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Commit 8a82472f authored by Cornelia Huck's avatar Cornelia Huck Committed by Greg Kroah-Hartman
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driver core: Introduce device_move(): move a device to a new parent. 



Provide a function device_move() to move a device to a new parent device. Add
auxilliary functions kobject_move() and sysfs_move_dir().
kobject_move() generates a new uevent of type KOBJ_MOVE, containing the
previous path (DEVPATH_OLD) in addition to the usual values. For this, a new
interface kobject_uevent_env() is created that allows to add further
environmental data to the uevent at the kobject layer.

Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: default avatarKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent af9e0765

drivers/base/core.c

+92 −0
Original line number Diff line number Diff line
@@ -955,3 +955,95 @@ int device_rename(struct device *dev, char *new_name) 


	return error;

}





static int device_move_class_links(struct device *dev,

				   struct device *old_parent,

				   struct device *new_parent)

{

#ifdef CONFIG_SYSFS_DEPRECATED

	int error;

	char *class_name;



	class_name = make_class_name(dev->class->name, &dev->kobj);

	if (!class_name) {

		error = PTR_ERR(class_name);

		class_name = NULL;

		goto out;

	}

	if (old_parent) {

		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");

out:

	kfree(class_name);

	return error;

#else

	return 0;

#endif

}



/**

 * 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

 */

int device_move(struct device *dev, struct device *new_parent)

{

	int error;

	struct device *old_parent;



	dev = get_device(dev);

	if (!dev)

		return -EINVAL;



	if (!device_is_registered(dev)) {

		error = -EINVAL;

		goto out;

	}

	new_parent = get_device(new_parent);

	if (!new_parent) {

		error = -EINVAL;

		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);

	if (error) {

		put_device(new_parent);

		goto out;

	}

	old_parent = dev->parent;

	dev->parent = new_parent;

	if (old_parent)

		klist_del(&dev->knode_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);

	if (error) {

		/* 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_del(&dev->knode_parent);

			if (old_parent)

				klist_add_tail(&dev->knode_parent,

					       &old_parent->klist_children);

		}

		put_device(new_parent);

		goto out;

	}

out_put:

	put_device(old_parent);

out:

	put_device(dev);

	return error;

}



EXPORT_SYMBOL_GPL(device_move);

fs/sysfs/dir.c

+45 −0
Original line number Diff line number Diff line
@@ -372,6 +372,51 @@ int sysfs_rename_dir(struct kobject * kobj, const char *new_name) 
	return error;

}



int sysfs_move_dir(struct kobject *kobj, struct kobject *new_parent)

{

	struct dentry *old_parent_dentry, *new_parent_dentry, *new_dentry;

	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;



again:

	mutex_lock(&old_parent_dentry->d_inode->i_mutex);

	if (!mutex_trylock(&new_parent_dentry->d_inode->i_mutex)) {

		mutex_unlock(&old_parent_dentry->d_inode->i_mutex);

		goto again;

	}



	new_parent_sd = new_parent_dentry->d_fsdata;

	sd = kobj->dentry->d_fsdata;



	new_dentry = lookup_one_len(kobj->name, new_parent_dentry,

				    strlen(kobj->name));

	if (IS_ERR(new_dentry)) {

		error = PTR_ERR(new_dentry);

		goto out;

	} else

		error = 0;

	d_add(new_dentry, NULL);

	d_move(kobj->dentry, new_dentry);

	dput(new_dentry);



	/* Remove from old parent's list and insert into new parent's list. */

	list_del_init(&sd->s_sibling);

	list_add(&sd->s_sibling, &new_parent_sd->s_children);



out:

	mutex_unlock(&new_parent_dentry->d_inode->i_mutex);

	mutex_unlock(&old_parent_dentry->d_inode->i_mutex);



	return error;

}



static int sysfs_dir_open(struct inode *inode, struct file *file)

{

	struct dentry * dentry = file->f_dentry;

include/linux/device.h

+1 −0
Original line number Diff line number Diff line
@@ -424,6 +424,7 @@ extern int device_for_each_child(struct device *, void *, 
extern struct device *device_find_child(struct device *, void *data,

					int (*match)(struct device *, void *));

extern int device_rename(struct device *dev, char *new_name);

extern int device_move(struct device *dev, struct device *new_parent);



/*

 * Manual binding of a device to driver. See drivers/base/bus.c

include/linux/kobject.h

+8 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ enum kobject_action { 
	KOBJ_UMOUNT	= (__force kobject_action_t) 0x05,	/* umount event for block devices (broken) */

	KOBJ_OFFLINE	= (__force kobject_action_t) 0x06,	/* device offline */

	KOBJ_ONLINE	= (__force kobject_action_t) 0x07,	/* device online */

	KOBJ_MOVE	= (__force kobject_action_t) 0x08,	/* device move */

};



struct kobject {
@@ -76,6 +77,7 @@ extern int __must_check kobject_add(struct kobject *); 
extern void kobject_del(struct kobject *);



extern int __must_check kobject_rename(struct kobject *, const char *new_name);

extern int __must_check kobject_move(struct kobject *, struct kobject *);



extern int __must_check kobject_register(struct kobject *);

extern void kobject_unregister(struct kobject *);
@@ -264,6 +266,8 @@ extern int __must_check subsys_create_file(struct subsystem * , 


#if defined(CONFIG_HOTPLUG)

void kobject_uevent(struct kobject *kobj, enum kobject_action action);

void kobject_uevent_env(struct kobject *kobj, enum kobject_action action,

			char *envp[]);



int add_uevent_var(char **envp, int num_envp, int *cur_index,

			char *buffer, int buffer_size, int *cur_len,
@@ -271,6 +275,10 @@ int add_uevent_var(char **envp, int num_envp, int *cur_index, 
	__attribute__((format (printf, 7, 8)));

#else

static inline void kobject_uevent(struct kobject *kobj, enum kobject_action action) { }

static inline void kobject_uevent_env(struct kobject *kobj,

				      enum kobject_action action,

				      char *envp[])

{ }



static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,

				      char *buffer, int buffer_size, int *cur_len,

include/linux/sysfs.h

+8 −0
Original line number Diff line number Diff line
@@ -96,6 +96,9 @@ sysfs_remove_dir(struct kobject *); 
extern int __must_check

sysfs_rename_dir(struct kobject *, const char *new_name);



extern int __must_check

sysfs_move_dir(struct kobject *, struct kobject *);



extern int __must_check

sysfs_create_file(struct kobject *, const struct attribute *);
@@ -142,6 +145,11 @@ static inline int sysfs_rename_dir(struct kobject * k, const char *new_name) 
	return 0;

}



static inline int sysfs_move_dir(struct kobject * k, struct kobject * new_parent)

{

	return 0;

}



static inline int sysfs_create_file(struct kobject * k, const struct attribute * a)

{

	return 0;