Re: [PATCH 2/2] sysfs: add devm_sysfs_create_group() and friends

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Tue, Jul 18, 2017 at 10:03:36PM +0200, Greg Kroah-Hartman wrote:
> On Tue, Jul 18, 2017 at 12:30:58PM -0700, Dmitry Torokhov wrote:
> > --- a/include/linux/sysfs.h
> > +++ b/include/linux/sysfs.h
> > @@ -282,6 +282,16 @@ int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
> >  				      struct kobject *target_kobj,
> >  				      const char *target_name);
> >  
> > +struct device;
> 
> Put this in device.h instead?

I think we normally keep devm* and non-managed APIs together, like both
regulator*() and devm_regulator*() are in include/linux/regulator/consumer.h,
gpiod*() and devm_gpiod*() are in include/gpio/linux/consumer.h,
clk*() and devm_clk() are in include/linux/clk.h, and so forth.

I think there is benefit of having these together as well.

> 
> > +int __must_check devm_sysfs_create_group(struct device *dev,
> > +				const struct attribute_group *grp);
> > +int __must_check devm_sysfs_create_groups(struct device *dev,
> > +				const struct attribute_group **groups);
> > +void devm_sysfs_remove_group(struct device *dev,
> > +			     const struct attribute_group *grp);
> > +void devm_sysfs_remove_groups(struct device *dev,
> > +			      const struct attribute_group **groups);
> 
> I have finally moved the driver core to only accept/need "groups" not a
> single "group", so we should only need devm_sysfs_create_groups and
> devm_sysfs_remove_groups, right?

This makes total sense for the driver core, but individual drivers
usually have a single group. Requiring all of them to have array of
groups just adds unneeded boilerplate that I was trying to cut down.

> 
> And do we need/want the non-devm versions:
> 	device_create_groups()
> 	device_remove_groups()
> ?

We already have non-managed sysfs_create_groups() and
sysfs_remove_groups().

> 
> And you can probably drop the 'sysfs' from the function name if you
> want.

I think there is benefit of having devm version having name matching the
non-managed one:

sysfs_create_groups() and devm_sysfs_create_groups().

I hope you will reconsider.

Thanks!

-- 
Dmitry