mm: introduce common STRUCT_PAGE_MAX_SHIFT define

This define is used by arm64 to calculate the size of the vmemmap
region.  It is defined as the log2 of the upper bound on the size of a
struct page.

We move it into mm_types.h so it can be defined properly instead of set
and checked with a build bug.  This also allows us to use the same
define for riscv.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Logan Gunthorpe <[email protected]>
Acked-by: Will Deacon <[email protected]>
Acked-by: Andrew Morton <[email protected]>
Acked-by: Ard Biesheuvel <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions