[PATCH -next] riscv: TRANSPARENT_HUGEPAGE: depends on MMU

[Randy Dunlap <rdunlap@infradead.org>]

Fix a Kconfig warning and many build errors:

WARNING: unmet direct dependencies detected for COMPACTION
  Depends on [n]: MMU [=n]
  Selected by [y]:
  - TRANSPARENT_HUGEPAGE [=y] && HAVE_ARCH_TRANSPARENT_HUGEPAGE [=y]

and the subseqent thousands of build errors and warnings.

Fixes: e88b333142e4 ("riscv: mm: add THP support on 64-bit")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nanyong Sun <sunnanyong@huawei.com>
---
I really think that mm/Kconfig should have "depends on MMU" for
TRANSPARENT_HUGEPAGE, but commit 15626062f4a9 from 2012
("thp, x86: introduce HAVE_ARCH_TRANSPARENT_HUGEPAGE") thought
differently. I.e., mm/Kconfig should be protecting all arches
against this Kconfig problem.

 arch/riscv/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20210524.orig/arch/riscv/Kconfig
+++ linux-next-20210524/arch/riscv/Kconfig
@@ -106,7 +106,7 @@ config RISCV
 	select SYSCTL_EXCEPTION_TRACE
 	select THREAD_INFO_IN_TASK
 	select UACCESS_MEMCPY if !MMU
-	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
+	select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT && MMU
 
 config ARCH_MMAP_RND_BITS_MIN
 	default 18 if 64BIT