Re: [PATCH v2 1/2] driver core: class: expose the class kobject

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Oct 15, 2024 at 10:00:23AM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> Export the address of the /sys/class kobject to users that need to
> chain off of it by means other than calling register_class().

Ick, no.

> This will
> be used by the GPIO subsystem to provide a backward compatibility
> mount-point for the GPIO sysfs class once it's disabled.

Again, ick, no.

No "mount point" should be messing with sysfs, don't do that.

sysfs is a simple "if the file or directory is not there, don't worry
about it" type of interface (i.e. fixing the issues we had with /proc).
If a userspace tool can't find something there, then it should just
error out or move on.

Let's not allow anything to mount anything at /sys/class/ please, that
way lies madness for the next 40+ years.  If you want to drop a
userspace api, drop it, don't paper over it with something that you
can't drop either.

thanks,

greg k-h