Re: [PATCH v4 01/21] genirq/devres: Add devm_request_threaded_irq_probe() and devm_request_irq_probe()
From: Jonathan Cameron
Date: Mon Jul 10 2023 - 08:41:49 EST
On Mon, 10 Jul 2023 14:25:24 +0200
Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> Hi Yangtao,
>
> On Mon, Jul 10, 2023 at 12:05 PM Yangtao Li <frank.li@xxxxxxxx> 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 add devm_request_threaded_irq_probe() and devm_request_irq_probe(),
> > 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@xxxxxxxxxxxxx>
> > Cc: Krzysztof Kozlowski <krzk@xxxxxxxxxx>
> > Cc: "Uwe Kleine-König" <u.kleine-koenig@xxxxxxxxxxxxxx>
> > Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> > Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> > Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
>
> Thanks for your patch!
>
> > --- a/include/linux/interrupt.h
> > +++ b/include/linux/interrupt.h
> > @@ -201,6 +201,21 @@ extern void free_percpu_nmi(unsigned int irq, void __percpu *percpu_dev_id);
> >
> > struct device;
> >
> > +extern int __must_check
> > +devm_request_threaded_irq_probe(struct device *dev, unsigned int irq,
> > + irq_handler_t handler, irq_handler_t thread_fn,
> > + unsigned long irqflags, const char *devname,
> > + void *dev_id, const char *info);
> > +
> > +static inline int __must_check
> > +devm_request_irq_probe(struct device *dev, unsigned int irq,
> > + irq_handler_t handler, unsigned long irqflags,
> > + const char *devname, void *dev_id, const char *info)
> > +{
> > + return devm_request_threaded_irq_probe(dev, irq, handler, NULL, irqflags,
> > + devname, dev_id, info);
> > +}
> > +
> > extern int __must_check
> > devm_request_threaded_irq(struct device *dev, unsigned int irq,
> > irq_handler_t handler, irq_handler_t thread_fn,
> > diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c
> > index f6e5515ee077..43a40d6e2e0b 100644
> > --- a/kernel/irq/devres.c
> > +++ b/kernel/irq/devres.c
> > @@ -79,6 +79,46 @@ int devm_request_threaded_irq(struct device *dev, unsigned int irq,
> > }
> > EXPORT_SYMBOL(devm_request_threaded_irq);
> >
> > +/**
> > + * devm_request_threaded_irq_probe - allocate an interrupt line for a managed device
It's awkward for the short description to be identical to devm_request_threaded_irq
but I can't think of a sensible and short way to differentiate it.
> > + * @dev: device to request interrupt for
> > + * @irq: Interrupt line to allocate
> > + * @handler: Function to be called when the IRQ occurs
> > + * @thread_fn: function to be called in a threaded interrupt context. NULL
> > + * for devices which handle everything in @handler
> > + * @irqflags: Interrupt type flags
> > + * @devname: An ascii name for the claiming device, dev_name(dev) if NULL
> > + * @dev_id: A cookie passed back to the handler function
> > + * @info: Optional additional error log
> > + *
> > + * This is a variant of the devm_request_threaded_irq function.
> > + * It will print an error message by default when the request fails,
> > + * and the consumer can add a special error msg.
> > + *
> > + * Except for the extra @dev argument, this function takes the
>
> ... extra @dev and @info arguments, ...
>
> > + * same arguments and performs the same function as
> > + * request_threaded_irq(). IRQs requested with this function will be
>
> But probably you want to compare with devm_request_threaded_irq()
> instead of with request_threaded_irq()?
> I.e. "... extra @info argument..." above.
>
> > + * automatically freed on driver detach.
> > + *
> > + * If an IRQ allocated with this function needs to be freed
> > + * separately, devm_free_irq() must be used.
> > + */
> > +int devm_request_threaded_irq_probe(struct device *dev, unsigned int irq,
> > + irq_handler_t handler, irq_handler_t thread_fn,
> > + unsigned long irqflags, const char *devname,
> > + void *dev_id, const char *info)
> > +{
> > + int rc;
> > +
> > + rc = devm_request_threaded_irq(dev, irq, handler, NULL, irqflags, devname, dev_id);
> > + if (rc)
> > + return dev_err_probe(dev, rc, "Failed to request %sinterrupt %u %s %s\n",
> > + thread_fn ? "threaded " : "", irq, devname ? : dev_name(dev),
> > + info ? : "");
> > + return 0;
> > +}
> > +EXPORT_SYMBOL(devm_request_threaded_irq_probe);
> > +
> > /**
> > * devm_request_any_context_irq - allocate an interrupt line for a managed device
> > * @dev: device to request interrupt for
>
> With the above fixed:
> Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Likewise, lgtm
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
I'd aim to get this upstream in one cycle with a few example drover changes
but if you plan to do mass changes, leave them for the following cycle to
make it really easy for maintainers to pick them up.
Jonathan
>
> Gr{oetje,eeting}s,
>
> Geert
>