[PATCH 186/196] Driver core: Cleanup get_device_parent() in device_add() and device_move()

Greg Kroah-Hartman
2008-01-25T08:27:45Z

From: Cornelia Huck <cornelia.huck@de.ibm.com>

Make setup_parent() void as get_device_parent() will always return
either a valid kobject or NULL.
Introduce cleanup_glue_dir() to drop reference grabbed on "glue"
directory by get_device_parent(). Use it for cleanup in device_move()
and device_add() on errors.

This should fix the refcounting problem reported in
http://marc.info/?l=linux-kernel&m=120052487909200&w=2

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Dave Young <hidave.darkstar@gmail.com>
Cc: Gabor Gombas <gombasg@sztaki.hu>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: David Miller <davem@davemloft.net>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
drivers/base/core.c | 29 ++++++++++++++---------------
1 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index d5d542d..f09dde3 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -552,6 +552,8 @@ static struct kobject *get_device_parent(struct device *dev,
}

static inline void cleanup_device_parent(struct device *dev) {}
+static inline void cleanup_glue_dir(struct device *dev,
+ struct kobject *glue_dir) {}
#else
static struct kobject *virtual_device_parent(struct device *dev)
{
@@ -616,27 +618,27 @@ static struct kobject *get_device_parent(struct device *dev,
return NULL;
}

-static void cleanup_device_parent(struct device *dev)
+static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
{
- struct kobject *glue_dir = dev->kobj.parent;
-
/* see if we live in a "glue" directory */
if (!dev->class || glue_dir->kset != &dev->class->class_dirs)
return;

kobject_put(glue_dir);
}
+
+static void cleanup_device_parent(struct device *dev)
+{
+ cleanup_glue_dir(dev, dev->kobj.parent);
+}
#endif

-static int setup_parent(struct device *dev, struct device *parent)
+static void setup_parent(struct device *dev, struct device *parent)
{
struct kobject *kobj;
kobj = get_device_parent(dev, parent);
- if (IS_ERR(kobj))
- return PTR_ERR(kobj);
if (kobj)
dev->kobj.parent = kobj;
- return 0;
}

static int device_add_class_symlinks(struct device *dev)
@@ -784,9 +786,7 @@ int device_add(struct device *dev)
pr_debug("device: '%s': %s\n", dev->bus_id, __FUNCTION__);

parent = get_device(dev->parent);
- error = setup_parent(dev, parent);
- if (error)
- goto Error;
+ setup_parent(dev, parent);

/* first, register with generic layer. */
error = kobject_add(&dev->kobj, dev->kobj.parent, "%s", dev->bus_id);
@@ -864,6 +864,7 @@ int device_add(struct device *dev)
kobject_uevent(&dev->kobj, KOBJ_REMOVE);
kobject_del(&dev->kobj);
Error:
+ cleanup_device_parent(dev);
if (parent)
put_device(parent);
goto Done;
@@ -1344,15 +1345,12 @@ int device_move(struct device *dev, struct device *new_parent)

new_parent = get_device(new_parent);
new_parent_kobj = get_device_parent (dev, new_parent);
- if (IS_ERR(new_parent_kobj)) {
- error = PTR_ERR(new_parent_kobj);
- put_device(new_parent);
- goto out;
- }
+
pr_debug("device: '%s': %s: moving to '%s'\n", dev->bus_id,
__FUNCTION__, new_parent ? new_parent->bus_id : "<NULL>");
error = kobject_move(&dev->kobj, new_parent_kobj);
if (error) {
+ cleanup_glue_dir(dev, new_parent_kobj);
put_device(new_parent);
goto out;
}
@@ -1375,6 +1373,7 @@ int device_move(struct device *dev, struct device *new_parent)
klist_add_tail(&dev->knode_parent,
&old_parent->klist_children);
}
+ cleanup_glue_dir(dev, new_parent_kobj);
put_device(new_parent);
goto out;
}
--
1.5.3.8