On Thu, Dec 20, 2018 at 11:23 AM Andrzej Hajda <a.ha...@samsung.com> 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.ha...@samsung.com>
> Reviewed-by: Javier Martinez Canillas <javi...@redhat.com>
> Reviewed-by: Mark Brown <broo...@kernel.org>
> Reviewed-by: Andy Shevchenko <andy.shevche...@gmail.com>
I'm not entirely convinced that the dev_err() log level is adequate
for this purpose, but anyway it looks like this may reduce code
duplication quite a bit, so
Reviewed-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
> ---
> v3:
> - added 'extern __printf(3, 4)' decorators to probe_err,
> - changed error logging format - newline at the end,
> - added empty lines in probe_err around dev_err,
> - added R-b by Mark and Andy.
> 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 | 39 +++++++++++++++++++++++++++++++++++++++
> include/linux/device.h | 3 +++
> 2 files changed, 42 insertions(+)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 0073b09bb99f..7f644f3c41d3 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -3099,6 +3099,45 @@ 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);
> +
> 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 6cb4640b6160..2d3a1cc6f5da 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -1591,6 +1591,9 @@ do {
> \
> WARN_ONCE(condition, "%s %s: " format, \
> dev_driver_string(dev), dev_name(dev), ## arg)
>
> +extern __printf(3, 4)
> +int probe_err(const struct device *dev, int err, const char *fmt, ...);
> +
> /* Create alias, so I can be autoloaded. */
> #define MODULE_ALIAS_CHARDEV(major,minor) \
> MODULE_ALIAS("char-major-" __stringify(major) "-" __stringify(minor))
> --
> 2.17.1
>
