On Wed, Oct 17, 2018 at 10:58:24AM +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 <[email protected]>
> Reviewed-by: Javier Martinez Canillas <[email protected]>
> 
> ---
> v2:
>   - added error value to log message,
>   - fixed code style,
>   - added EXPORT_SYMBOL_GPL,
>   - Added R-B by Javier (I hope the changes did not invalidate it).
> ---
>  drivers/base/core.c    | 37 +++++++++++++++++++++++++++++++++++++
>  include/linux/device.h |  2 ++
>  2 files changed, 39 insertions(+)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 04bbcd779e11..aa6f3229d066 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -3067,6 +3067,43 @@ 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, not ended with newline
> + * @...: 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, "%pV, %d\n", &vaf, err);
> +     va_end(args);
> +
> +     return err;
> +}
> +EXPORT_SYMBOL_GPL(probe_err);
> +
>  static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
>  {
>       return fwnode && !IS_ERR(fwnode->secondary);
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 90224e75ade4..06c2c797d132 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -1577,6 +1577,8 @@ do {                                                    
>                 \
>       WARN_ONCE(condition, "%s %s: " format, \
>                       dev_driver_string(dev), dev_name(dev), ## arg)
>  
> +int probe_err(const struct device *dev, int err, const char *fmt, ...);

__printf(3, 4) ?

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