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=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 8CDAEC4332B for ; Sat, 6 Feb 2021 02:33:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7326564F70 for ; Sat, 6 Feb 2021 02:33:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230229AbhBFCdB (ORCPT ); Fri, 5 Feb 2021 21:33:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37426 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230058AbhBFCcO (ORCPT ); Fri, 5 Feb 2021 21:32:14 -0500 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2D996C0698DE for ; Fri, 5 Feb 2021 14:26:52 -0800 (PST) Received: by mail-yb1-xb4a.google.com with SMTP id s7so8772266ybj.0 for ; Fri, 05 Feb 2021 14:26:52 -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=223PDDzeAXN7fiB0Z3sv31/CUo0CMPx1p1AufcopYWI=; b=SFHQmMRc/ic1nmrT5IMiYstkL++tDL7Z3c9ojJSjDDxJdd2i0nznkXSFR68OUU+aVL 37l+IB6klV569hlqPafHkvF6+7WsET3whuds9yrB7AV+RdCxsQ77OXj4J7Tcyq8/Ykby AlApFXR5yrG/7Vz11J14XoDvvGtfu1xCPL8V4LNO83ZHxI6bzavvye1rrEa6QHHFK9ZC VbK5aLF05CCF+bWVcucqMPqSUnnHjKES2+MRdskFBHbYTLhsN1Fzt8tWmeiWWfnkvi6G ubCkpqgDZw/sb8byBLZrzDfglYOud2eHQ2Bdkq3sgX+3NHRqCEOzx+TOG8IfoQk25pne myDA== 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=223PDDzeAXN7fiB0Z3sv31/CUo0CMPx1p1AufcopYWI=; b=df6ocP011f/l4my46+EfMmRwwYibRTwOIYsxvnZh8XcAlVWFz+UgWel/fgl9XvcTdh z3vMW92OqutP9mWm7jsPEX7Z12Drf0A5hXGdIDdsD/q4qd7YjQ0zAQdgOCXAZyJgc/cH JlLDNbD9Oo/SVoNTXzG4Bjz2ght8hTbkjpqUQpTwummYRMy44jdL+DJwdHCPA7ksmpZf kEUffWdSeSFx+DY51javTUP0AUCz7jwVUv28dKqKdtWEKcC1OBgziagiWVMjkQlgqdte ghEIQg47ieQ0+Pe35dB1QgLgqRXSPz88W6eR6/C9+H34FqZ6IIRKw2Ty3uetVUfpY+o0 x+nA== X-Gm-Message-State: AOAM530NSVV5msLu+wIDjIXgBQ/pATvZ3fA364QS5X2zShrgUdzQXeo+ 8gzTMnxPDV6ulKvjwbFSzSNuYKyY5YTT1Ag= X-Google-Smtp-Source: ABdhPJxrL9cH3mLaTtg3wJ/fW0QIFeUS4+4EDQLIPatw4HQvuGDNDATg7OIEzUZWu1cx19SOt5U8lpPfcWDatIE= Sender: "saravanak via sendgmr" X-Received: from saravanak.san.corp.google.com ([2620:15c:2d:3:6d36:b798:55d7:f5c5]) (user=saravanak job=sendgmr) by 2002:a25:2693:: with SMTP id m141mr9430134ybm.104.1612564011451; Fri, 05 Feb 2021 14:26:51 -0800 (PST) Date: Fri, 5 Feb 2021 14:26:37 -0800 In-Reply-To: <20210205222644.2357303-1-saravanak@google.com> Message-Id: <20210205222644.2357303-2-saravanak@google.com> Mime-Version: 1.0 References: <20210205222644.2357303-1-saravanak@google.com> X-Mailer: git-send-email 2.30.0.478.g8a0d178c01-goog Subject: [PATCH v4 1/8] driver core: fw_devlink: Detect supplier devices that will never be added From: Saravana Kannan To: Jonathan Corbet , Greg Kroah-Hartman , "Rafael J. Wysocki" , Kevin Hilman , Ulf Hansson , Len Brown , Len Brown , Pavel Machek , Michael Turquette , Stephen Boyd , Rob Herring , Frank Rowand , Marc Zyngier , Thomas Gleixner , Saravana Kannan Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-clk@vger.kernel.org, devicetree@vger.kernel.org, linux-acpi@vger.kernel.org, Marek Szyprowski , Geert Uytterhoeven , kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-acpi@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 Acked-by: Rafael J. Wysocki --- 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; -- 2.30.0.478.g8a0d178c01-goog