Re: [PATCH 02/10] pmdomain: rockchip: Simplify locking with guard()

From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
To: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
	Heiko Stuebner <heiko@sntech.de>, Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konradybcio@kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	imx@lists.linux.dev, linux-arm-msm@vger.kernel.org,
	linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH 02/10] pmdomain: rockchip: Simplify locking with guard()
Date: Tue, 27 Aug 2024 12:30:22 +0200	[thread overview]
Message-ID: <6f2c976c-2757-43c5-805f-e67724328b65@linaro.org> (raw)
In-Reply-To: <20240827105927.00007ac7@Huawei.com>

On 27/08/2024 11:59, Jonathan Cameron wrote:
> On Fri, 23 Aug 2024 14:51:06 +0200
> Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> wrote:
> 
>> Simplify error handling (smaller error handling) over locks with
>> guard().
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> Musing inline.
> 
> LGTM
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> 
>> ---
>>  drivers/pmdomain/rockchip/pm-domains.c | 5 +----
>>  1 file changed, 1 insertion(+), 4 deletions(-)
>>
>> diff --git a/drivers/pmdomain/rockchip/pm-domains.c b/drivers/pmdomain/rockchip/pm-domains.c
>> index 5679ad336a11..538dde58d924 100644
>> --- a/drivers/pmdomain/rockchip/pm-domains.c
>> +++ b/drivers/pmdomain/rockchip/pm-domains.c
>> @@ -910,7 +910,7 @@ static int rockchip_pm_domain_probe(struct platform_device *pdev)
>>  	 * Prevent any rockchip_pmu_block() from racing with the remainder of
>>  	 * setup (clocks, register initialization).
>>  	 */
>> -	mutex_lock(&dmc_pmu_mutex);
>> +	guard(mutex)(&dmc_pmu_mutex);
>>  
>>  	for_each_available_child_of_node_scoped(np, node) {
>>  		error = rockchip_pm_add_one_domain(pmu, node);
>> @@ -943,13 +943,10 @@ static int rockchip_pm_domain_probe(struct platform_device *pdev)
>>  	if (!WARN_ON_ONCE(dmc_pmu))
>>  		dmc_pmu = pmu;
>>  
>> -	mutex_unlock(&dmc_pmu_mutex);
>> -
>>  	return 0;
>>  
>>  err_out:
>>  	rockchip_pm_domain_cleanup(pmu);
> 
> I wonder.  Could you use a devm_add_action_or_reset for this and allow early
> returns throughout?
> 
> Would need to take the lock again perhaps and I haven't checked if there
> is any issue in dropping and retaking the mutex however.
> The block logic is non obvious so I couldn't quickly figure this out.

I will take a look, but as you already pointed out it is a bit further
from trivial functionally-equivalent cleanup. I might mess with the locks.

Best regards,
Krzysztof

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