On 16.10.2018 13:29, Andrzej Hajda wrote:
> On 16.10.2018 13:01, Andy Shevchenko wrote:
>> On Tue, Oct 16, 2018 at 10:22 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 seqences 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>
>>> ---
>>> 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..23fabefb217a 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
>>> + * @...: 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) {
>> Why not
>>
>> if (err == ...)
>> return err;
>>
>> ...
>> return err;
>>
>> ?
>>
>> Better to read, better to maintain. No?
> Yes, anyway next patch will re-factor it anyway.
>
>>> + va_start(args, fmt);
>>> +
>>> + vaf.fmt = fmt;
>>> + vaf.va = &args;
>>> +
>>> + __dev_printk(KERN_ERR, dev, &vaf);
>> It would be nice to print an error code as well, wouldn't it?
> Hmm, on probe fail error is printed anyway (with exception of
> EPROBE_DEFER, ENODEV and ENXIO):
> "probe of %s failed with error %d\n"
> On the other side currently some drivers prints the error code anyway
> via dev_err or similar, so I guess during conversion to probe_err it
> should be removed then.
>
> If we add error code to probe_err is it OK to report it this way?
> dev_err(dev, "%V, %d\n", &vaf, err);
Ups, I forgot that message passed to probe_err will contain already
newline character.
So the err must be before message passed to probe_err, for example:
dev_err(dev, "err=%d: %V\n", err, &vaf);
Is it OK? Or better leave this part of the patch as is?
Regards
Andrzej
>
> Regards
> Andrzej
>
>>> + va_end(args);
>>> + }
>>> +
>>> + return 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, ...);
>>> +
>>> /* Create alias, so I can be autoloaded. */
>>> #define MODULE_ALIAS_CHARDEV(major,minor) \
>>> MODULE_ALIAS("char-major-" __stringify(major) "-"
>>> __stringify(minor))
>>> --
>>> 2.18.0
>>>
