Re: [RESEND PATCH v5 1/5] driver core: add probe_err log helper

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

On Wed, Jun 24, 2020 at 02:31:40PM +0200, Greg Kroah-Hartman wrote:
> On Wed, Jun 24, 2020 at 01:41:23PM +0200, Andrzej Hajda wrote:
> > During probe every time driver gets resource it should usually check for error
> > printk some message if it is not -EPROBE_DEFER and return the error. This
> > pattern is simple but requires adding few lines after any resource acquisition
> > code, as a result it is often omited or implemented only partially.
> > probe_err helps to replace such code sequences with simple call, so code:
> > 	if (err != -EPROBE_DEFER)
> > 		dev_err(dev, ...);
> > 	return err;
> > becomes:
> > 	return probe_err(dev, err, ...);
> > 
> > Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
> > Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
> > Reviewed-by: Mark Brown <broonie@kernel.org>
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> > ---
> >  drivers/base/core.c    | 39 +++++++++++++++++++++++++++++++++++++++
> >  include/linux/device.h |  3 +++
> >  2 files changed, 42 insertions(+)
> > 
> > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > index 67d39a90b45c..ee9da66bff1b 100644
> > --- a/drivers/base/core.c
> > +++ b/drivers/base/core.c
> > @@ -3953,6 +3953,45 @@ define_dev_printk_level(_dev_info, KERN_INFO);
> >  
> >  #endif
> >  
> > +/**
> > + * probe_err - probe error check and log helper
> > + * @dev: the pointer to the struct device
> > + * @err: error value to test
> > + * @fmt: printf-style format string
> > + * @...: arguments as specified in the format string
> > + *
> > + * This helper implements common pattern present in probe functions for error
> > + * checking: print message if the error is not -EPROBE_DEFER and propagate it.
> > + * It replaces code sequence:
> > + * 	if (err != -EPROBE_DEFER)
> > + * 		dev_err(dev, ...);
> > + * 	return err;
> > + * with
> > + * 	return probe_err(dev, err, ...);
> > + *
> > + * Returns @err.
> > + *
> > + */
> > +int probe_err(const struct device *dev, int err, const char *fmt, ...)
> > +{
> > +	struct va_format vaf;
> > +	va_list args;
> > +
> > +	if (err == -EPROBE_DEFER)
> > +		return err;
> > +
> > +	va_start(args, fmt);
> > +	vaf.fmt = fmt;
> > +	vaf.va = &args;
> > +
> > +	dev_err(dev, "error %d: %pV", err, &vaf);
> > +
> > +	va_end(args);
> > +
> > +	return err;
> > +}
> > +EXPORT_SYMBOL_GPL(probe_err);
> 
> Please be specific in global symbols, how about "driver_probe_error()"?

Or dev_err_probe() to match the existing dev_* functions ?

> And merge the other patch into this one, as Raphael said, otherwise this
> just looks odd to add something and then fix it up later.

-- 
Regards,

Laurent Pinchart