diff options
author | Cornelia Huck <cornelia.huck@de.ibm.com> | 2008-09-03 20:26:40 +0400 |
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committer | Greg Kroah-Hartman <gregkh@suse.de> | 2008-10-16 20:24:48 +0400 |
commit | 5739411acbaa63a6c22c91e340fdcdbcc7d82a51 (patch) | |
tree | 1f54912f36211076a341067395599ec449bc1ae5 /drivers/base/core.c | |
parent | 9cf899d12583082c77a0fcc758f3179b440518ee (diff) | |
download | linux-5739411acbaa63a6c22c91e340fdcdbcc7d82a51.tar.xz |
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: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/base/core.c')
-rw-r--r-- | drivers/base/core.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index b98cb1416a2d..aac91e89d6af 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -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 @@ done: * 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) { |