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, 20 insertions, 8 deletions

diff --git a/lib/kobject.c b/lib/kobject.c
index 057921c5945..f6645515560 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -488,13 +488,15 @@ static struct kobj_type dir_ktype = {
 };
 
 /**
- *	kobject_add_dir - add sub directory of object.
+ *	kobject__kset_add_dir - add sub directory of object.
+ *	@kset:		kset the directory is belongs to.
  *	@parent:	object in which a directory is created.
  *	@name:	directory name.
  *
  *	Add a plain directory object as child of given object.
  */
-struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
+struct kobject *kobject_kset_add_dir(struct kset *kset,
+				     struct kobject *parent, const char *name)
 {
 	struct kobject *k;
 	int ret;
@@ -506,6 +508,7 @@ struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
 	if (!k)
 		return NULL;
 
+	k->kset = kset;
 	k->parent = parent;
 	k->ktype = &dir_ktype;
 	kobject_set_name(k, name);
@@ -520,6 +523,11 @@ struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
 	return k;
 }
 
+struct kobject *kobject_add_dir(struct kobject *parent, const char *name)
+{
+	return kobject_kset_add_dir(NULL, parent, name);
+}
+
 /**
  *	kset_init - initialize a kset for use
  *	@k:	kset 
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index 82fc1794b69..4122f38330d 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -115,6 +115,16 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 			return 0;
 		}
 
+	/* originating subsystem */
+	if (uevent_ops && uevent_ops->name)
+		subsystem = uevent_ops->name(kset, kobj);
+	else
+		subsystem = kobject_name(&kset->kobj);
+	if (!subsystem) {
+		pr_debug("unset subsytem caused the event to drop!\n");
+		return 0;
+	}
+
 	/* environment index */
 	envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
 	if (!envp)
@@ -134,12 +144,6 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 		goto exit;
 	}
 
-	/* originating subsystem */
-	if (uevent_ops && uevent_ops->name)
-		subsystem = uevent_ops->name(kset, kobj);
-	else
-		subsystem = kobject_name(&kset->kobj);
-
 	/* event environemnt for helper process only */
 	envp[i++] = "HOME=/";
 	envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";