driver core: Allow device_move(dev, NULL).

If we allow NULL as the new parent in device_move(), we need to make sure
that the device is placed into the same place as it would if it was
newly registered:

- Consider the device virtual tree. In order to be able to reuse code,
  setup_parent() has been tweaked a bit.
- kobject_move() can fall back to the kset's kobject.
- sysfs_move_dir() uses the sysfs root dir as fallback.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 36eedfdeb547aacb1c580b896366faa73201bd9c..c60114dbe5f5d7663770cfbc794a65f666f6f787 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -390,22 +390,23 @@ void device_initialize(struct device *dev)
 }
 
 #ifdef CONFIG_SYSFS_DEPRECATED
-static int setup_parent(struct device *dev, struct device *parent)
+static struct kobject * get_device_parent(struct device *dev,
+                                         struct device *parent)
 {
        /* Set the parent to the class, not the parent device */
        /* this keeps sysfs from having a symlink to make old udevs happy */
        if (dev->class)
-               dev->kobj.parent = &dev->class->subsys.kset.kobj;
+               return &dev->class->subsys.kset.kobj;
        else if (parent)
-               dev->kobj.parent = &parent->kobj;
+               return &parent->kobj;
 
-       return 0;
+       return NULL;
 }
 #else
-static int virtual_device_parent(struct device *dev)
+static struct kobject * virtual_device_parent(struct device *dev)
 {
        if (!dev->class)
-               return -ENODEV;
+               return ERR_PTR(-ENODEV);
 
        if (!dev->class->virtual_dir) {
                static struct kobject *virtual_dir = NULL;
@@ -415,25 +416,31 @@ static int virtual_device_parent(struct device *dev)
                dev->class->virtual_dir = kobject_add_dir(virtual_dir, dev->class->name);
        }
 
-       dev->kobj.parent = dev->class->virtual_dir;
-       return 0;
+       return dev->class->virtual_dir;
 }
 
-static int setup_parent(struct device *dev, struct device *parent)
+static struct kobject * get_device_parent(struct device *dev,
+                                         struct device *parent)
 {
-       int error;
-
        /* if this is a class device, and has no parent, create one */
        if ((dev->class) && (parent == NULL)) {
-               error = virtual_device_parent(dev);
-               if (error)
-                       return error;
+               return virtual_device_parent(dev);
        } else if (parent)
-               dev->kobj.parent = &parent->kobj;
+               return &parent->kobj;
+       return NULL;
+}
 
+#endif
+static int 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;
 }
-#endif
 
 /**
  *     device_add - add device to device hierarchy.
@@ -976,12 +983,18 @@ static int device_move_class_links(struct device *dev,
                sysfs_remove_link(&dev->kobj, "device");
                sysfs_remove_link(&old_parent->kobj, class_name);
        }
-       error = sysfs_create_link(&dev->kobj, &new_parent->kobj, "device");
-       if (error)
-               goto out;
-       error = sysfs_create_link(&new_parent->kobj, &dev->kobj, class_name);
-       if (error)
-               sysfs_remove_link(&dev->kobj, "device");
+       if (new_parent) {
+               error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
+                                         "device");
+               if (error)
+                       goto out;
+               error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
+                                         class_name);
+               if (error)
+                       sysfs_remove_link(&dev->kobj, "device");
+       }
+       else
+               error = 0;
 out:
        kfree(class_name);
        return error;
@@ -993,25 +1006,28 @@ out:
 /**
  * device_move - moves a device to a new parent
  * @dev: the pointer to the struct device to be moved
- * @new_parent: the new parent of the device
+ * @new_parent: the new parent of the device (can by NULL)
  */
 int device_move(struct device *dev, struct device *new_parent)
 {
        int error;
        struct device *old_parent;
+       struct kobject *new_parent_kobj;
 
        dev = get_device(dev);
        if (!dev)
                return -EINVAL;
 
        new_parent = get_device(new_parent);
-       if (!new_parent) {
-               error = -EINVAL;
+       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: moving '%s' to '%s'\n", dev->bus_id,
-               new_parent->bus_id);
-       error = kobject_move(&dev->kobj, &new_parent->kobj);
+                new_parent ? new_parent->bus_id : "<NULL>");
+       error = kobject_move(&dev->kobj, new_parent_kobj);
        if (error) {
                put_device(new_parent);
                goto out;
@@ -1020,7 +1036,8 @@ int device_move(struct device *dev, struct device *new_parent)
        dev->parent = new_parent;
        if (old_parent)
                klist_remove(&dev->knode_parent);
-       klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
+       if (new_parent)
+               klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
        if (!dev->class)
                goto out_put;
        error = device_move_class_links(dev, old_parent, new_parent);
@@ -1028,7 +1045,8 @@ int device_move(struct device *dev, struct device *new_parent)
                /* We ignore errors on cleanup since we're hosed anyway... */
                device_move_class_links(dev, new_parent, old_parent);
                if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
-                       klist_remove(&dev->knode_parent);
+                       if (new_parent)
+                               klist_remove(&dev->knode_parent);
                        if (old_parent)
                                klist_add_tail(&dev->knode_parent,
                                               &old_parent->klist_children);

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 511edef8b321a99c8ba4a45ee8e70515d6d3d61b..2bab1b4ddf5ae506b0080157380dfed1edbfda4b 100644 (file)
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -378,12 +378,10 @@ int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)
        struct sysfs_dirent *new_parent_sd, *sd;
        int error;
 
-       if (!new_parent)
-               return -EINVAL;
-
        old_parent_dentry = kobj->parent ?
                kobj->parent->dentry : sysfs_mount->mnt_sb->s_root;
-       new_parent_dentry = new_parent->dentry;
+       new_parent_dentry = new_parent ?
+               new_parent->dentry : sysfs_mount->mnt_sb->s_root;
 
 again:
        mutex_lock(&old_parent_dentry->d_inode->i_mutex);

diff --git a/lib/kobject.c b/lib/kobject.c
index 9aed594bfcac414b03a78413a4367a5cb70714e9..c033dc8fa9af8ad784605aa6acd5fd85cdca7277 100644 (file)
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -314,7 +314,7 @@ int kobject_rename(struct kobject * kobj, const char *new_name)
 /**
  *     kobject_move - move object to another parent
  *     @kobj:  object in question.
- *     @new_parent: object's new parent
+ *     @new_parent: object's new parent (can be NULL)
  */
 
 int kobject_move(struct kobject *kobj, struct kobject *new_parent)
@@ -330,8 +330,8 @@ int kobject_move(struct kobject *kobj, struct kobject *new_parent)
                return -EINVAL;
        new_parent = kobject_get(new_parent);
        if (!new_parent) {
-               error = -EINVAL;
-               goto out;
+               if (kobj->kset)
+                       new_parent = kobject_get(&kobj->kset->kobj);
        }
        /* old object path */
        devpath = kobject_get_path(kobj, GFP_KERNEL);