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Commit 5739411a authored by Cornelia Huck's avatar Cornelia Huck Committed by Greg Kroah-Hartman
Browse files

Driver core: Clarify device cleanup. 



Make the comments on how to use device_initialize(), device_add()
and device_register() a bit clearer - in particular, explicitly
note that put_device() must be used once we tried to add the device
to the hierarchy.

Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Cc: stable <stable@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 9cf899d1

drivers/base/core.c

+18 −5
Original line number Diff line number Diff line
@@ -523,11 +523,16 @@ static void klist_children_put(struct klist_node *n) 
 * device_initialize - init device structure.

 * @dev: device.

 *

 * This prepares the device for use by other layers,

 * including adding it to the device hierarchy.

 * This prepares the device for use by other layers by initializing

 * its fields.

 * It is the first half of device_register(), if called by

 * that, though it can also be called separately, so one

 * may use @dev's fields (e.g. the refcount).

 * that function, though it can also be called separately, so one

 * may use @dev's fields. In particular, get_device()/put_device()

 * may be used for reference counting of @dev after calling this

 * function.

 *

 * NOTE: Use put_device() to give up your reference instead of freeing

 * @dev directly once you have called this function.

 */

void device_initialize(struct device *dev)

{
@@ -835,9 +840,13 @@ static void device_remove_sys_dev_entry(struct device *dev) 
 * This is part 2 of device_register(), though may be called

 * separately _iff_ device_initialize() has been called separately.

 *

 * This adds it to the kobject hierarchy via kobject_add(), adds it

 * This adds @dev to the kobject hierarchy via kobject_add(), adds it

 * to the global and sibling lists for the device, then

 * adds it to the other relevant subsystems of the driver model.

 *

 * NOTE: _Never_ directly free @dev after calling this function, even

 * if it returned an error! Always use put_device() to give up your

 * reference instead.

 */

int device_add(struct device *dev)

{
@@ -965,6 +974,10 @@ int device_add(struct device *dev) 
 * I.e. you should only call the two helpers separately if

 * have a clearly defined need to use and refcount the device

 * before it is added to the hierarchy.

 *

 * NOTE: _Never_ directly free @dev after calling this function, even

 * if it returned an error! Always use put_device() to give up the

 * reference initialized in this function instead.

 */

int device_register(struct device *dev)

{