slub: use size and objsize orders to disable debug flags

slub: use size and objsize orders to disable debug flags

This patch moves the masking of debugging flags which increase a cache's
min order due to metadata when `slub_debug=O' is used from
kmem_cache_flags() to kmem_cache_open().

Instead of defining the maximum metadata size increase in a preprocessor
macro, this approach uses the cache's ->size and ->objsize members to
determine if the min order increased due to debugging options.  If so,
the flags specified in the more appropriately named DEBUG_METADATA_FLAGS
are masked off.

This approach was suggested by Christoph Lameter
<[email protected]>.

Cc: Christoph Lameter <[email protected]>
Signed-off-by: David Rientjes <[email protected]>
Signed-off-by: Pekka Enberg <[email protected]>