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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 92B12C606D1 for ; Mon, 8 Jul 2019 22:56:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F36521707 for ; Mon, 8 Jul 2019 22:56:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="hervEiYD" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728706AbfGHW4r (ORCPT ); Mon, 8 Jul 2019 18:56:47 -0400 Received: from mail-pf1-f201.google.com ([209.85.210.201]:35548 "EHLO mail-pf1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727469AbfGHW4p (ORCPT ); Mon, 8 Jul 2019 18:56:45 -0400 Received: by mail-pf1-f201.google.com with SMTP id r142so11179159pfc.2 for ; Mon, 08 Jul 2019 15:56:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=mgBpCx6CWfEZqhYDHYS+zPohWIoo7fdF1geROPA0ULA=; b=hervEiYDs7Q2SvRkIEf4brdnTQw7MghOqdn01eWpOIXXBzvIUrL4jTkv4icYVN2koO brxuISIVjc9VvRW4aalVzfm6BQjNdpUKauHIJNNcQBkfpNQi3kjOhi9hsiiP11+8K+8p VoIzjJnjaB99WjFGjehw34T0aQndgbmBFZiPaaxqMdFyeiklH+DviZ2YIoH+CmpggYA9 DPb5pu0zmGBundTxk5VBYS4uY8jWR/vjchjNawojxL4wEthSGO5ihTQVXogbPdenT8Ui eTlmueTUJP8c9+pDz1oBrklJ5JjD5CsqSFQiL7gkd2LTWsa4jTUJMsDPCP8tp77WoPh6 3Nww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=mgBpCx6CWfEZqhYDHYS+zPohWIoo7fdF1geROPA0ULA=; b=fTRoaBw90KKsil6VnPBHCjZKJD0ZGvlesqjCZLdkZH5kVThRdFgcueY8bIn47PI1T3 1165QntM/JNgKWn5MO5xp5BWzTttQh/BFr3L4XwgUsvTWWF/EhX5Gw9gG//yGg4KsfmQ RR/IlMSnRYLYE6RrHHBoIIhXViTjP4Y7xyWR8KOEGz18D/SjOTYFl8uWlNTyKn0e91+6 sjgKJbTQWu7cYguja3rcjDXS4nCegMTdnL5CRRae4qaRmEdebI6AcSxQsNJ8wKc2qbFc +VZgwTSC65gCNtHNgTUH46KkLpsgbtt96mn9LlVGS0/q6EQLPypWnwxQubXVM/zQ/eav KXyg== X-Gm-Message-State: APjAAAUCoOf7FZXB2rGwdu9X/yYN65pez4KMBeRlWn32zHR/B5Sdz3se NK8t2lG2sqJdSWnwJEn2SR/PQ6OllR4vI7I= X-Google-Smtp-Source: APXvYqw+JRwFHBWaLEPLqJFvJKQ+G1E3/hF7EaAb3AIHa4dGZbu0e1sAZPJNBDubpeqbj2mmUlAabS326cgaiIU= X-Received: by 2002:a63:1310:: with SMTP id i16mr26194626pgl.187.1562626604106; Mon, 08 Jul 2019 15:56:44 -0700 (PDT) Date: Mon, 8 Jul 2019 15:56:21 -0700 In-Reply-To: <20190708225624.119973-1-saravanak@google.com> Message-Id: <20190708225624.119973-6-saravanak@google.com> Mime-Version: 1.0 References: <20190708225624.119973-1-saravanak@google.com> X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH v4 5/8] driver core: Add APIs to pause/resume sync state callbacks From: Saravana Kannan To: Rob Herring , Mark Rutland , Greg Kroah-Hartman , "Rafael J. Wysocki" , Frank Rowand Cc: Saravana Kannan , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, David Collins , kernel-team@android.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When multiple devices are added after kernel init, some suppliers could be added before their consumer devices get added. In these instances, the supplier devices could get their sync_state callback called right after they probe because the consumers haven't had a chance to create device links to the suppliers. This change adds APIs to pause/resume sync state callbacks so that when multiple devices are added, their sync_state callback evaluation can be postponed to happen after all of them are added. Signed-off-by: Saravana Kannan --- drivers/base/core.c | 34 +++++++++++++++++++++++++++------- drivers/of/platform.c | 5 ++--- include/linux/device.h | 6 ++++-- 3 files changed, 33 insertions(+), 12 deletions(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index dce97b5f3536..1c08f8614ae1 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -46,7 +46,8 @@ early_param("sysfs.deprecated", sysfs_deprecated_setup); /* Device links support. */ static LIST_HEAD(wait_for_suppliers); static DEFINE_MUTEX(wfs_lock); -static bool supplier_sync_state_enabled; +static LIST_HEAD(deferred_sync); +static unsigned int supplier_sync_state_disabled; #ifdef CONFIG_SRCU static DEFINE_MUTEX(device_links_lock); @@ -657,17 +658,32 @@ static void __device_links_supplier_sync_state(struct