Re: [RFC][PATCH] linux/uuid.h: hoist uuid_is_null() helper from libnvdimm

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Wed, 2017-05-03 at 13:05 +0300, Amir Goldstein wrote:
> On Wed, May 3, 2017 at 12:13 PM, Andy Shevchenko
> <andriy.shevchenko@linux.intel.com> wrote:
> > On Tue, 2017-05-02 at 23:19 +0300, Amir Goldstein wrote:
> > > We need a helper for VFS to check if struct super_block field
> > > s_uuid
> > > was filled by the filesystem, before consumers can use it.
> > > 
> > > The libnvdimm code already has a private helper to check if uuid
> > > is
> > > null
> > > and the helper name is not using a private namespace prefix, which
> > > prevents us from using the same helper name as a common function.
> > > 
> > 
> > Hmm...
> > Have you checked my branch here:
> > https://bitbucket.org/andy-shev/linux/branch/topic%2Fuuid
> > ?
> > 
> 
> Hi Andy,
> 
> No I have not seen your patches. When do you plan to post them?

Some of them had been sent in different series recently and ~year ago.
Some need to be polished and tested first.

So, somewhere in the future for sure.

> > Probably not.
> > I have number of patches to make UUID API used kernel wide.
> > 
> 
> That looks nice, but I see you did not get to converting many other
> users that represent uuid as u8[16], like libnvdimm, bluetooth,
> various filesystems and users of sb->s_uuid (IMA).

Yes, my main goal is to make ACPI glue layer to use UUID API.

I didn't touch and I won't touch filesystems since it's a huge area
which I have no knowledge of.

For the rest I might be interested to do, but have no time.

> 
> > ...including helpers for null UUID check:
> > https://bitbucket.org/andy-shev/linux/commits/79029ebe2c32830f82effc
> > 0f0b
> > 62cce2b6eb7fdb?at=topic/uuid
> > 
> 
> I wouldn't mind using is_null_uuid_le(sb->s_uuid) myself and that is
> how
> I implemented the test in my current patch set, but I can hear the
> voices of
> those saying that there should be a 'natural' helper uuid_is_null(u8
> *) for the
> users that represent uuid as u8[16] (i.e. filesystems and sb->s_uuid).

u8 * doesn't represent UUID as a type.
Perhaps we need to reflect this in the name of the function somehow.

> Also, I suggest naming your helpers uuid_{le|be}_is_null() to maintain
> the uuid_* naming convention with other helpers you added to uuid.h.

I'm open to a name that satisfies most of us. So, no objections here.

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy