Re: [PATCH v3 2/5] thermal/drivers/armada: convert to use devm_request_threaded_irq_emsg()

Uwe Kleine-König
2023-07-04T14:22:49Z

[-- Attachment #1: Type: text/plain, Size: 3725 bytes --]

Hello Miquel,

On Tue, Jul 04, 2023 at 10:46:08AM +0200, Miquel Raynal wrote:
> Hi Yangtao,
>
> frank.li@vivo.com wrote on Mon, 3 Jul 2023 17:04:51 +0800:
>
> > There are more than 700 calls to the devm_request_threaded_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 1000 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.
> >
> > Let's use devm_request_threaded_irq_emsg(), 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>
> > Signed-off-by: Yangtao Li <frank.li@vivo.com>
> > ---
> > drivers/thermal/armada_thermal.c | 13 +++++--------
> > 1 file changed, 5 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/thermal/armada_thermal.c b/drivers/thermal/armada_thermal.c
> > index 9f6dc4fc9112..a5e140643f00 100644
> > --- a/drivers/thermal/armada_thermal.c
> > +++ b/drivers/thermal/armada_thermal.c
> > @@ -913,15 +913,12 @@ static int armada_thermal_probe(struct platform_device *pdev)
> >
> > /* The overheat interrupt feature is not mandatory */
> > if (irq > 0) {
> > - ret = devm_request_threaded_irq(&pdev->dev, irq,
> > - armada_overheat_isr,
> > - armada_overheat_isr_thread,
> > - 0, NULL, priv);
> > - if (ret) {
> > - dev_err(&pdev->dev, "Cannot request threaded IRQ %d\n",
> > - irq);
> > + ret = devm_request_threaded_irq_emsg(&pdev->dev, irq,
> > + armada_overheat_isr,
> > + armada_overheat_isr_thread,
> > + 0, NULL, priv, NULL);
> > + if (ret)
>
> I don't see a patch renaming this helper with s/emsg//, do you plan to
> keep it like that? I bet nobody outside of this series will notice the
> new helper and will continue to add error messages because it kind
> of feels "right" to do so.
>
> I would rather prefer returning to the original function name which
> everybody knows/uses.

See https://lore.kernel.org/lkml/87h6qpyzkd.ffs@tglx for why there is a
new function name.

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]