slub: Add cmpxchg_double_slab()

Add a function that operates on the second doubleword in the page struct
and manipulates the object counters, the freelist and the frozen attribute.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --cc include/linux/slub_def.h
Simple merge

diff --cc mm/slub.c
Simple merge