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>
diff --git a/drivers/base/core.c b/drivers/base/core.c
index db3a151..658eae5 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -477,34 +477,58 @@
return NULL;
}
#else
-static struct kobject * virtual_device_parent(struct device *dev)
+static struct kobject *virtual_device_parent(struct device *dev)
{
- if (!dev->class)
- return ERR_PTR(-ENODEV);
+ static struct kobject *virtual_dir = NULL;
- if (!dev->class->virtual_dir) {
- static struct kobject *virtual_dir = NULL;
+ if (!virtual_dir)
+ virtual_dir = kobject_add_dir(&devices_subsys.kset.kobj, "virtual");
- if (!virtual_dir)
- virtual_dir = kobject_add_dir(&devices_subsys.kset.kobj, "virtual");
- dev->class->virtual_dir = kobject_add_dir(virtual_dir, dev->class->name);
- }
-
- return dev->class->virtual_dir;
+ return virtual_dir;
}
static struct kobject * get_device_parent(struct device *dev,
struct device *parent)
{
- /* if this is a class device, and has no parent, create one */
- if ((dev->class) && (parent == NULL)) {
- return virtual_device_parent(dev);
- } else if (parent)
+ if (dev->class) {
+ struct kobject *kobj = NULL;
+ struct kobject *parent_kobj;
+ struct kobject *k;
+
+ /*
+ * If we have no parent, we live in "virtual".
+ * Class-devices with a bus-device as parent, live
+ * in a class-directory to prevent namespace collisions.
+ */
+ if (parent == NULL)
+ parent_kobj = virtual_device_parent(dev);
+ else if (parent->class)
+ return &parent->kobj;
+ else
+ parent_kobj = &parent->kobj;
+
+ /* find our class-directory at the parent and reference it */
+ spin_lock(&dev->class->class_dirs.list_lock);
+ list_for_each_entry(k, &dev->class->class_dirs.list, entry)
+ if (k->parent == parent_kobj) {
+ kobj = kobject_get(k);
+ break;
+ }
+ spin_unlock(&dev->class->class_dirs.list_lock);
+ if (kobj)
+ return kobj;
+
+ /* or create a new class-directory at the parent device */
+ return kobject_kset_add_dir(&dev->class->class_dirs,
+ parent_kobj, dev->class->name);
+ }
+
+ if (parent)
return &parent->kobj;
return NULL;
}
-
#endif
+
static int setup_parent(struct device *dev, struct device *parent)
{
struct kobject *kobj;
@@ -541,7 +565,6 @@
pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
parent = get_device(dev->parent);
-
error = setup_parent(dev, parent);
if (error)
goto Error;
@@ -787,6 +810,31 @@
/* remove the device from the class list */
list_del_init(&dev->node);
up(&dev->class->sem);
+
+ /* If we live in a parent class-directory, unreference it */
+ if (dev->kobj.parent->kset == &dev->class->class_dirs) {
+ struct device *d;
+ int other = 0;
+
+ /*
+ * if we are the last child of our class, delete
+ * our class-directory at this parent
+ */
+ down(&dev->class->sem);
+ list_for_each_entry(d, &dev->class->devices, node) {
+ if (d == dev)
+ continue;
+ if (d->kobj.parent == dev->kobj.parent) {
+ other = 1;
+ break;
+ }
+ }
+ if (!other)
+ kobject_del(dev->kobj.parent);
+
+ kobject_put(dev->kobj.parent);
+ up(&dev->class->sem);
+ }
}
device_remove_file(dev, &dev->uevent_attr);
device_remove_groups(dev);