From patchwork Mon Jun 1 14:47:59 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Shevchenko X-Patchwork-Id: 6522811 Return-Path: X-Original-To: patchwork-dmaengine@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 902E2C0433 for ; Mon, 1 Jun 2015 14:50:34 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A3E872043C for ; Mon, 1 Jun 2015 14:50:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A5417204A0 for ; Mon, 1 Jun 2015 14:50:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753166AbbFAOs0 (ORCPT ); Mon, 1 Jun 2015 10:48:26 -0400 Received: from mga11.intel.com ([192.55.52.93]:47572 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752864AbbFAOsQ (ORCPT ); Mon, 1 Jun 2015 10:48:16 -0400 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP; 01 Jun 2015 07:48:15 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,533,1427785200"; d="scan'208";a="734962409" Received: from black.fi.intel.com ([10.237.72.86]) by fmsmga002.fm.intel.com with ESMTP; 01 Jun 2015 07:48:11 -0700 Received: by black.fi.intel.com (Postfix, from userid 1003) id B3DBC5B1; Mon, 1 Jun 2015 17:48:05 +0300 (EEST) From: Andy Shevchenko To: "Rafael J . Wysocki" , linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, Greg Kroah-Hartman , Vinod Koul , Lee Jones , Andrew Morton , Mika Westerberg , linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, Heikki Krogerus , Jarkko Nikula , "Wysocki, Rafael J" , Mike Turquette Cc: Andy Shevchenko Subject: [PATCH v3 5/8] driver core: implement device_for_each_child_reverse() Date: Mon, 1 Jun 2015 17:47:59 +0300 Message-Id: <1433170082-117462-6-git-send-email-andriy.shevchenko@linux.intel.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1433170082-117462-1-git-send-email-andriy.shevchenko@linux.intel.com> References: <1433170082-117462-1-git-send-email-andriy.shevchenko@linux.intel.com> Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The new function device_for_each_child_reverse() is helpful to traverse the registered devices in a reversed order, e.g. in the case when an operation on each device should be done first on the last added device, then on one before last and so on. Signed-off-by: Andy Shevchenko Acked-by: Greg Kroah-Hartman --- drivers/base/core.c | 43 +++++++++++++++++++++++++++++++++++++++++++ include/linux/device.h | 2 ++ 2 files changed, 45 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index 21d1303..69b2acc 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1252,6 +1252,19 @@ void device_unregister(struct device *dev) } EXPORT_SYMBOL_GPL(device_unregister); +static struct device *prev_device(struct klist_iter *i) +{ + struct klist_node *n = klist_prev(i); + struct device *dev = NULL; + struct device_private *p; + + if (n) { + p = to_device_private_parent(n); + dev = p->device; + } + return dev; +} + static struct device *next_device(struct klist_iter *i) { struct klist_node *n = klist_next(i); @@ -1342,6 +1355,36 @@ int device_for_each_child(struct device *parent, void *data, EXPORT_SYMBOL_GPL(device_for_each_child); /** + * device_for_each_child_reverse - device child iterator in reversed order. + * @parent: parent struct device. + * @fn: function to be called for each device. + * @data: data for the callback. + * + * Iterate over @parent's child devices, and call @fn for each, + * passing it @data. + * + * We check the return of @fn each time. If it returns anything + * other than 0, we break out and return that value. + */ +int device_for_each_child_reverse(struct device *parent, void *data, + int (*fn)(struct device *dev, void *data)) +{ + struct klist_iter i; + struct device *child; + int error = 0; + + if (!parent->p) + return 0; + + klist_iter_init(&parent->p->klist_children, &i); + while ((child = prev_device(&i)) && !error) + error = fn(child, data); + klist_iter_exit(&i); + return error; +} +EXPORT_SYMBOL_GPL(device_for_each_child_reverse); + +/** * device_find_child - device iterator for locating a particular device. * @parent: parent struct device * @match: Callback function to check device diff --git a/include/linux/device.h b/include/linux/device.h index 6558af9..cf404a0 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -928,6 +928,8 @@ extern int __must_check device_add(struct device *dev); extern void device_del(struct device *dev); extern int device_for_each_child(struct device *dev, void *data, int (*fn)(struct device *dev, void *data)); +extern int device_for_each_child_reverse(struct device *dev, void *data, + int (*fn)(struct device *dev, void *data)); extern struct device *device_find_child(struct device *dev, void *data, int (*match)(struct device *dev, void *data)); extern int device_rename(struct device *dev, const char *new_name);