From: Greg KH <gregkh@linuxfoundation.org>
Date: Thu, 13 Feb 2014 16:03:20 -0800

So how about just "open coding" a kref for this structure, as it wants
something that doesn't fit into the kref model, and should be pretty
simple to do (you can ensure you get the locking right, unlike almost
all users of krefs, as Al Viro constantly points out to me...)

They redid their patches meanwhile to use their own atomic_t.