[v4,01/21] genirq/devres: Add devm_request_threaded_irq_probe() and devm_request_irq_probe()

  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@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>
---
 include/linux/interrupt.h | 15 +++++++++++++++
 kernel/irq/devres.c       | 40 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
  

On 10/07/2023 11:59, 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.
> 
> 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>
> ---


Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof
  

Hi Yangtao,

On Mon, Jul 10, 2023 at 12:05 PM Yangtao Li <frank.li@vivo.com> 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@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>

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
> + *     @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@glider.be>

Gr{oetje,eeting}s,

                        Geert
  

On Mon, 10 Jul 2023 14:25:24 +0200
Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> Hi Yangtao,
> 
> On Mon, Jul 10, 2023 at 12:05 PM Yangtao Li <frank.li@vivo.com> 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@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>  
> 
> 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@glider.be>

Likewise, lgtm
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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
>