[PATCH 1/8] thp, x86: introduce HAVE_ARCH_TRANSPARENT_HUGEPAGE

[Gerald Schaefer <gerald.schaefer@de.ibm.com>]

Cleanup patch in preparation for transparent hugepage support on s390.
Adding new architectures to the TRANSPARENT_HUGEPAGE config option can
make the "depends" line rather ugly, like "depends on
(X86 || (S390 && 64BIT)) && MMU".
This patch adds a HAVE_ARCH_TRANSPARENT_HUGEPAGE instead. x86 already
has MMU "def_bool y", so the MMU check is superfluous there and
HAVE_ARCH_TRANSPARENT_HUGEPAGE can be selected in arch/x86/Kconfig.

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
---
 arch/Kconfig     | 3 +++
 arch/x86/Kconfig | 1 +
 mm/Kconfig       | 2 +-
 3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 72f2fa1..04de2d2 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -281,4 +281,7 @@ config SECCOMP_FILTER
 
 	  See Documentation/prctl/seccomp_filter.txt for details.
 
+config HAVE_ARCH_TRANSPARENT_HUGEPAGE
+	bool
+
 source "kernel/gcov/Kconfig"
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 8ec3a1a..0b9bb7b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -97,6 +97,7 @@ config X86
 	select KTIME_SCALAR if X86_32
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER
+	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 
 config INSTRUCTION_DECODER
 	def_bool (KPROBES || PERF_EVENTS || UPROBES)
diff --git a/mm/Kconfig b/mm/Kconfig
index d5c8019..3322342 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -318,7 +318,7 @@ config NOMMU_INITIAL_TRIM_EXCESS
 
 config TRANSPARENT_HUGEPAGE
 	bool "Transparent Hugepage Support"
-	depends on X86 && MMU
+	depends on HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select COMPACTION
 	help
 	  Transparent Hugepages allows the kernel to use huge pages and
-- 
1.7.11.5