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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 A1601C48BD3 for ; Wed, 26 Jun 2019 12:52:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6B55320665 for ; Wed, 26 Jun 2019 12:52:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="xL6clskg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727139AbfFZMwR (ORCPT ); Wed, 26 Jun 2019 08:52:17 -0400 Received: from mail-wm1-f65.google.com ([209.85.128.65]:55471 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726948AbfFZMwQ (ORCPT ); Wed, 26 Jun 2019 08:52:16 -0400 Received: by mail-wm1-f65.google.com with SMTP id a15so1980964wmj.5 for ; Wed, 26 Jun 2019 05:52:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=subject:to:cc:references:from:openpgp:autocrypt:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=97XC3JrNltERoKp78ltTZCo7yY8E04N6diR+9e3qm5w=; b=xL6clskgL+7wAvMzUxDLYqjsznkQlKFP8SlacSEkPcwJ1oJoX9L2uQtZGV4gSMIATH hc2GZbHrY4r2IJRwhuQT3WMoMxg/UHTzm8JU3X+MHdtk94wBWcw10D00hpdFsLNfKgiq 4Qne6l9Zkqu3/RqUjyn71NnG8LKfFf8/jMIf+FKQjD17sFkU/JbxVelKZCIBewNxej3J Hp55AQeIhZtFb5rWLca5HAYTaPUZ+OiDk6MMvbaDHf1W81qjuNQXThgymcdQL7ISrJTZ VfmAXuNbCiLWnR06FZAC7UMFT2tmak1AvxJ8hLgltyOsvy+tZY6/164MX0kTFco+/AgP 2pww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:openpgp:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=97XC3JrNltERoKp78ltTZCo7yY8E04N6diR+9e3qm5w=; b=ImzAVYd3d5+MSwUhpsDPC6VvTccowcQSSUmnLirl1GMya1LWBMjf+giaqaOj7HkEZv bEI0h1hIEZj6zdOES7lrtzFhYW48U/WR2AETF7GREPN82BwGwlecpyOn0iTGf/f1xGli 6Qr4rlcElsc0t12wRFXc9f5/ikM7QhO0LjY13+HVI7dK/lovsCh2YzhN2RJM3pcEjE6e yiIlYoWLpZrIuEL0GsH5wODCk28RqWD4lEGjxBqLpYlOcXeYQ5zNHeAN+A3iqocn8Nyg 1pj1I4Z6tZShziw06FoymjPyEUzcG+9HORwwKfnfrM72Qgw7SyjNoUjLue8Pnnh3nRfb bd+A== X-Gm-Message-State: APjAAAXNCDx3m+2R4T8FdSvbLdeEvPQCoOvR27pvs/4CxWrMXp8CAFUu G/6jWa5UQZ6pY6m4N4Rc4/8dDw== X-Google-Smtp-Source: APXvYqzvFQa7PDBk+gmeInRwTGUKFvktKTGYr3JUdfnyUpcb0PEKwQjYF0CfhE3ozU7I4EFDxXp0xw== X-Received: by 2002:a7b:cc86:: with SMTP id p6mr2466384wma.123.1561553533241; Wed, 26 Jun 2019 05:52:13 -0700 (PDT) Received: from [192.168.0.41] (26.92.130.77.rev.sfr.net. [77.130.92.26]) by smtp.googlemail.com with ESMTPSA id x17sm16401528wrq.64.2019.06.26.05.52.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Jun 2019 05:52:12 -0700 (PDT) Subject: Re: [PATCH V3 2/3] thermal/drivers/cpu_cooling: Unregister with the policy To: "Rafael J. Wysocki" Cc: Viresh Kumar , "Rafael J. Wysocki" , Eduardo Valentin , Linux Kernel Mailing List , Sudeep Holla , Amit Daniel Kachhap , Javi Merino , Zhang Rui , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Keerthy , "open list:CPU FREQUENCY DRIVERS - ARM BIG LITTLE" , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , "open list:TI BANDGAP AND THERMAL DRIVER" References: <20190625113244.18146-1-daniel.lezcano@linaro.org> <20190625113244.18146-2-daniel.lezcano@linaro.org> <20190626025831.jmyzyypxr6ezpbtu@vireshk-i7> <20190626063716.cechnzsb75q5lclr@vireshk-i7> <8a9b7bd0-9b21-1ce1-6176-cffff4b8d739@linaro.org> From: Daniel Lezcano Openpgp: preference=signencrypt Autocrypt: addr=daniel.lezcano@linaro.org; prefer-encrypt=mutual; keydata= mQINBFv/yykBEADDdW8RZu7iZILSf3zxq5y8YdaeyZjI/MaqgnvG/c3WjFaunoTMspeusiFE sXvtg3ehTOoyD0oFjKkHaia1Zpa1m/gnNdT/WvTveLfGA1gH+yGes2Sr53Ht8hWYZFYMZc8V 2pbSKh8wepq4g8r5YI1XUy9YbcTdj5mVrTklyGWA49NOeJz2QbfytMT3DJmk40LqwK6CCSU0 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iqWjuat8/HWc01yEd8rtkGuUcMqbCi1XhcAmkaOnX8FYscMRoyyMrWClRZEQRokqZIj79+PR adkDXtr4MeL8BaB7Ij2oyRVjXUwhFQNKi5Z5Rve0a3zvGkkqw8Mz20BOksjSWjAF6g9byukl CUVjC03PdMSufNLK06x5hPc/c4tFR4J9cLrV+XxdCX7r0zGos9SzTPGNuIk1LK++S3EJhLFj 