[PATCH v4 05/21] thermal/drivers/tegra: convert to use devm_request*_irq_probe()

[PATCH v4 05/21] thermal/drivers/tegra: convert to use devm_request*_irq_probe()

[Yangtao Li]

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@linutronix.de>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
Cc: AngeloGioacchino Del Regno  <angelogioacchino.delregno@collabora.com>
Signed-off-by: Yangtao Li <frank.li@vivo.com>
---
 drivers/thermal/tegra/soctherm.c        | 38 ++++++++++++-------------
 drivers/thermal/tegra/tegra30-tsensor.c |  9 +++---
 2 files changed, 22 insertions(+), 25 deletions(-)

diff --git a/drivers/thermal/tegra/soctherm.c b/drivers/thermal/tegra/soctherm.c
index ea66cba09e56..3d144377d90a 100644
--- a/drivers/thermal/tegra/soctherm.c
+++ b/drivers/thermal/tegra/soctherm.c
@@ -1993,29 +1993,27 @@ static int soctherm_interrupts_init(struct platform_device *pdev,
 		return 0;
 	}
 
-	ret = devm_request_threaded_irq(&pdev->dev,
-					tegra->thermal_irq,
-					soctherm_thermal_isr,
-					soctherm_thermal_isr_thread,
-					IRQF_ONESHOT,
-					dev_name(&pdev->dev),
-					tegra);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "request_irq 'thermal_irq' failed.\n");
+	ret = devm_request_threaded_irq_probe(&pdev->dev,
+					      tegra->thermal_irq,
+					      soctherm_thermal_isr,
+					      soctherm_thermal_isr_thread,
+					      IRQF_ONESHOT,
+					      dev_name(&pdev->dev),
+					      tegra,
+					      "thermal_irq");
+	if (ret < 0)
 		return ret;
-	}
 
-	ret = devm_request_threaded_irq(&pdev->dev,
-					tegra->edp_irq,
-					soctherm_edp_isr,
-					soctherm_edp_isr_thread,
-					IRQF_ONESHOT,
-					"soctherm_edp",
-					tegra);
-	if (ret < 0) {
-		dev_err(&pdev->dev, "request_irq 'edp_irq' failed.\n");
+	ret = devm_request_threaded_irq_probe(&pdev->dev,
+					      tegra->edp_irq,
+					      soctherm_edp_isr,
+					      soctherm_edp_isr_thread,
+					      IRQF_ONESHOT,
+					      "soctherm_edp",
+					      tegra,
+					      "edp_irq");
+	if (ret < 0)
 		return ret;
-	}
 
 	return 0;
 }
diff --git a/drivers/thermal/tegra/tegra30-tsensor.c b/drivers/thermal/tegra/tegra30-tsensor.c
index c243e9d76d3c..dd4c2deba93a 100644
--- a/drivers/thermal/tegra/tegra30-tsensor.c
+++ b/drivers/thermal/tegra/tegra30-tsensor.c
@@ -593,12 +593,11 @@ static int tegra_tsensor_probe(struct platform_device *pdev)
 			return err;
 	}
 
-	err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
-					tegra_tsensor_isr, IRQF_ONESHOT,
-					"tegra_tsensor", ts);
+	err = devm_request_threaded_irq_probe(&pdev->dev, irq, NULL,
+					      tegra_tsensor_isr, IRQF_ONESHOT,
+					      "tegra_tsensor", ts, NULL);
 	if (err)
-		return dev_err_probe(&pdev->dev, err,
-				     "failed to request interrupt\n");
+		return err;
 
 	return 0;
 }
-- 
2.39.0

Re: [PATCH v4 05/21] thermal/drivers/tegra: convert to use devm_request*_irq_probe()

[Thierry Reding]

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On Mon, Jul 10, 2023 at 05:59:09PM +0800, 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.

Do we really need to keep repeating this same commit message for each
and everyone of these commits? It's already in the cover letter and
presumably on the patch that introduces the new helper, so surely we can
come up with a denser version for individual subsystem patches.

Other than that this looks good:

Acked-by: Thierry Reding <treding@nvidia.com>

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Re: [PATCH v4 05/21] thermal/drivers/tegra: convert to use devm_request*_irq_probe()

[Krzysztof Kozlowski]

On 10/07/2023 15:16, Thierry Reding wrote:
> On Mon, Jul 10, 2023 at 05:59:09PM +0800, 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.
> 
> Do we really need to keep repeating this same commit message for each
> and everyone of these commits? It's already in the cover letter and
> presumably on the patch that introduces the new helper, so surely we can
> come up with a denser version for individual subsystem patches.

Yeah, this is way too long to put in every commit doing the same but for
different drivers.

Best regards,
Krzysztof