[PATCH 27/47] Driver core: allow devices in classes to have no parent

From: Greg Kroah-Hartman <gregkh@xxxxxxx>

This fixes an oops when a device is attached to a class, yet has no
"parent" device. An example of this would be the "lo" device in the
network core.

We should create a "virtual" subdirectory under /sys/devices/ for these,
but no one seems to agree on a proper name for it yet...

Oh, and update my copyright on the driver core.

Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
drivers/base/core.c | 21 +++++++++++----------
1 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 641c0c4..5c91d0d 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3,6 +3,8 @@
*
* Copyright (c) 2002-3 Patrick Mochel
* Copyright (c) 2002-3 Open Source Development Labs
+ * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@xxxxxxx>
+ * Copyright (c) 2006 Novell, Inc.
*
* This file is released under the GPLv2
*
@@ -373,10 +375,11 @@ int device_add(struct device *dev)
"subsystem");
sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
dev->bus_id);
-
- sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device");
- class_name = make_class_name(dev->class->name, &dev->kobj);
- sysfs_create_link(&dev->parent->kobj, &dev->kobj, class_name);
+ if (parent) {
+ sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device");
+ class_name = make_class_name(dev->class->name, &dev->kobj);
+ sysfs_create_link(&dev->parent->kobj, &dev->kobj, class_name);
+ }
}

if ((error = device_add_groups(dev)))
@@ -495,8 +498,10 @@ void device_del(struct device * dev)
sysfs_remove_link(&dev->kobj, "subsystem");
sysfs_remove_link(&dev->class->subsys.kset.kobj, dev->bus_id);
class_name = make_class_name(dev->class->name, &dev->kobj);
- sysfs_remove_link(&dev->kobj, "device");
- sysfs_remove_link(&dev->parent->kobj, class_name);
+ if (parent) {
+ sysfs_remove_link(&dev->kobj, "device");
+ sysfs_remove_link(&dev->parent->kobj, class_name);
+ }
kfree(class_name);
down(&dev->class->sem);
list_del_init(&dev->node);
@@ -625,10 +630,6 @@ struct device *device_create(struct clas

if (class == NULL || IS_ERR(class))
goto error;
- if (parent == NULL) {
- printk(KERN_WARNING "%s does not work yet for NULL parents\n", __FUNCTION__);
- goto error;
- }

dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev) {
--
1.4.2.1

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