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SubjectRe: [PATCH 15/17] powerpc: crypto: sysfs routines and docs for the nx device driver
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Hi Greg,

On Wed, 2012-03-21 at 15:11 -0700, Greg KH wrote:
> On Wed, Mar 21, 2012 at 04:41:20PM -0500, Kent Yoder wrote:
> > These routines add sysfs files supporting the Power7+ in-Nest encryption
> > accelerator driver.
> >
> > Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
> > ---
> > Documentation/powerpc/pfo-nx-crypto.txt | 52 ++++++++
>
> Please put sysfs file information in Documentation/ABI/ where it
> belongs.

Will do, I see debugfs docs in there too.

> Shouldn't the first just be debugfs files, as no "normal" user will ever
> care about such a thing?
>
> Actually, why are these sysfs files at all, how about all of this going
> into debugfs?

Yes, that's fine. These really are just for checking 'am I really
doing hardware encryption' and debugging any return codes that may come
back from the hcall. The error return is probably more easily dev_err'd
though.

>
> > +Error Detection
> > +===============
>
> <snip>
>
> What can anyone do with any of these files? What use are they to users?
>
> > +Device Use
> > +==========
>
> Again, what does a user care about these items for?
>
> > +int
> > +nx_sysfs_init(struct device_driver *drv)
> > +{
> > + int rc;
> > +
> > + rc = driver_create_file(drv, &driver_attr_aes_ops);
> > + if (rc)
> > + goto out;
>
> <snip>
>
> Oh, ${DIETY}, no. Please don't create files one by one, we do have
> functions that do all of this for you automatically, why aren't you
> using them?

Ok, I'll go look for some debugfs wrappers.

> > +void
> > +nx_sysfs_fini(struct device_driver *drv)
> > +{
> > + driver_remove_file(drv, &driver_attr_sync_ops);
> > + driver_remove_file(drv, &driver_attr_aes_bytes);
> > + driver_remove_file(drv, &driver_attr_aes_ops);
> > + driver_remove_file(drv, &driver_attr_sha256_bytes);
> > + driver_remove_file(drv, &driver_attr_sha256_ops);
> > + driver_remove_file(drv, &driver_attr_sha512_bytes);
> > + driver_remove_file(drv, &driver_attr_sha512_ops);
>
> Same here, don't do this, do it all at once.
>
> > +}
>
> Who is calling these functions? Where in the device lifecycle are the
> files being created? Did you just race userspace with how they are
> created, or are you doing it "properly"? (hint, odds are, as you are
> trying to manually create and remove these by hand, you aren't doing it
> properly...)

We're not racing here, other than with cat. Just so an admin can see
his workload is getting offloaded.

Thanks,
Kent

> thanks,
>
> greg k-h
>




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