driver core: create a private portion of struct device

This is to be used to move things out of struct device that no code
outside of the driver core should ever touch.

Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 23 insertions, 0 deletions

diff --git a/drivers/base/base.h b/drivers/base/base.h
index 0a5f055dffba..6b20809b5fd4 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -63,6 +63,18 @@ struct class_private {
 #define to_class(obj)   \
         container_of(obj, struct class_private, class_subsys.kobj)
 
+/**
+ * struct device_private - structure to hold the private to the driver core portions of the device structure.
+ *
+ * @device - pointer back to the struct class that this structure is
+ * associated with.
+ *
+ * Nothing outside of the driver core should ever touch these fields.
+ */
+struct device_private {
+        struct device *device;
+};
+
 /* initialisation functions */
 extern int devices_init(void);
 extern int buses_init(void);
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 14aa2b6953c9..6657787e64f8 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -109,6 +109,7 @@ static struct sysfs_ops dev_sysfs_ops = {
 static void device_release(struct kobject *kobj)
 {
         struct device *dev = to_dev(kobj);
+        struct device_private *p = dev->p;
 
         if (dev->release)
                 dev->release(dev);
@@ -120,6 +121,7 @@ static void device_release(struct kobject *kobj)
                 WARN(1, KERN_ERR "Device '%s' does not have a release() "
                         "function, it is broken and must be fixed.\n",
                         dev_name(dev));
+        kfree(p);
 }
 
 static struct kobj_type device_ktype = {
@@ -536,6 +538,12 @@ static void klist_children_put(struct klist_node *n)
  */
 void device_initialize(struct device *dev)
 {
+        dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
+        if (!dev->p) {
+                WARN_ON(1);
+                return;
+        }
+        dev->p->device = dev;
         dev->kobj.kset = devices_kset;
         kobject_init(&dev->kobj, &device_ktype);
         klist_init(&dev->klist_children, klist_children_get,
diff --git a/include/linux/device.h b/include/linux/device.h
index 4e14fad41430..d6d34084fd37 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -28,6 +28,7 @@
 #define BUS_ID_SIZE             20
 
 struct device;
+struct device_private;
 struct device_driver;
 struct driver_private;
 struct class;
@@ -371,6 +372,8 @@ struct device {
         struct klist_node       knode_bus;
         struct device           *parent;
 
+        struct device_private   *p;
+
         struct kobject kobj;
         char    bus_id[BUS_ID_SIZE];    /* position on parent bus */
         unsigned                uevent_suppress:1;