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

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 9344082..bc5bec6 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -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);
 }

diff --git a/drivers/base/dd.c b/drivers/base/dd.c
index b709b1e..47cbb56 100644 (file)
--- a/drivers/base/dd.c
+++ b/drivers/base/dd.c
@@ -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;
+
+       sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
+       sysfs_remove_link(&dev->kobj, "driver");
+       klist_remove(&dev->knode_driver);
 
        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);
-               if (drv->remove)
-                       drv->remove(dev);
-               dev->driver = NULL;
-       }
+       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);
 }
 
 

diff --git a/drivers/base/driver.c b/drivers/base/driver.c
index 484fed1..34bd38a 100644 (file)
--- a/drivers/base/driver.c
+++ b/drivers/base/driver.c
@@ -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);
 }

diff --git a/include/linux/device.h b/include/linux/device.h
index ea9ab33..96c71b5 100644 (file)
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -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;