driver core: fix namespace issue with devices assigned to classes

  - uses a kset in "struct class" to keep track of all directories
    belonging to this class
  - merges with the /sys/devices/virtual logic.
  - removes the namespace-dir if the last member of that class
    leaves the directory.

There may be locking or refcounting fixes left, I stopped when it seemed
to work with network and sound modules. :)

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

2 files changed, 3 insertions, 2 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index 5cf30e95c8b6..de0e73eae6bc 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -181,10 +181,9 @@ struct class {
         struct list_head        children;
         struct list_head        devices;
         struct list_head        interfaces;
+        struct kset             class_dirs;
         struct semaphore        sem;    /* locks both the children and interfaces lists */
 
-        struct kobject          *virtual_dir;
-
         struct class_attribute          * class_attrs;
         struct class_device_attribute   * class_dev_attrs;
         struct device_attribute         * dev_attrs;
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index b850e0310538..d37cd7f10e3d 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -89,6 +89,8 @@ extern void kobject_unregister(struct kobject *);
 extern struct kobject * kobject_get(struct kobject *);
 extern void kobject_put(struct kobject *);
 
+extern struct kobject *kobject_kset_add_dir(struct kset *kset,
+                                            struct kobject *, const char *);
 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
 
 extern char * kobject_get_path(struct kobject *, gfp_t);