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SubjectRe: [PATCH v2 01/15] genirq/devres: Add error information printing for devm_request_threaded_irq()
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Hi,

On 2023/6/30 19:11, Thomas Gleixner wrote:
> On Tue, Jun 27 2023 at 13:00, Uwe Kleine-König wrote:
>> On Tue, Jun 27, 2023 at 06:12:01PM +0800, Yangtao Li wrote:
>>
>> While I assume changing to dev_err_probe is a result of my concern that
>> no error should be printed when rc=-EPROBEDEFER, my other concern that
>> adding an error message to a generic allocation function is a bad idea
>> still stands.
> I agree in general, but if you 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.
>
> Yangtao: The way how this is attempted is not useful at all.
>
> 1) The changelog is word salad and provides 0 rationale
>
> Also such series require a cover letter...
>
> 2) The dev_err() which is added is not informative at all and cannot
> replace actually useful error messages. It's not that hard to
> make it useful.
>
> 2) Adding the printks unconditionally first will emit two messages
> with different content.
>
> This is not how such changes are done.
>
> The proper approach is to create a wrapper function which emits
> the error message:
>
> wrapper(....., const char *info)
> {
> ret = devm_request_threaded_irq(....);
> if (ret < 0) {
> dev_err(dev, "Failed to request %sinterrupt %u %s %s: %d\n,
> thread_fn ? "threaded " : "",
> irq, devname, info ? : "", ret);
> }
> return ret;
> }
>
> Then convert the callsites over one by one with proper
> changelogs and justification.
>
> See?


Yes, thanks a lot for the suggestion, and v3 has been sent.


MBR,

Yangtao


>
> Thanks,
>
> tglx

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