device *dev) dev->state_synced = true; } -int device_links_supplier_sync_state(struct device *dev, void *data) +void device_links_supplier_sync_state_pause(void) { device_links_write_lock(); - __device_links_supplier_sync_state(dev); + supplier_sync_state_disabled++; device_links_write_unlock(); - return 0; } -void device_links_supplier_sync_state_enable(void) +void device_links_supplier_sync_state_resume(void) { - supplier_sync_state_enabled = true; + struct device *dev, *tmp; + + device_links_write_lock(); + if (!supplier_sync_state_disabled) { + WARN(true, "Unmatched sync_state pause/resume!"); + goto out; + } + supplier_sync_state_disabled--; + if (supplier_sync_state_disabled) + goto out; + + list_for_each_entry_safe(dev, tmp, &deferred_sync, links.defer_sync) { + __device_links_supplier_sync_state(dev); + list_del_init(&dev->links.defer_sync); + } +out: + device_links_write_unlock(); } /** @@ -715,7 +731,9 @@ void device_links_driver_bound(struct device *dev) WARN_ON(link->status != DL_STATE_CONSUMER_PROBE); WRITE_ONCE(link->status, DL_STATE_ACTIVE); - if (supplier_sync_state_enabled) + if (supplier_sync_state_disabled) + list_add_tail(&dev->links.defer_sync, &deferred_sync); + else __device_links_supplier_sync_state(link->supplier); } @@ -826,6 +844,7 @@ void device_links_driver_cleanup(struct device *dev) WRITE_ONCE(link->status, DL_STATE_DORMANT); } + list_del_init(&dev->links.defer_sync); __device_links_no_driver(dev); device_links_write_unlock(); @@ -1797,6 +1816,7 @@ void device_initialize(struct device *dev) INIT_LIST_HEAD(&dev->links.consumers); INIT_LIST_HEAD(&dev->links.suppliers); INIT_LIST_HEAD(&dev->links.needs_suppliers); + INIT_LIST_HEAD(&dev->links.defer_sync); dev->links.status = DL_DEV_NO_DRIVER; } EXPORT_SYMBOL_GPL(device_initialize); diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 4d12d6658999..56b718f09929 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -581,6 +581,7 @@ static int __init of_platform_default_populate_init(void) return -ENODEV; platform_bus_type.add_links = of_link_to_suppliers; + device_links_supplier_sync_state_pause(); /* * Handle certain compatibles explicitly, since we don't want to create * platform_devices for every node in /reserved-memory with a @@ -604,9 +605,7 @@ arch_initcall_sync(of_platform_default_populate_init); static int __init of_platform_sync_state_init(void) { - device_links_supplier_sync_state_enable(); - bus_for_each_dev(&platform_bus_type, NULL, NULL, - device_links_supplier_sync_state); + device_links_supplier_sync_state_resume(); return 0; } late_initcall_sync(of_platform_sync_state_init); diff --git a/include/linux/device.h b/include/linux/device.h index d3c9e70052d8..0ea28cb8c77e 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -926,12 +926,14 @@ enum dl_dev_state { * @suppliers: List of links to supplier devices. * @consumers: List of links to consumer devices. * @needs_suppliers: Hook to global list of devices waiting for suppliers. + * @defer_sync: Hook to global list of devices that have deferred sync_state. * @status: Driver status information. */ struct dev_links_info { struct list_head suppliers; struct list_head consumers; struct list_head needs_suppliers; + struct list_head defer_sync; enum dl_dev_state status; }; @@ -1438,8 +1440,8 @@ struct device_link *device_link_add(struct device *consumer, struct device *supplier, u32 flags); void device_link_del(struct device_link *link); void device_link_remove(void *consumer, struct device *supplier); -int device_links_supplier_sync_state(struct device *dev, void *data); -void device_links_supplier_sync_state_enable(void); +void device_links_supplier_sync_state_pause(void); +void device_links_supplier_sync_state_resume(void); void device_link_remove_from_wfs(struct device *consumer); #ifndef dev_fmt -- 2.22.0.410.gd8fdbe21b5-goog