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

[Yangtao Li]

On 2023/6/27 15:43, Krzysztof Kozlowski wrote:

> On 27/06/2023 09:16, Yangtao Li wrote:
> > 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.
> >
> > There are more than 700 calls to the devm_request_threaded_irq method.
> > If error messages are printed everywhere, more than 1000 lines of code
> > can be saved by removing the msg in the driver.
> >
> > Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
> > ---
> >   kernel/irq/devres.c | 5 ++++-
> >   1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/irq/devres.c b/kernel/irq/devres.c
> > index f6e5515ee077..94039a915218 100644
> > --- a/kernel/irq/devres.c
> > +++ b/kernel/irq/devres.c
> > @@ -58,8 +58,10 @@ int devm_request_threaded_irq(struct device *dev, unsigned int irq,
> >   
> >   	dr = devres_alloc(devm_irq_release, sizeof(struct irq_devres),
> >   			  GFP_KERNEL);
> > -	if (!dr)
> > +	if (!dr) {
> > +		dev_err(dev, "Failed to allocate device resource data\n");
> Just like any memory allocation, I don't think we print anything for
> devres failures. Why do you think we should start doing it?


And tglx point out that:

Having proper and consistent information why the device cannot be used 
_is_ useful.

> >   		return -ENOMEM;
> > +	}
> >   
> >   	if (!devname)
> >   		devname = dev_name(dev);
> > @@ -67,6 +69,7 @@ int devm_request_threaded_irq(struct device *dev, unsigned int irq,
> >   	rc = request_threaded_irq(irq, handler, thread_fn, irqflags, devname,
> >   				  dev_id);
> >   	if (rc) {
> > +		dev_err(dev, "Failed to request threaded irq\n");
> I don't like that one path - devm() managed - prints error, but regular
> path does not. Code should be here consistent. Also error message is too
> generic. You need to print at least irq number, maybe also devname?


v3 has been added.


Thx,

Yangtao


> Best regards,
> Krzysztof