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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6DF31C433EF for ; Mon, 13 Jun 2022 11:21:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353063AbiFMLTI (ORCPT ); Mon, 13 Jun 2022 07:19:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352946AbiFMLOs (ORCPT ); Mon, 13 Jun 2022 07:14:48 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2FDE8F0E; Mon, 13 Jun 2022 03:37:22 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EAFB0D6E; Mon, 13 Jun 2022 03:37:21 -0700 (PDT) Received: from [10.57.35.216] (unknown [10.57.35.216]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 67F4A3F73B; Mon, 13 Jun 2022 03:37:20 -0700 (PDT) Message-ID: <5bac6f98-e1ba-3584-6eac-21eeaaa0ed26@arm.com> Date: Mon, 13 Jun 2022 11:37:18 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH 1/3] thermal: cpufreq_cooling: Use a copy of local ops for each cooling device Content-Language: en-US To: Viresh Kumar Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, daniel.lezcano@linaro.org, amitk@kernel.org, rui.zhang@intel.com, rafael@kernel.org, dietmar.eggemann@arm.com References: <20220610100343.32378-1-lukasz.luba@arm.com> <20220613091611.ncd2hziu4nbyip4x@vireshk-i7> From: Lukasz Luba In-Reply-To: <20220613091611.ncd2hziu4nbyip4x@vireshk-i7> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Viresh, Thank you for the ACKs in the other patches and suggestion in this one. On 6/13/22 10:16, Viresh Kumar wrote: > On 10-06-22, 11:03, Lukasz Luba wrote: >> It is very unlikely that one CPU cluster would have the EM and some other >> won't have it (because EM registration failed or DT lacks needed entry). >> Although, we should avoid modifying global variable with callbacks anyway. >> Redesign this and add safety for such situation. >> >> Signed-off-by: Lukasz Luba >> --- >> drivers/thermal/cpufreq_cooling.c | 16 +++++++++++++--- >> 1 file changed, 13 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c >> index b8151d95a806..e33183785fac 100644 >> --- a/drivers/thermal/cpufreq_cooling.c >> +++ b/drivers/thermal/cpufreq_cooling.c >> @@ -554,7 +554,12 @@ __cpufreq_cooling_register(struct device_node *np, >> /* max_level is an index, not a counter */ >> cpufreq_cdev->max_level = i - 1; >> >> - cooling_ops = &cpufreq_cooling_ops; >> + cooling_ops = kmemdup(&cpufreq_cooling_ops, sizeof(*cooling_ops), >> + GFP_KERNEL); > > I don't like the way we are duplicating the ops here. Instead of this it would > be better to add the OPs field in the cooling device structure and fill its > fields from here. The ops structure will be allocated with the cooling device > itself. > I think I know what you mean. Make sense. There are quite a few different cooling types of devices which are using the API thermal_of_cooling_device_register() with the custom 'ops'. We probably don't want to disturb that well working drivers and ecosystem. Here, I've tried to align this code with the devfreq_cooling, but I might actually apply your suggestion into the devfreq cooling (so they will be still aligned). In that case both struct devfreq_cooling_device and struct cpufreq_cooling_device would get a new field: struct thermal_cooling_device_ops cooling_ops; We could then remove the 'global' variables: devfreq_cooling_ops and cpufreq_cooling_ops from where we copy. Then we would do the needed assignment to the priv 'cooling_ops' in the setup code and just use the old API thermal_of_cooling_device_register() to set the needed 'ops' pointer in the struct thermal_cooling_device. Does this sound OK? Regards, Lukasz