slab: Return NULL for oversized allocations

slab: Return NULL for oversized allocations

The inline path seems to have changed the SLAB behavior for very large
kmalloc allocations with  commit e3366016 ("slab: Use common
kmalloc_index/kmalloc_size functions"). This patch restores the old
behavior but also adds diagnostics so that we can figure where in the
code these large allocations occur.

Reported-and-tested-by: Tetsuo Handa <[email protected]>
Signed-off-by: Christoph Lameter <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ [email protected]: use WARN_ON_ONCE ]
Signed-off-by: Pekka Enberg <[email protected]>