Commit a787e540 authored by Andrzej Hajda's avatar Andrzej Hajda Committed by Greg Kroah-Hartman
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driver core: add device probe log helper 



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 omitted or implemented only
partially.
dev_err_probe helps to replace such code sequences with simple call,
so code:
	if (err != -EPROBE_DEFER)
		dev_err(dev, ...);
	return err;
becomes:
	return dev_err_probe(dev, err, ...);

Signed-off-by: default avatarAndrzej Hajda <a.hajda@samsung.com>
Reviewed-by: default avatarRafael J. Wysocki <rafael@kernel.org>
Reviewed-by: default avatarMark Brown <broonie@kernel.org>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200713144324.23654-2-a.hajda@samsung.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 65488832

drivers/base/core.c

+42 −0
Original line number Diff line number Diff line
@@ -4203,6 +4203,48 @@ define_dev_printk_level(_dev_info, KERN_INFO); 


#endif



/**

 * dev_err_probe - 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 debug or error message depending if the error value is

 * -EPROBE_DEFER and propagate error upwards.

 * It replaces code sequence:

 * 	if (err != -EPROBE_DEFER)

 * 		dev_err(dev, ...);

 * 	else

 * 		dev_dbg(dev, ...);

 * 	return err;

 * with

 * 	return dev_err_probe(dev, err, ...);

 *

 * Returns @err.

 *

 */

int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)

{

	struct va_format vaf;

	va_list args;



	va_start(args, fmt);

	vaf.fmt = fmt;

	vaf.va = &args;



	if (err != -EPROBE_DEFER)

		dev_err(dev, "error %d: %pV", err, &vaf);

	else

		dev_dbg(dev, "error %d: %pV", err, &vaf);



	va_end(args);



	return err;

}

EXPORT_SYMBOL_GPL(dev_err_probe);



static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)

{

	return fwnode && !IS_ERR(fwnode->secondary);

include/linux/device.h

+3 −0
Original line number Diff line number Diff line
@@ -962,6 +962,9 @@ void device_link_remove(void *consumer, struct device *supplier); 
void device_links_supplier_sync_state_pause(void);

void device_links_supplier_sync_state_resume(void);



extern __printf(3, 4)

int dev_err_probe(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))

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