4eoWtNhMWc1uiTf9ENza0ntqH9XBWEQ6IA1gubCniGG+Xg== Message-ID: <81eed47f-9439-abd3-8b73-56ccf5137be3@linaro.org> Date: Wed, 26 Jun 2019 14:52:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On 26/06/2019 13:28, Rafael J. Wysocki wrote: > On Wed, Jun 26, 2019 at 12:19 PM Daniel Lezcano > wrote: >> >> On 26/06/2019 11:06, Rafael J. Wysocki wrote: >>> On Wed, Jun 26, 2019 at 8:37 AM Viresh Kumar wrote: >>>> >>>> On 26-06-19, 08:02, Daniel Lezcano wrote: >>>>> On 26/06/2019 04:58, Viresh Kumar wrote: >>>>>> On 25-06-19, 13:32, Daniel Lezcano wrote: >>>>>>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c >>>>>>> index aee024e42618..f07454249fbc 100644 >>>>>>> --- a/drivers/cpufreq/cpufreq.c >>>>>>> +++ b/drivers/cpufreq/cpufreq.c >>>>>>> @@ -1379,8 +1379,8 @@ static int cpufreq_online(unsigned int cpu) >>>>>>> cpufreq_driver->ready(policy); >>>>>>> >>>>>>> if (cpufreq_thermal_control_enabled(cpufreq_driver)) >>>>>>> - policy->cdev = of_cpufreq_cooling_register(policy); >>>>>>> - >>>>>>> + of_cpufreq_cooling_register(policy); >>>>>>> + >>>>>> >>>>>> We don't need any error checking here anymore ? >>>>> >>>>> There was no error checking initially. This comment and the others below >>>>> are for an additional patch IMO, not a change in this one. >>>> >>>> right, but ... >>>> >>>>>>> -void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev) >>>>>>> +void cpufreq_cooling_unregister(struct cpufreq_policy *policy) >>>>>>> { >>>>>>> struct cpufreq_cooling_device *cpufreq_cdev; >>>>>>> bool last; >>>>>>> >>>>>>> - if (!cdev) >>>>>>> - return; >>>> >>>> we used to return without any errors from here. Now we will have >>>> problems if regsitering fails for some reason. >>> >>> Specifically, the last cpufreq_cdev in the list will be unregistered >>> AFAICS, and without removing it from the list for that matter, which >>> isn't what the caller wants. >> >> Indeed, >> >> What about the resulting code above: >> >> void __cpufreq_cooling_unregister(struct cpufreq_cooling_device >> *cpufreq_cdev, int last) >> { >> /* Unregister the notifier for the last cpufreq cooling device */ >> if (last) >> cpufreq_unregister_notifier(&thermal_cpufreq_notifier_block, >> CPUFREQ_POLICY_NOTIFIER); >> > > Doesn't the notifier need to be unregistered under cooling_list_lock ? I don't think so because the element is no longer in the list and we don't touch the list anymore. Do you see another possible race? >> thermal_cooling_device_unregister(cpufreq_cdev->cdev); >> ida_simple_remove(&cpufreq_ida, cpufreq_cdev->id); >> kfree(cpufreq_cdev->idle_time); >> kfree(cpufreq_cdev); >> } >> >> /** >> >> * cpufreq_cooling_unregister - function to remove cpufreq cooling >> device. >> * @cdev: thermal cooling device pointer. >> >> * >> >> * This interface function unregisters the "thermal-cpufreq-%x" cooling >> device. >> */ >> void cpufreq_cooling_unregister(struct cpufreq_policy *policy) >> { >> struct cpufreq_cooling_device *cpufreq_cdev; >> bool last; >> >> mutex_lock(&cooling_list_lock); >> list_for_each_entry(cpufreq_cdev, &cpufreq_cdev_list, node) { >> if (cpufreq_cdev->policy == policy) { >> list_del(&cpufreq_cdev->node); >> last = list_empty(&cpufreq_cdev_list); >> break; >> } >> } >> mutex_unlock(&cooling_list_lock); >> >> if (cpufreq_cdev->policy == policy) >> __cpufreq_cooling_unregister(cpufreq_cdev, last); >> } >> EXPORT_SYMBOL_GPL(cpufreq_cooling_unregister); >> >> >> >> >> -- >> Linaro.org │ Open source software for ARM SoCs >> >> Follow Linaro: Facebook | >> Twitter | >> Blog >> -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog