From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755516AbYJPRZR (ORCPT ); Thu, 16 Oct 2008 13:25:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756357AbYJPROp (ORCPT ); Thu, 16 Oct 2008 13:14:45 -0400 Received: from kroah.org ([198.145.64.141]:46990 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756335AbYJPROo (ORCPT ); Thu, 16 Oct 2008 13:14:44 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Cornelia Huck , stable , Greg Kroah-Hartman Subject: [PATCH 27/46] Driver core: Clarify device cleanup. Date: Thu, 16 Oct 2008 10:10:28 -0700 Message-Id: <1224177047-11859-27-git-send-email-gregkh@suse.de> X-Mailer: git-send-email 1.6.0.2 In-Reply-To: <20081016170954.GA11824@kroah.com> References: <20081016170954.GA11824@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Cornelia Huck 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 Cc: stable Signed-off-by: Greg Kroah-Hartman --- 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 b98cb14..aac91e8 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) { -- 1.6.0.2