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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 88664C3A59D for ; Fri, 16 Aug 2019 21:27:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41441217F4 for ; Fri, 16 Aug 2019 21:27:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=android.com header.i=@android.com header.b="A3J5SEaI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727695AbfHPV1r (ORCPT ); Fri, 16 Aug 2019 17:27:47 -0400 Received: from mail-oi1-f194.google.com ([209.85.167.194]:44839 "EHLO mail-oi1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727649AbfHPV1r (ORCPT ); Fri, 16 Aug 2019 17:27:47 -0400 Received: by mail-oi1-f194.google.com with SMTP id k22so5794320oiw.11 for ; Fri, 16 Aug 2019 14:27:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=android.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=aqmSQA31vLUNhr87Xa+IWQLTTVCCaklCI55tBVwyFNQ=; b=A3J5SEaIUVTi9GzBvEYudEnLY+MD/Tms4QCct9Le1jCJ+1WYIAbD+48NaEyqtvfbRh Qe7pfKphAnMr5eryDM3Opv7Gus2oEdfIptH+ke3T8lWJzlA9JPTYcb3oi++PxTcT1mjd YWUTfqhnD+bZLIBnkc36REFChte0qoz/DfKubxH+EQl2xkoOU1ca6IV1pe0LvGO37LKD uU4V13hlIEa8yUjpa0txpKASYcF78pANyvXfalCfMwwLfVEVbDeiuTEo/sNRZe+Q5ph3 ZvER8Ejg/XEyMNC981lqM9ivVQe6iUZsSvO2p+l3jZnDzYEBGoc+uTWqSHr74axyQHej 8+5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=aqmSQA31vLUNhr87Xa+IWQLTTVCCaklCI55tBVwyFNQ=; b=BE+AOaUc3BBOda0Uu3aj/baS5e+8j0zNAKB13yJQxamCJkvAgNGrhSXj5xCHhA4Ln6 JIQBEauz7V50ZfnqK00XMDxxX/z1dtPmXK8seCOOiBbaCDJ71/ZbUdslfg0fhKCSxW9s xCqyA/+Zamps4s/YR0B/kuwrPvybslG/nQF8eH8f/quhHv/DN7qcIFM3s7KEl9PVfOdb pqIoPfROWP7gMoWfDpfx+c+3tIWQdxPRP1ErWJpC7IVpuNSRHllairoi5WRtEC++nRKL KpuFSguMl1ny6PV30P0x5PMTJMyMwkYrQ1T96vW5ctPpiYJKKCMPJmqqRA4t+vrt/Hia Njqw== X-Gm-Message-State: APjAAAWTRerX/FaJDLVqULacaUkD0I44huJwNoJFESpOvFTMyRcUy15s 7UuT9vU3vHDV+Th8X5umKFBnmrcibfwb/x3W70epAg== X-Google-Smtp-Source: APXvYqyUY2tOiKVAj3q1ha+TiJ4c/MJUuqSosee46aTi/hV6edQ9nSXhS/v5n62lG0AS/lTxt6wg3iJ4TDkL+2lmAuw= X-Received: by 2002:a54:4e95:: with SMTP id c21mr5854082oiy.145.1565990866341; Fri, 16 Aug 2019 14:27:46 -0700 (PDT) MIME-Version: 1.0 References: <20190816145602.231163-1-swboyd@chromium.org> In-Reply-To: <20190816145602.231163-1-swboyd@chromium.org> From: Tri Vo Date: Fri, 16 Aug 2019 14:27:35 -0700 Message-ID: Subject: Re: [PATCH] PM / wakeup: Register wakeup class kobj after device is added To: Stephen Boyd Cc: "Rafael J. Wysocki" , LKML , Linux PM , Qian Cai Content-Type: text/plain; charset="UTF-8" Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Fri, Aug 16, 2019 at 7:56 AM Stephen Boyd wrote: > > The device_set_wakeup_enable() function can be called on a device that > hasn't been registered with device_add() yet. This allows the device to > be in a state where wakeup is enabled for it but the device isn't > published to userspace in sysfs yet. > > After commit 986845e747af ("PM / wakeup: Show wakeup sources stats in > sysfs"), calling device_set_wakeup_enable() will fail for a device that > hasn't been registered with the driver core via device_add(). This is > because we try to create sysfs entries for the device and associate a > wakeup class kobject with it before the device has been registered. > Let's follow a similar approach that device_set_wakeup_capable() takes > here and register the wakeup class either from > device_set_wakeup_enable() when the device is already registered, or > from dpm_sysfs_add() when the device is being registered with the driver > core via device_add(). > > Fixes: 986845e747af ("PM / wakeup: Show wakeup sources stats in sysfs") > Reported-by: Qian Cai > Cc: Qian Cai > Cc: Tri Vo > Signed-off-by: Stephen Boyd > --- > drivers/base/power/sysfs.c | 10 +++++++++- > drivers/base/power/wakeup.c | 10 ++++++---- > 2 files changed, 15 insertions(+), 5 deletions(-) > > diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c > index 1b9c281cbe41..27ee00f50bd7 100644 > --- a/drivers/base/power/sysfs.c > +++ b/drivers/base/power/sysfs.c > @@ -5,6 +5,7 @@ > #include > #include > #include > +#include > #include > #include > #include "power.h" > @@ -661,14 +662,21 @@ int dpm_sysfs_add(struct device *dev) > if (rc) > goto err_runtime; > } > + if (dev->power.wakeup) { This conditional checks for the situation when wakeup source registration have been previously attempted, but failed at wakeup_source_sysfs_add(). My concern is that it's not easy to understand what this check does without knowing exactly what device_wakeup_enable() does to dev->power.wakeup before we reach this point. > + rc = wakeup_source_sysfs_add(dev, dev->power.wakeup); > + if (rc) > + goto err_wakeup; > + } > if (dev->power.set_latency_tolerance) { > rc = sysfs_merge_group(&dev->kobj, > &pm_qos_latency_tolerance_attr_group); > if (rc) > - goto err_wakeup; > + goto err_wakeup_source; > } > return 0; > > + err_wakeup_source: > + wakeup_source_sysfs_remove(dev->power.wakeup); > err_wakeup: > sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group); > err_runtime: > diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c > index f7925820b5ca..5817b51d2b15 100644 > --- a/drivers/base/power/wakeup.c > +++ b/drivers/base/power/wakeup.c > @@ -220,10 +220,12 @@ struct wakeup_source *wakeup_source_register(struct device *dev, > > ws = wakeup_source_create(name); > if (ws) { > - ret = wakeup_source_sysfs_add(dev, ws); > - if (ret) { > - wakeup_source_free(ws); > - return NULL; > + if (!dev || device_is_registered(dev)) { Is there a possible race condition here? If dev->power.wakeup check in dpm_sysfs_add() is done at the same time as device_is_registered(dev) check here, then wakeup_source_sysfs_add() won't ever be called? > + ret = wakeup_source_sysfs_add(dev, ws); > + if (ret) { > + wakeup_source_free(ws); > + return NULL; > + } > } > wakeup_source_add(ws); > } > -- > Sent by a computer through tubes >