linux-kernel - Re: [PATCH v1 1/1] sysctl: introduce uuid_le and uuid

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Date:	Tue, 24 May 2016 23:25:30 +0300
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Theodore Ts'o <tytso@....edu>, Arnd Bergmann <arnd@...db.de>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/1] sysctl: introduce uuid_le and uuid_be

On Tue, 2016-05-24 at 13:15 -0700, Andrew Morton wrote:
> On Tue, 24 May 2016 20:27:27 +0300 Andy Shevchenko <andriy.shevchenko@
> linux.intel.com> wrote:
> 
> > By default the sysctl interface returns random UUID in big endian
> > format.
> > Sometimes it's not suitable, e.g. using generated UUID for EFI
> > variable name.
> > Provide uuid_le and uuid_be to comprehence that interface.
> > 
> > ...
> > 
> >  drivers/char/random.c       | 44
> > +++++++++++++++++++++++++++++++++++++++++
> >  include/uapi/linux/sysctl.h |  4 +++-
> >  kernel/sysctl_binary.c      | 48
> > ++++++++++++++++++++++++++++++++++++++++++++
> 
> Why does the kernel need to do this?  If userspace wants a random uuid
> then it can grab a random number and cook up the UUID itself.

Good question. I dunno why we have uuid in the first place there. At
some point I noticed people who recommend to use that file to get a
random UUID(s), but apparently they don't aware that endianess matters. 

P.S. I thought to send this as RFC, but decided to drop the notation in
last minute. So, it's okay to drop it.

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