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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 4447FC433E0 for ; Tue, 2 Feb 2021 04:35:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0225864E9C for ; Tue, 2 Feb 2021 04:35:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231683AbhBBEfG (ORCPT ); Mon, 1 Feb 2021 23:35:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231624AbhBBEfD (ORCPT ); Mon, 1 Feb 2021 23:35:03 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1F87C061786 for ; Mon, 1 Feb 2021 20:33:51 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id 203so22425350ybz.2 for ; Mon, 01 Feb 2021 20:33:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=fSgRORThi3AA91PkRefUmvo52xoDuhhzbNgdJNcm8BQ=; b=aEX9NXcV8QEW4XVKUuhSyQsSbYFvnqTTdZ4c1y0Z6KG0Q/DdWLudlEjemR9SLkH9u5 svzrnsEZ8EhRuGQHs1/ACl9y1myBW4Jfai/c1TKll6U/3DeKUAhK0W1RG5jApSQB3lNC pPbcTd8NsbxVJc7HKEYPN6OEwbMvrxprnysdFonYJ2/sMMvbXeiPOZY23yxoE7251oGb BbkXB07PmPjGtVHJPGqgNNfoVWlhNdZ2aiPTpaux981o4BGQBvZHJEIYKbGtXRJmxgev kG+MS4KLZ+Iux/96AJzn4AfdcQlQv6rwBWfk8OXt+j/1Qrfhu8r2+DD6VTisC7yKsnqn Ik6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=fSgRORThi3AA91PkRefUmvo52xoDuhhzbNgdJNcm8BQ=; b=mDBLgIb6ievU2sTFlo4UwNhhVBf/5+ubHA21ZLLdrwsBbbC5tiAozZHxK7JwhsOgUs 2LMrXvZjbYyuCNK8DJ9O27Fti9eiBWaI+viFoLJJmt54mQPj9iiR3c3tvMbpvfVnGAz9 yyzNv/Flq2H9myRYuAjd7JZ8QZFIcX1I1bU/8iIB9pdVXB6NQFd8B70mJv6K3SS4jueZ avvLb44KQUKwHvrtCjTbMPWxYaozgaRDCd3fdtPPkY4OOxHSfGFJvh7ZGEe8fmvSPH96 EG9pLW+MLcGATTjIyB/QCvfOec8skuG9cPkMzW6W8oe5tgrrY0n+IsZbdaeQlM5LOrml Ib2g== X-Gm-Message-State: AOAM531ZYB5tsoQBAUK5M8RAFyTKHLOhjC2Z7AjwccaW6XCxOfcfnYW0 PZL+69O7SN9QRrp0d8mtRME/78G+2bhOJ7U= X-Google-Smtp-Source: ABdhPJyFG1Ia3x5SwBMx8tCTSeK0b66Tc8aeFpXD+/Uw4PFngSMbVCtmHjPwj1NFK+UCdFxD43+HG3zfrQ/+Yuw= Sender: "saravanak via sendgmr" X-Received: from saravanak.san.corp.google.com ([2620:15c:2d:3:7220:84ff:fe09:fedc]) (user=saravanak job=sendgmr) by 2002:a25:ce4c:: with SMTP id x73mr24260093ybe.301.1612240430988; Mon, 01 Feb 2021 20:33:50 -0800 (PST) Date: Mon, 1 Feb 2021 20:33:42 -0800 In-Reply-To: <20210202043345.3778765-1-saravanak@google.com> Message-Id: <20210202043345.3778765-2-saravanak@google.com> Mime-Version: 1.0 References: <20210202043345.3778765-1-saravanak@google.com> X-Mailer: git-send-email 2.30.0.365.g02bc693789-goog Subject: [PATCH v2 1/3] driver core: fw_devlink: Detect supplier devices that will never be added From: Saravana Kannan To: Greg Kroah-Hartman , "Rafael J. Wysocki" , Marek Szyprowski , Geert Uytterhoeven , Marc Zyngier , Tudor Ambarus , Linus Walleij , Bartosz Golaszewski , Martin Kaiser , Rob Herring , Frank Rowand , Len Brown , Saravana Kannan Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-acpi@vger.kernel.org, kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org During the initial parsing of firmware by fw_devlink, fw_devlink might infer that some supplier firmware nodes would get populated as devices. But the inference is not always correct. This patch tries to logically detect and fix such mistakes as boot progresses or more devices probe. fw_devlink makes a fundamental assumption that once a device binds to a driver, it will populate (i.e: add as struct devices) all the child firmware nodes that could be populated as devices (if they aren't populated already). So, whenever a device probes, we check all its child firmware nodes. If a child firmware node has a corresponding device populated, we don't modify the child node or its descendants. However, if a child firmware node has not been populated as a device, we delete all the fwnode links where the child node or its descendants are suppliers. This ensures that no other device is blocked on a firmware node that will never be populated as a device. We also mark such fwnodes as NOT_DEVICE, so that no new fwnode links are created with these nodes as suppliers. Fixes: e590474768f1 ("driver core: Set fw_devlink=on by default") Signed-off-by: Saravana Kannan --- drivers/base/core.c | 31 ++++++++++++++++++++++++++++--- include/linux/fwnode.h | 2 ++ 2 files changed, 30 insertions(+), 3 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 484a942884ba..c95b1daabac7 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -148,6 +148,21 @@ void fwnode_links_purge(struct fwnode_handle *fwnode) fwnode_links_purge_consumers(fwnode); } +static void fw_devlink_purge_absent_suppliers(struct fwnode_handle *fwnode) +{ + struct fwnode_handle *child; + + /* Don't purge consumer links of an added child */ + if (fwnode->dev) + return; + + fwnode->flags |= FWNODE_FLAG_NOT_DEVICE; + fwnode_links_purge_consumers(fwnode); + + fwnode_for_each_available_child_node(fwnode, child) + fw_devlink_purge_absent_suppliers(child); +} + #ifdef CONFIG_SRCU static DEFINE_MUTEX(device_links_lock); DEFINE_STATIC_SRCU(device_links_srcu); @@ -1154,12 +1169,22 @@ void device_links_driver_bound(struct device *dev) LIST_HEAD(sync_list); /* - * If a device probes successfully, it's expected to have created all + * If a device binds successfully, it's expected to have created all * the device links it needs to or make new device links as it needs - * them. So, it no longer needs to wait on any suppliers. + * them. So, fw_devlink no longer needs to create device links to any + * of the device's suppliers. + * + * Also, if a child firmware node of this bound device is not added as + * a device by now, assume it is never going to be added and make sure + * other devices don't defer probe indefinitely by waiting for such a + * child device. */ - if (dev->fwnode && dev->fwnode->dev == dev) + if (dev->fwnode && dev->fwnode->dev == dev) { + struct fwnode_handle *child; fwnode_links_purge_suppliers(dev->fwnode); + fwnode_for_each_available_child_node(dev->fwnode, child) + fw_devlink_purge_absent_suppliers(child); + } device_remove_file(dev, &dev_attr_waiting_for_supplier); device_links_write_lock(); diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h index fde4ad97564c..21082f11473f 100644 --- a/include/linux/fwnode.h +++ b/include/linux/fwnode.h @@ -19,8 +19,10 @@ struct device; * fwnode link flags * * LINKS_ADDED: The fwnode has already be parsed to add fwnode links. + * NOT_DEVICE: The fwnode will never be populated as a struct device. */ #define FWNODE_FLAG_LINKS_ADDED BIT(0) +#define FWNODE_FLAG_NOT_DEVICE BIT(1) struct fwnode_handle { struct fwnode_handle *secondary; -- 2.30.0.365.g02bc693789-goog