Re: [PATCH] debugfs: add get/set for atomic types

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

On Fri, Oct 26, 2012 at 01:46:38PM -0500, Seth Jennings wrote:
> On 10/26/2012 11:13 AM, Greg Kroah-Hartman wrote:
> > On Fri, Oct 26, 2012 at 10:49:01AM -0500, Seth Jennings wrote:
> >> debugfs currently lacks the ability to create attributes
> >> that set/get atomic_t values.
> >>
> >> This patch adds support for this through a new
> >> debugfs_create_atomic_t() function.
> > 
> > Why would you want to set an atomic variable type from userspace?
> 
> In my particular use case, I'm not setting from userspace, only getting.

That's good, you wouldn't want to set an atomic from userspace.

> All the other types are symmetric, being both settable and gettable,
> so I was just trying to blend with the other types.

Fair enough.

> > What in-kernel code needs this?
> 
> None, yet.  I am working on code that does.
> 
> If you would rather me send this as part of the patchset for that
> code, I can.  I just wanted to get this in early if I could since it
> is functionality I can see others using.
> 
> For an example, see drivers/staging/ramster/zcache-main.c:132 where
> both atomic and non-atomic version of stats are being maintained so
> that the non-atomic version can be read by debugfs.
> 
> Beside not having an in-kernel user yet, does this approach look good
> to you?

It looks reasonable, but please hold off and submit this as part of a
patch series that needs it.  No need to add it now.

thanks,

greg k-h