linux-kernel - Re: [PATCH v4 10/10] PM: EM: Use scope-based cleanup helper

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Message-ID: <037855bf-c878-4794-b145-266a36302fc3@kernel.org>
Date: Wed, 3 Sep 2025 15:43:18 +0200
From: Krzysztof Kozlowski <krzk@...nel.org>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: Zihuan Zhang <zhangzihuan@...inos.cn>,
 Viresh Kumar <viresh.kumar@...aro.org>,
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>,
 Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
 Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
 Michael Ellerman <mpe@...erman.id.au>, Alim Akhtar
 <alim.akhtar@...sung.com>, Thierry Reding <thierry.reding@...il.com>,
 MyungJoo Ham <myungjoo.ham@...sung.com>,
 Kyungmin Park <kyungmin.park@...sung.com>,
 Chanwoo Choi <cw00.choi@...sung.com>,
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 Prasanna Kumar T S M <ptsm@...ux.microsoft.com>,
 Sudeep Holla <sudeep.holla@....com>, Yicong Yang <yangyicong@...ilicon.com>,
 linux-pm@...r.kernel.org, linux-acpi@...r.kernel.org,
 linuxppc-dev@...ts.ozlabs.org, linux-arm-kernel@...ts.infradead.org,
 intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
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Subject: Re: [PATCH v4 10/10] PM: EM: Use scope-based cleanup helper

On 03/09/2025 15:41, Rafael J. Wysocki wrote:
>>>  em_cpufreq_update_efficiencies(struct device *dev, struct em_perf_state *table)
>>>  {
>>>       struct em_perf_domain *pd = dev->em_pd;
>>> -     struct cpufreq_policy *policy;
>>> +     struct cpufreq_policy *policy __free(put_cpufreq_policy) = NULL;
>>
>> This is not really correct coding style. Please read how to use
>> cleanup.h expressed in that header. You should have here proper
>> constructor or this should be moved. Or this should not be __free()...
> 
> I gather that this is what you mean (quoted verbatim from cleanup.h)
> 
>  * Given that the "__free(...) = NULL" pattern for variables defined at
>  * the top of the function poses this potential interdependency problem
>  * the recommendation is to always define and assign variables in one
>  * statement and not group variable definitions at the top of the
>  * function when __free() is used.
> 
> and thanks for pointing this out!

... and the only exception would be if there is no single constructor,
but multiple (in if() block). That's not the case here, I think.

Best regards,
Krzysztof