mm: introduce common STRUCT_PAGE_MAX_SHIFT define
authorLogan Gunthorpe <logang@deltatee.com>
Fri, 14 Dec 2018 22:16:53 +0000 (14:16 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 14 Dec 2018 23:05:45 +0000 (15:05 -0800)
commitd1402fc708e4c355813e49df6d15bc3466ba5114
treefab18217bc25d21ed1a1b507cdf427d1c69b5db4
parent5b5260902af4cf7d2b8da06ba395a722f6d490fa
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/20181107205433.3875-2-logang@deltatee.com
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/arm64/include/asm/memory.h
arch/arm64/mm/init.c
include/asm-generic/fixmap.h
include/linux/mm_types.h