From patchwork Thu Dec 17 23:43:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Scally X-Patchwork-Id: 11980987 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 475FEC2BBD4 for ; Thu, 17 Dec 2020 23:44:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 219BC22511 for ; Thu, 17 Dec 2020 23:44:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732351AbgLQXoj (ORCPT ); Thu, 17 Dec 2020 18:44:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37332 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732337AbgLQXoj (ORCPT ); Thu, 17 Dec 2020 18:44:39 -0500 Received: from mail-wr1-x42a.google.com (mail-wr1-x42a.google.com [IPv6:2a00:1450:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B17B1C061282; Thu, 17 Dec 2020 15:43:58 -0800 (PST) Received: by mail-wr1-x42a.google.com with SMTP id w5so210717wrm.11; Thu, 17 Dec 2020 15:43:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ZRG6Du2Q5gaJecr0crPPKYS4mZ7zwOVeReLwF06dy8c=; b=R+U8hHBVOD1dvXrSoEvLCKxYu3++5n4YZ2k3P4lwKlX4SZ7F46ClpBb9F/YER/1WwL 4oRx7vRZYnNXfQMX17iB9DpJHjMKRI2rODDS5quQ/+umxqg69V5hJSQcCwpzCCzLwMhr dx2UIHoiI2lNRhpsstpR0reE1k8dn3KFvj835qp+C8kJe2G72jcom+f/QIkpXdaBrUrp DC94LUztpChvH/lDnHz6CgvK11muVctOTSin4ClAkp4H+YgyaK5Z20iD053EOC9Vdjt7 KQJUSmbRd7f7AYpNj9M1SjxndEbsp4ZKDHu2nM3ZEDZE+97/TARte/nS1oQy4FiQ5U9i psdA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ZRG6Du2Q5gaJecr0crPPKYS4mZ7zwOVeReLwF06dy8c=; b=nC1nwKKARnX6tHJlkCE1MAgDJGYoHxFq4NY8GvW+A9RP4LNZYkYG7rFgseCMDlBygu e8Xz3ctIOlPgfdNLsNJzZiu4yIGDKkRAqoqWWXCqiiuzooTQIJKRIqzaMFnlCK5x1Hsk lHyXwas7iUwt3cVMWOuNVGFjX2uQQTEuwbMMGvLPHULi3pWFd0mJW1L4U7zM6+RXHWUV StKbyJD6AQKFbQxHt82bpg68j+nzYXjIr1uZVQVaxXrbptUm0N83iQM9UlHw+Yv1Jg0G RSUrlsM1CyktOukPoyfq7SO+4GjE0s7Wa4KPxc8h8lQzv6YRxULwh6CcqiDcPT/oX0QW iyeA== X-Gm-Message-State: AOAM531Pg58q2AwXcYtYw8lM/5GJ1ADajHtL2piYtScggHzhvPTKRrql eKLkXf0SEXl6blB6GKAGHKN4kVMH7ZKSI4XI X-Google-Smtp-Source: ABdhPJw7/NIJWKtof/Iqcc4Lel2jeNJDl8wRWMDmfXSr1kBk/rln+Zxy4omURinH+gaxl7UvniPhKw== X-Received: by 2002:a5d:42d0:: with SMTP id t16mr1255839wrr.230.1608248637431; Thu, 17 Dec 2020 15:43:57 -0800 (PST) Received: from valhalla.home ([2.29.208.56]) by smtp.gmail.com with ESMTPSA id o3sm1873575wrc.93.2020.12.17.15.43.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Dec 2020 15:43:56 -0800 (PST) From: Daniel Scally To: linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-media@vger.kernel.org, devel@acpica.org Cc: rjw@rjwysocki.net, lenb@kernel.org, gregkh@linuxfoundation.org, yong.zhi@intel.com, sakari.ailus@linux.intel.com, bingbu.cao@intel.com, tian.shu.qiu@intel.com, mchehab@kernel.org, robert.moore@intel.com, erik.kaneda@intel.com, pmladek@suse.com, rostedt@goodmis.org, sergey.senozhatsky@gmail.com, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, laurent.pinchart+renesas@ideasonboard.com, jacopo+renesas@jmondi.org, kieran.bingham+renesas@ideasonboard.com, linus.walleij@linaro.org, heikki.krogerus@linux.intel.com, kitakar@gmail.com, jorhand@linux.microsoft.com Subject: [PATCH v2 04/12] software_node: Enforce parent before child ordering of nodes arrays Date: Thu, 17 Dec 2020 23:43:29 +0000 Message-Id: <20201217234337.1983732-5-djrscally@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201217234337.1983732-1-djrscally@gmail.com> References: <20201217234337.1983732-1-djrscally@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org 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 Signed-off-by: Daniel Scally Reviewed-by: Laurent Pinchart --- Changes in v2: - Squashed the patches that originally touched these separately - Updated documentation drivers/base/swnode.c | 43 ++++++++++++++++++++++++++++++------------- 1 file changed, 30 insertions(+), 13 deletions(-) diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c index 615a0c93e116..cfd1faea48a7 100644 --- a/drivers/base/swnode.c +++ b/drivers/base/swnode.c @@ -692,7 +692,10 @@ 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 it's .parent pointer set, then it's 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) { @@ -700,33 +703,47 @@ 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); /** * software_node_unregister_nodes - Unregister an array of software nodes - * @nodes: Zero terminated array of software nodes to be unregistered + * @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);