From foo@baz Tue Apr  9 12:12:43 2002
To: Greg KH <gregkh@suse.de>
Date: 24 Mar 2005 13:02:28 -08:00
From: mochel@digitalimplant.org
Subject: [driver core] Fix up bus code and remove use of rwsem.

- Don't add devices to bus's embedded kset, since it's not used by anyone anymore.
- Don't need to take the bus rwsem when calling {device,driver}_attach(), since
  those functions use the klists and the klists' spinlocks.


Signed-off-by: Patrick Mochel <mochel@digitalimplant.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>


diff -Nru a/drivers/base/bus.c b/drivers/base/bus.c
--- a/drivers/base/bus.c	2005-04-05 10:52:10 -07:00
+++ b/drivers/base/bus.c	2005-04-05 10:52:10 -07:00
@@ -17,8 +17,6 @@
 #include "base.h"
 #include "power/power.h"
 
-#define to_dev(node) container_of(node, struct device, bus_list)
-
 #define to_bus_attr(_attr) container_of(_attr, struct bus_attribute, attr)
 #define to_bus(obj) container_of(obj, struct bus_type, subsys.kset.kobj)
 
@@ -272,11 +270,8 @@
 	int error = 0;
 
 	if (bus) {
-		down_write(&dev->bus->subsys.rwsem);
 		pr_debug("bus %s: add device %s\n", bus->name, dev->bus_id);
-		list_add_tail(&dev->bus_list, &dev->bus->devices.list);
 		device_attach(dev);
-		up_write(&dev->bus->subsys.rwsem);
 		klist_add_tail(&bus->klist_devices, &dev->knode_bus);
 		device_add_attrs(bus, dev);
 		sysfs_create_link(&bus->devices.kobj, &dev->kobj, dev->bus_id);
@@ -301,11 +296,8 @@
 		sysfs_remove_link(&dev->bus->devices.kobj, dev->bus_id);
 		device_remove_attrs(dev->bus, dev);
 		klist_remove(&dev->knode_bus);
-		down_write(&dev->bus->subsys.rwsem);
 		pr_debug("bus %s: remove device %s\n", dev->bus->name, dev->bus_id);
 		device_release_driver(dev);
-		list_del_init(&dev->bus_list);
-		up_write(&dev->bus->subsys.rwsem);
 		put_bus(dev->bus);
 	}
 }
@@ -365,9 +357,7 @@
 			return error;
 		}
 
-		down_write(&bus->subsys.rwsem);
 		driver_attach(drv);
-		up_write(&bus->subsys.rwsem);
 		klist_add_tail(&bus->klist_drivers, &drv->knode_bus);
 		module_add_driver(drv->owner, drv);
 
@@ -391,10 +381,8 @@
 	if (drv->bus) {
 		driver_remove_attrs(drv->bus, drv);
 		klist_remove(&drv->knode_bus);
-		down_write(&drv->bus->subsys.rwsem);
 		pr_debug("bus %s: remove driver %s\n", drv->bus->name, drv->name);
 		driver_detach(drv);
-		up_write(&drv->bus->subsys.rwsem);
 		module_remove_driver(drv);
 		kobject_unregister(&drv->kobj);
 		put_bus(drv->bus);