[PATCH 0/2] Introduce kref_sub

[Thomas Hellstrom]

Adding a function in order to be able to optimize away a number of locked
bus cycles. Callers might for whatever reason want to accumulate unreferences
in certain code paths (rcu grace periods, atomic regions ...). This makes
it possible to perform the batched unreference more efficiently.

If accepted, I'd prefer patch 1 goes through Dave's DRM tree.