linux-kernel - Re: [PATCH v2] hwrng: exynos - Fix runtime PM imbalance on error

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Message-ID: <a8bdb9e0-cbe3-85d5-c9ac-619445471b41@canonical.com>
Date:   Thu, 22 Apr 2021 18:31:21 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
To:     Łukasz Stelmach <l.stelmach@...sung.com>
Cc:     Matt Mackall <mpm@...enic.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        linux-samsung-soc@...r.kernel.org, linux-crypto@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Bartłomiej Żolnierkiewicz 
        <b.zolnierkie@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH v2] hwrng: exynos - Fix runtime PM imbalance on error

On 22/04/2021 13:22, Łukasz Stelmach wrote:
> It was <2021-04-22 czw 12:46>, when Krzysztof Kozlowski wrote:
>> On 22/04/2021 12:41, Łukasz Stelmach wrote:
>>> pm_runtime_get_sync() increments the runtime PM usage counter even
>>> the call returns an error code. Thus a pairing decrement is needed
>>> on the error handling path to keep the counter balanced.
>>
>> It's exactly the same as Dinghao's patch:
>> https://lore.kernel.org/linux-samsung-soc/20200522011659.26727-1-dinghao.liu@zju.edu.cn/
>> which you reviewed. It has even the same commit msg
>> (although it's difficult to be creative here).
>>
>> I think it's better to resend his patch instead.
> 
> It isn't the same because it uses pm_runtime_put_noidle() as discussed
> here[1], applied here[2] and advised here[2]. Dinghao didn't prepare
> v3[4] for exynos.

Thanks, makes sense but then I would prefer Marek's approach of
pm_runtime_resume_and_get().

Best regards,
Krzysztof