From patchwork Fri Jan 5 01:18:42 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 10145911 X-Patchwork-Delegate: rjw@sisk.pl Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 349EE60244 for ; Fri, 5 Jan 2018 01:20:28 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 771CD2859F for ; Fri, 5 Jan 2018 01:20:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 75069288FA; Fri, 5 Jan 2018 01:20:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EDE3F2859F for ; Fri, 5 Jan 2018 01:20:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751166AbeAEBTu (ORCPT ); Thu, 4 Jan 2018 20:19:50 -0500 Received: from cloudserver094114.home.pl ([79.96.170.134]:48335 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751100AbeAEBTt (ORCPT ); Thu, 4 Jan 2018 20:19:49 -0500 Received: from 79.184.254.214.ipv4.supernova.orange.pl (79.184.254.214) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.82) id ef11a1fc1f2ce71c; Fri, 5 Jan 2018 02:19:48 +0100 From: "Rafael J. Wysocki" To: Linux PM Cc: Linux PCI , Tony Lindgren , "Rafael J. Wysocki" , JeffyChen , Linux Kernel Mailing List , Bjorn Helgaas , Shawn Lin , Brian Norris , Doug Anderson , Rob Herring , Frank Rowand Subject: [PATCH v2] PM / wakeup: Do not fail dev_pm_attach_wake_irq() unnecessarily Date: Fri, 05 Jan 2018 02:18:42 +0100 Message-ID: <3262092.gurR7s35C6@aspire.rjw.lan> In-Reply-To: <1542734.kK7NjWylRh@aspire.rjw.lan> References: <20171225114742.18920-1-jeffy.chen@rock-chips.com> <6120485.xubBpvge6h@aspire.rjw.lan> <1542734.kK7NjWylRh@aspire.rjw.lan> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rafael J. Wysocki Returning an error code from dev_pm_attach_wake_irq() if device_wakeup_attach_irq() called by it returns an error is pointless, because the wakeup source used by it may be deleted by user space via sysfs at any time and in particular right after dev_pm_attach_wake_irq() has returned. Moreover, it requires the callers of dev_pm_attach_wake_irq() to create that wakeup source via device_wakeup_enable() upfront, but that obviously is racy with respect to the sysfs-based manipulations of it. To avoid the race, modify device_wakeup_attach_irq() to check that the wakeup source it is going to use is there (and return early otherwise), make it void (as it cannot fail after that change) and make dev_pm_attach_wake_irq() to simply call it for the device unconditionally. Tested-by: Tony Lindgren Signed-off-by: Rafael J. Wysocki --- The previous version didn't compile with CONFIG_PM_SLEEP unset. The changes from it to v2 are not essential for the code flow, so I have retained the Tested-by: tag from Tony. Thanks, Rafael --- drivers/base/power/power.h | 11 +++-------- drivers/base/power/wakeirq.c | 8 +++----- drivers/base/power/wakeup.c | 11 ++++------- 3 files changed, 10 insertions(+), 20 deletions(-) Index: linux-pm/drivers/base/power/wakeirq.c =================================================================== --- linux-pm.orig/drivers/base/power/wakeirq.c +++ linux-pm/drivers/base/power/wakeirq.c @@ -33,7 +33,6 @@ static int dev_pm_attach_wake_irq(struct struct wake_irq *wirq) { unsigned long flags; - int err; if (!dev || !wirq) return -EINVAL; @@ -45,12 +44,11 @@ static int dev_pm_attach_wake_irq(struct return -EEXIST; } - err = device_wakeup_attach_irq(dev, wirq); - if (!err) - dev->power.wakeirq = wirq; + dev->power.wakeirq = wirq; + device_wakeup_attach_irq(dev, wirq); spin_unlock_irqrestore(&dev->power.lock, flags); - return err; + return 0; } /** Index: linux-pm/drivers/base/power/wakeup.c =================================================================== --- linux-pm.orig/drivers/base/power/wakeup.c +++ linux-pm/drivers/base/power/wakeup.c @@ -291,22 +291,19 @@ EXPORT_SYMBOL_GPL(device_wakeup_enable); * * Call under the device's power.lock lock. */ -int device_wakeup_attach_irq(struct device *dev, +void device_wakeup_attach_irq(struct device *dev, struct wake_irq *wakeirq) { struct wakeup_source *ws; ws = dev->power.wakeup; - if (!ws) { - dev_err(dev, "forgot to call device_init_wakeup?\n"); - return -EINVAL; - } + if (!ws) + return; if (ws->wakeirq) - return -EEXIST; + dev_err(dev, "Leftover wakeup IRQ found, overriding\n"); ws->wakeirq = wakeirq; - return 0; } /** Index: linux-pm/drivers/base/power/power.h =================================================================== --- linux-pm.orig/drivers/base/power/power.h +++ linux-pm/drivers/base/power/power.h @@ -41,20 +41,15 @@ extern void dev_pm_disable_wake_irq_chec #ifdef CONFIG_PM_SLEEP -extern int device_wakeup_attach_irq(struct device *dev, - struct wake_irq *wakeirq); +extern void device_wakeup_attach_irq(struct device *dev, struct wake_irq *wakeirq); extern void device_wakeup_detach_irq(struct device *dev); extern void device_wakeup_arm_wake_irqs(void); extern void device_wakeup_disarm_wake_irqs(void); #else -static inline int -device_wakeup_attach_irq(struct device *dev, - struct wake_irq *wakeirq) -{ - return 0; -} +static inline void device_wakeup_attach_irq(struct device *dev, + struct wake_irq *wakeirq) {} static inline void device_wakeup_detach_irq(struct device *dev) {