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

    Thanks,

    tglx

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