From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 535C9C433E6 for ; Thu, 7 Jan 2021 14:06:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 25ADA22D6F for ; Thu, 7 Jan 2021 14:06:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728572AbhAGOGL (ORCPT ); Thu, 7 Jan 2021 09:06:11 -0500 Received: from mga14.intel.com ([192.55.52.115]:40102 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727590AbhAGOGL (ORCPT ); Thu, 7 Jan 2021 09:06:11 -0500 IronPort-SDR: Wj1MXsF7h0dj3Yvtxdpu0kffpjAuuoLQQ7ruJPfY+DqHFbfa+gtzsEQVoCttlKOY1/XAoG8PmJ j9phpFg8MCgQ== X-IronPort-AV: E=McAfee;i="6000,8403,9856"; a="176648039" X-IronPort-AV: E=Sophos;i="5.79,329,1602572400"; d="scan'208";a="176648039" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jan 2021 06:04:25 -0800 IronPort-SDR: L3gYmoYPMdgGKjUkUBKX/YvWN5SQmqkEwQQ+tIbuQzrr4YbnAiI+VolYkbM+jKqhsyCOINIjCY Uhw/79Go4eJQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.79,329,1602572400"; d="scan'208";a="463044655" Received: from kuha.fi.intel.com ([10.237.72.162]) by fmsmga001.fm.intel.com with SMTP; 07 Jan 2021 06:04:19 -0800 Received: by kuha.fi.intel.com (sSMTP sendmail emulation); Thu, 07 Jan 2021 16:04:18 +0200 Date: Thu, 7 Jan 2021 16:04:18 +0200 From: Heikki Krogerus To: Daniel Scally Cc: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-media@vger.kernel.org, devel@acpica.org, rjw@rjwysocki.net, lenb@kernel.org, gregkh@linuxfoundation.org, mchehab@kernel.org, sergey.senozhatsky@gmail.com, yong.zhi@intel.com, sakari.ailus@linux.intel.com, bingbu.cao@intel.com, tian.shu.qiu@intel.com, robert.moore@intel.com, erik.kaneda@intel.com, pmladek@suse.com, rostedt@goodmis.org, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, laurent.pinchart+renesas@ideasonboard.com, jacopo+renesas@jmondi.org, kieran.bingham+renesas@ideasonboard.com, hverkuil-cisco@xs4all.nl, m.felsch@pengutronix.de, niklas.soderlund+renesas@ragnatech.se, prabhakar.mahadev-lad.rj@bp.renesas.com, slongerbeam@gmail.com, Laurent Pinchart Subject: Re: [PATCH v5 05/15] software_node: Enforce parent before child ordering of nodes arrays Message-ID: <20210107140418.GE940479@kuha.fi.intel.com> References: <20210107132838.396641-1-djrscally@gmail.com> <20210107132838.396641-6-djrscally@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210107132838.396641-6-djrscally@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 07, 2021 at 01:28:28PM +0000, Daniel Scally wrote: > Registering software_nodes with the .parent member set to point to a > currently unregistered software_node has the potential for problems, > so enforce parent -> child ordering in arrays passed in to > software_node_register_nodes(). > > Software nodes that are children of another software node should be > unregistered before their parent. To allow easy unregistering of an array > of software_nodes ordered parent to child, reverse the order in which > software_node_unregister_nodes() unregisters software_nodes. > > Suggested-by: Andy Shevchenko > Reviewed-by: Laurent Pinchart > Signed-off-by: Daniel Scally Reviewed-by: Heikki Krogerus > --- > Changes in v5: > > - None > > drivers/base/swnode.c | 42 ++++++++++++++++++++++++++++++------------ > 1 file changed, 30 insertions(+), 12 deletions(-) > > diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c > index 4fcc1a6fb724..166c5cc73f39 100644 > --- a/drivers/base/swnode.c > +++ b/drivers/base/swnode.c > @@ -692,7 +692,11 @@ swnode_register(const struct software_node *node, struct swnode *parent, > * software_node_register_nodes - Register an array of software nodes > * @nodes: Zero terminated array of software nodes to be registered > * > - * Register multiple software nodes at once. > + * Register multiple software nodes at once. If any node in the array > + * has its .parent pointer set (which can only be to another software_node), > + * then its parent **must** have been registered before it is; either outside > + * of this function or by ordering the array such that parent comes before > + * child. > */ > int software_node_register_nodes(const struct software_node *nodes) > { > @@ -700,14 +704,23 @@ int software_node_register_nodes(const struct software_node *nodes) > int i; > > for (i = 0; nodes[i].name; i++) { > - ret = software_node_register(&nodes[i]); > - if (ret) { > - software_node_unregister_nodes(nodes); > - return ret; > + const struct software_node *parent = nodes[i].parent; > + > + if (parent && !software_node_to_swnode(parent)) { > + ret = -EINVAL; > + goto err_unregister_nodes; > } > + > + ret = software_node_register(&nodes[i]); > + if (ret) > + goto err_unregister_nodes; > } > > return 0; > + > +err_unregister_nodes: > + software_node_unregister_nodes(nodes); > + return ret; > } > EXPORT_SYMBOL_GPL(software_node_register_nodes); > > @@ -715,18 +728,23 @@ EXPORT_SYMBOL_GPL(software_node_register_nodes); > * software_node_unregister_nodes - Unregister an array of software nodes > * @nodes: Zero terminated array of software nodes to be unregistered > * > - * Unregister multiple software nodes at once. > + * Unregister multiple software nodes at once. If parent pointers are set up > + * in any of the software nodes then the array **must** be ordered such that > + * parents come before their children. > * > - * NOTE: Be careful using this call if the nodes had parent pointers set up in > - * them before registering. If so, it is wiser to remove the nodes > - * individually, in the correct order (child before parent) instead of relying > - * on the sequential order of the list of nodes in the array. > + * NOTE: If you are uncertain whether the array is ordered such that > + * parents will be unregistered before their children, it is wiser to > + * remove the nodes individually, in the correct order (child before > + * parent). > */ > void software_node_unregister_nodes(const struct software_node *nodes) > { > - int i; > + unsigned int i = 0; > + > + while (nodes[i].name) > + i++; > > - for (i = 0; nodes[i].name; i++) > + while (i--) > software_node_unregister(&nodes[i]); > } > EXPORT_SYMBOL_GPL(software_node_unregister_nodes); > -- > 2.25.1 -- heikki