Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <85e0a85d-6935-11cc-8396-4c3e425188f2@linaro.org>
Date:   Thu, 19 Jan 2023 13:48:00 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.4.2
Subject: Re: [PATCH 3/5] thermal/core: Remove unneeded mutex_destroy()
Content-Language: en-US
To:     "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     "Zhang, Rui" <rui.zhang@intel.com>,
        "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "amitk@kernel.org" <amitk@kernel.org>
References: <20230118211123.111493-1-daniel.lezcano@linaro.org>
 <20230118211123.111493-3-daniel.lezcano@linaro.org>
 <92a6e8494b92f0bb8cb36c98d2237ee3d347c358.camel@intel.com>
 <db701c97-883e-f231-68fa-c851c6a1a862@linaro.org>
 <CAJZ5v0jFQv09MQw8Z0gn1=Yf3JJD=BWKy3+Xy7RWUy1NXAK7wg@mail.gmail.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
In-Reply-To: <CAJZ5v0jFQv09MQw8Z0gn1=Yf3JJD=BWKy3+Xy7RWUy1NXAK7wg@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 19/01/2023 13:11, Rafael J. Wysocki wrote:
> On Thu, Jan 19, 2023 at 10:30 AM Daniel Lezcano
> <daniel.lezcano@linaro.org> wrote:
>>
>> On 19/01/2023 08:41, Zhang, Rui wrote:
>>> On Wed, 2023-01-18 at 22:11 +0100, Daniel Lezcano wrote:
>>>> If the thermal framework fails to initialize, the mutex can be used
>>>> by
>>>> the different functions registering a thermal zone anyway.
>>>
>>> Hmm, even with no governors and unregistered thermal sysfs class?
>>>
>>> IMO, thermal APIs for registering a thermal_zone/cooling_device should
>>> yield early if thermal_init fails.
>>> For other APIs that relies on a valid
>>> thermal_zone_device/thermal_cooling_device pointer, nothing needs to
>>> be changed.
>>>
>>> what do you think?
>>
>> I think you are right.
>>
>> It would be nice if we can check if the thermal class is registered and
>> bail out if not. But there is no function to check that AFAICS.
>>
>> Alternatively we can convert the thermal class static structure to a
>> pointer and set it to NULL in case of error in thermal_init() ?
> 
> It doesn't matter if this is a NULL pointer or a static object that's
> clearly marked as unused.

Without introducing another global variable, is it possible to know if 
the class is used or not ?

-- 
<http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog