Re: [PATCH v2 1/4] scsi: ufs: Add Configuration Descriptor to sysfs

From: Evan Green
Date: Mon Jun 18 2018 - 12:55:01 EST


On Sat, Jun 16, 2018 at 12:16 AM Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Fri, Jun 15, 2018 at 02:00:46PM -0700, Evan Green wrote:
> > This change adds the configuration descriptor to the UFS
> > sysfs interface. This is done in preparation for making the
> > interface writable, which will enable provisioning UFS devices
> > via Linux.
> >
> > The configuration descriptor is laid out as a header, then a set of
> > (usually 8) copies of the same descriptor for each unit.
> >
> > Signed-off-by: Evan Green <evgreen@xxxxxxxxxxxx>
> > ---
> > Changes since v1:
> > - Squashed documentation changes into this change.
> > - Reworked sysfs layout so that instead of a sysfs file for a
> > unit selector and then a common set of unit attributes, each unit in
> > the config descriptor has its own directory. This required a little
> > bit of kobject magic. Alternatively I could use standard device
> > attributes and simply allocate N*M of them from a template. I have
> > that coded up, and can go with that if preferred, but I thought
> > this was a little nicer since it wasted less memory.
>
> Ick, don't use "raw" kobjects please, as userspace will not see them
> correctly in the libraries that track devices and attributes, like
> libudev.
>
> And what is wrong with using configfs? I thought that was the better
> way to go for something like this. You are configuring the device,
> which is exactly what configfs was created for, to keep people from
> having to do this type of mess in sysfs.
>
> thanks,
>
> greg k-h

Ok. Sayali's got patches for doing this via configfs, so let's go with his.
-Evan