From patchwork Thu Mar 18 18:15:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 12148973 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 7CC28C433E6 for ; Thu, 18 Mar 2021 18:16:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3B25064E2E for ; Thu, 18 Mar 2021 18:16:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232387AbhCRSQN (ORCPT ); Thu, 18 Mar 2021 14:16:13 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:56600 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232412AbhCRSPo (ORCPT ); Thu, 18 Mar 2021 14:15:44 -0400 Received: from localhost (127.0.0.1) (HELO v370.home.net.pl) by /usr/run/smtp (/usr/run/postfix/private/idea_relay_lmtp) via UNIX with SMTP (IdeaSmtpServer 2.0.3) id a56c98ea21005667; Thu, 18 Mar 2021 19:15:42 +0100 Received: from kreacher.localnet (89-64-80-250.dynamic.chello.pl [89.64.80.250]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by v370.home.net.pl (Postfix) with ESMTPSA id C39A9668FA9; Thu, 18 Mar 2021 19:15:41 +0100 (CET) From: "Rafael J. Wysocki" To: Linux PM , "elaine.zhang" Cc: LKML , Ulf Hansson Subject: [PATCH v1 2/2] PM: runtime: Defer suspending suppliers Date: Thu, 18 Mar 2021 19:15:13 +0100 Message-ID: <2060154.irdbgypaU6@kreacher> In-Reply-To: <5448054.DvuYhMxLoT@kreacher> References: <5448054.DvuYhMxLoT@kreacher> MIME-Version: 1.0 X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeduledrudefiedguddufecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfjqffogffrnfdpggftiffpkfenuceurghilhhouhhtmecuudehtdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephffvufffkfgjfhgggfgtsehtufertddttddvnecuhfhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqnecuggftrfgrthhtvghrnhepffeuvddutdelgfdvtefgiefftddvfffgjeelvdethfehgfekfeeluedvueevvedunecuffhomhgrihhnpehkvghrnhgvlhdrohhrghenucfkphepkeelrdeigedrkedtrddvhedtnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepkeelrdeigedrkedtrddvhedtpdhhvghlohepkhhrvggrtghhvghrrdhlohgtrghlnhgvthdpmhgrihhlfhhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqpdhrtghpthhtoheplhhinhhugidqphhmsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepiihhrghnghhqihhnghesrhhotghkqdgthhhiphhsrdgtohhmpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtohepuhhlfhdrhhgrnhhsshhonheslhhinhgrrhhordhorhhg X-DCC--Metrics: v370.home.net.pl 1024; Body=4 Fuz1=4 Fuz2=4 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Rafael J. Wysocki Because the PM-runtime status of the device is not updated in __rpm_callback(), attempts to suspend the suppliers of the given device triggered by the rpm_put_suppliers() call in there may fail. To fix this (1) modify __rpm_callback() to avoid attempting to actually suspend the suppliers, but only decrease their PM-runtime usage counters and (2) make rpm_suspend() try to suspend the suppliers after changing the device's PM-runtime status, in analogy with the handling of the device's parent. Link: https://lore.kernel.org/linux-pm/CAPDyKFqm06KDw_p8WXsM4dijDbho4bb6T4k50UqqvR1_COsp8g@mail.gmail.com/ Fixes: 21d5c57b3726 ("PM / runtime: Use device links") Reported-by: elaine.zhang Diagnosed-by: Ulf Hansson Signed-off-by: Rafael J. Wysocki Reviewed-by: Ulf Hansson --- drivers/base/power/runtime.c | 45 +++++++++++++++++++++++++++++++++++++------ 1 file changed, 39 insertions(+), 6 deletions(-) Index: linux-pm/drivers/base/power/runtime.c =================================================================== --- linux-pm.orig/drivers/base/power/runtime.c +++ linux-pm/drivers/base/power/runtime.c @@ -305,7 +305,7 @@ static int rpm_get_suppliers(struct devi return 0; } -static void rpm_put_suppliers(struct device *dev) +static void __rpm_put_suppliers(struct device *dev, bool try_to_suspend) { struct device_link *link; @@ -313,10 +313,30 @@ static void rpm_put_suppliers(struct dev device_links_read_lock_held()) { while (refcount_dec_not_one(&link->rpm_active)) - pm_runtime_put(link->supplier); + pm_runtime_put_noidle(link->supplier); + + if (try_to_suspend) + pm_request_idle(link->supplier); } } +static void rpm_put_suppliers(struct device *dev) +{ + __rpm_put_suppliers(dev, true); +} + +static void rpm_try_to_suspend_suppliers(struct device *dev) +{ + struct device_link *link; + int idx = device_links_read_lock(); + + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node, + device_links_read_lock_held()) + pm_request_idle(link->supplier); + + device_links_read_unlock(idx); +} + /** * __rpm_callback - Run a given runtime PM callback for a given device. * @cb: Runtime PM callback to run. @@ -344,8 +364,10 @@ static int __rpm_callback(int (*cb)(stru idx = device_links_read_lock(); retval = rpm_get_suppliers(dev); - if (retval) + if (retval) { + rpm_put_suppliers(dev); goto fail; + } device_links_read_unlock(idx); } @@ -368,9 +390,9 @@ static int __rpm_callback(int (*cb)(stru || (dev->power.runtime_status == RPM_RESUMING && retval))) { idx = device_links_read_lock(); - fail: - rpm_put_suppliers(dev); + __rpm_put_suppliers(dev, false); +fail: device_links_read_unlock(idx); } @@ -642,8 +664,11 @@ static int rpm_suspend(struct device *de goto out; } + if (dev->power.irq_safe) + goto out; + /* Maybe the parent is now able to suspend. */ - if (parent && !parent->power.ignore_children && !dev->power.irq_safe) { + if (parent && !parent->power.ignore_children) { spin_unlock(&dev->power.lock); spin_lock(&parent->power.lock); @@ -652,6 +677,14 @@ static int rpm_suspend(struct device *de spin_lock(&dev->power.lock); } + /* Maybe the suppliers are now able to suspend. */ + if (dev->power.links_count > 0) { + spin_unlock(&dev->power.lock); + + rpm_try_to_suspend_suppliers(dev); + + spin_lock(&dev->power.lock); + } out: trace_rpm_return_int_rcuidle(dev, _THIS_IP_, retval);