linux-kernel - Re: [PATCH v5 02/22] thermal/drivers/sun8i: convert to use devm_request*_irq

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Message-ID: <CAJZ5v0iB5arngPxxduafyZ+hbxqTRLXm_5iwNoEcQcqVyCdCYw@mail.gmail.com>
Date:   Fri, 21 Jul 2023 12:45:11 +0200
From:   "Rafael J. Wysocki" <rafael@...nel.org>
To:     Yangtao Li <frank.li@...o.com>
Cc:     Vasily Khoruzhick <anarsoul@...il.com>,
        Yangtao Li <tiny.windzz@...il.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>, Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Samuel Holland <samuel@...lland.org>,
        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-kernel@...ts.infradead.org,
        linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 02/22] thermal/drivers/sun8i: convert to use devm_request*_irq_probe()

On Fri, Jul 21, 2023 at 11:47 AM Yangtao Li <frank.li@...o.com> 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>
> Acked-by: Jernej Skrabec <jernej.skrabec@...il.com>

It is not clear to me what the purpose of sending these patches is.

Because the devm_request_threaded_irq_probe() definition is not there
in the current -rc kernels AFAICS, it looks like they are sent in
order to collect tags from people.  If so, there should be a cover
letter making that clear.

As it stands, it is also unclear how you want them to be merged.

Moreover, sending the series without patch [01/22] to linux-pm has not
been helpful.

Thanks!

> ---
>  drivers/thermal/sun8i_thermal.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/thermal/sun8i_thermal.c b/drivers/thermal/sun8i_thermal.c
> index 195f3c5d0b38..a952804ff993 100644
> --- a/drivers/thermal/sun8i_thermal.c
> +++ b/drivers/thermal/sun8i_thermal.c
> @@ -512,9 +512,9 @@ static int sun8i_ths_probe(struct platform_device *pdev)
>          * registered yet, we deffer the registration of the interrupt to
>          * the end.
>          */
> -       ret = devm_request_threaded_irq(dev, irq, NULL,
> -                                       sun8i_irq_thread,
> -                                       IRQF_ONESHOT, "ths", tmdev);
> +       ret = devm_request_threaded_irq_probe(dev, irq, NULL,
> +                                             sun8i_irq_thread,
> +                                             IRQF_ONESHOT, "ths", tmdev, NULL);
>         if (ret)
>                 return ret;
>
> --
> 2.39.0
>