linux-kernel - Re: [PATCH v4 18/21] thermal/drivers/qcom/tsens-v0_1: convert to use devm_request*_irq

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Message-ID: <7b14955f-be89-b04a-a0d1-0988a0c77501@linaro.org>
Date:   Mon, 10 Jul 2023 14:26:59 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Yangtao Li <frank.li@...o.com>, Amit Kucheria <amitk@...nel.org>,
        Thara Gopinath <thara.gopinath@...il.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Zhang Rui <rui.zhang@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        linux-pm@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 18/21] thermal/drivers/qcom/tsens-v0_1: convert to use
 devm_request*_irq_probe()

On 10/07/2023 12:59, Yangtao Li wrote:
> There are more than 700 calls to devm_request_threaded_irq method and
> more than 1000 calls to devm_request_irq method. Most drivers only
> request one interrupt resource, and these error messages are basically
> the same. If error messages are printed everywhere, more than 2000 lines
> of code can be saved by removing the msg in the driver.
> 
> And tglx point out that:
> 
>    If we actually look at the call sites of
>    devm_request_threaded_irq() then the vast majority of them print more or
>    less lousy error messages. A quick grep/sed/awk/sort/uniq revealed
> 
>       519 messages total (there are probably more)
> 
>       352 unique messages
> 
>       323 unique messages after lower casing
> 
>           Those 323 are mostly just variants of the same patterns with
>           slight modifications in formatting and information provided.
> 
>       186 of these messages do not deliver any useful information,
>           e.g. "no irq", "
> 
>       The most useful one of all is: "could request wakeup irq: %d"
> 
>    So there is certainly an argument to be made that this particular
>    function should print a well formatted and informative error message.
> 
>    It's not a general allocator like kmalloc(). It's specialized and in the
>    vast majority of cases failing to request the interrupt causes the
>    device probe to fail. So having proper and consistent information why
>    the device cannot be used _is_ useful.
> 
> So convert to use devm_request*_irq_probe() API, which ensure that all
> error handling branches print error information.
> 
> In this way, when this function fails, the upper-layer functions can
> directly return an error code without missing debugging information.
> Otherwise, the error message will be printed redundantly or missing.
> 
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Krzysztof Kozlowski <krzk@...nel.org>
> Cc: "Uwe Kleine-König" <u.kleine-koenig@...gutronix.de>
> Cc: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> Cc: AngeloGioacchino Del Regno  <angelogioacchino.delregno@...labora.com>
> Signed-off-by: Yangtao Li <frank.li@...o.com>
> ---
>   drivers/thermal/qcom/tsens.c | 23 ++++++++++-------------
>   1 file changed, 10 insertions(+), 13 deletions(-)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>

-- 
With best wishes
Dmitry