[PATCH] Use a klist for device child lists.

- Use klist iterator in device_for_each_child(), making it safe to use for
  removing devices.
- Remove unused list_to_dev() function.
- Kills all usage of devices_subsys.rwsem.

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 bfa4268..1d8c779 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -207,8 +207,7 @@ void device_initialize(struct device *dev)
 {
        kobj_set_kset_s(dev, devices_subsys);
        kobject_init(&dev->kobj);
-       INIT_LIST_HEAD(&dev->node);
-       INIT_LIST_HEAD(&dev->children);
+       klist_init(&dev->klist_children);
        INIT_LIST_HEAD(&dev->dma_pools);
        init_MUTEX(&dev->sem);
 }
@@ -249,10 +248,8 @@ int device_add(struct device *dev)
                goto PMError;
        if ((error = bus_add_device(dev)))
                goto BusError;
-       down_write(&devices_subsys.rwsem);
        if (parent)
-               list_add_tail(&dev->node, &parent->children);
-       up_write(&devices_subsys.rwsem);
+               klist_add_tail(&parent->klist_children, &dev->knode_parent);
 
        /* notify platform of device entry */
        if (platform_notify)
@@ -335,10 +332,8 @@ void device_del(struct device * dev)
 {
        struct device * parent = dev->parent;
 
-       down_write(&devices_subsys.rwsem);
        if (parent)
-               list_del_init(&dev->node);
-       up_write(&devices_subsys.rwsem);
+               klist_remove(&dev->knode_parent);
 
        /* Notify the platform of the removal, in case they
         * need to do anything...
@@ -372,6 +367,12 @@ void device_unregister(struct device * dev)
 }
 
 
+static struct device * next_device(struct klist_iter * i)
+{
+       struct klist_node * n = klist_next(i);
+       return n ? container_of(n, struct device, knode_parent) : NULL;
+}
+
 /**
  *     device_for_each_child - device child iterator.
  *     @dev:   parent struct device.
@@ -384,18 +385,17 @@ void device_unregister(struct device * dev)
  *     We check the return of @fn each time. If it returns anything
  *     other than 0, we break out and return that value.
  */
-int device_for_each_child(struct device * dev, void * data,
+int device_for_each_child(struct device * parent, void * data,
                     int (*fn)(struct device *, void *))
 {
+       struct klist_iter i;
        struct device * child;
        int error = 0;
 
-       down_read(&devices_subsys.rwsem);
-       list_for_each_entry(child, &dev->children, node) {
-               if((error = fn(child, data)))
-                       break;
-       }
-       up_read(&devices_subsys.rwsem);
+       klist_iter_init(&parent->klist_children, &i);
+       while ((child = next_device(&i)) && !error)
+               error = fn(child, data);
+       klist_iter_exit(&i);
        return error;
 }
 

diff --git a/include/linux/device.h b/include/linux/device.h
index d243493..4324926 100644 (file)
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -262,8 +262,8 @@ extern void class_device_destroy(struct class *cls, dev_t devt);
 
 
 struct device {
-       struct list_head node;          /* node in sibling list */
-       struct list_head children;
+       struct klist            klist_children;
+       struct klist_node       knode_parent;           /* node in sibling list */
        struct klist_node       knode_driver;
        struct klist_node       knode_bus;
        struct device   * parent;
@@ -298,12 +298,6 @@ struct device {
        void    (*release)(struct device * dev);
 };
 
-static inline struct device *
-list_to_dev(struct list_head *node)
-{
-       return list_entry(node, struct device, node);
-}
-
 static inline void *
 dev_get_drvdata (struct device *dev)
 {