		device_release_driver(dev);

	}

	driver_for_each_device(drv, NULL, NULL, __remove_driver);

}

drivers/base/driver.c

+15 −12
Original line number Diff line number Diff line
@@ -19,6 +19,12 @@ 
#define to_drv(obj) container_of(obj, struct device_driver, kobj)





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.
@@ -32,21 +38,18 @@ 
int driver_for_each_device(struct device_driver * drv, struct device * start, 

			   void * data, int (*fn)(struct device *, void *))

{

	struct list_head * head;

	struct klist_iter i;

	struct device * dev;

	int error = 0;



	down_read(&drv->bus->subsys.rwsem);

	head = &drv->devices;

	dev = list_prepare_entry(start, head, driver_list);

	list_for_each_entry_continue(dev, head, driver_list) {

		get_device(dev);

	if (!drv)

		return -EINVAL;



	klist_iter_init_node(&drv->klist_devices, &i,

			     start ? &start->knode_driver : NULL);

	while ((dev = next_device(&i)) && !error)

		error = fn(dev, data);

		put_device(dev);

		if (error)

			break;

	}

	up_read(&drv->bus->subsys.rwsem);

	klist_iter_exit(&i);

	return error;

}
@@ -120,7 +123,7 @@ void put_driver(struct device_driver * drv) 
 */

int driver_register(struct device_driver * drv)

{

	INIT_LIST_HEAD(&drv->devices);

	klist_init(&drv->klist_devices);

	init_completion(&drv->unloaded);

	return bus_add_driver(drv);

}

include/linux/device.h

+2 −1
Original line number Diff line number Diff line
@@ -105,7 +105,7 @@ struct device_driver { 


	struct completion	unloaded;

	struct kobject		kobj;

	struct list_head	devices;

	struct klist		klist_devices;

	struct klist_node	knode_bus;



	struct module		* owner;
@@ -266,6 +266,7 @@ struct device { 
	struct list_head bus_list;	/* node in bus's list */

	struct list_head driver_list;

	struct list_head children;

	struct klist_node	knode_driver;

	struct klist_node	knode_bus;

	struct device 	* parent;