x86, bitops: select the generic bitmap search functions

Introduce GENERIC_FIND_FIRST_BIT and GENERIC_FIND_NEXT_BIT in
lib/Kconfig, defaulting to off. An arch that wants to use the
generic implementation now only has to use a select statement
to include them.

I added an always-y option (X86_CPU) to arch/x86/Kconfig.cpu
and used that to select the generic search functions. This
way ARCH=um SUBARCH=i386 automatically picks up the change
too, and arch/um/Kconfig.i386 can therefore be simplified a
bit. ARCH=um SUBARCH=x86_64 does things differently, but
still compiles fine. It seems that a "def_bool y" always
wins over a "def_bool n"?

Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 5 insertions, 22 deletions

diff --git a/arch/um/Kconfig.i386 b/arch/um/Kconfig.i386
index 49990ea422e4..e09edfa560da 100644
--- a/arch/um/Kconfig.i386
+++ b/arch/um/Kconfig.i386
@@ -39,14 +39,6 @@ config ARCH_REUSE_HOST_VSYSCALL_AREA
         bool
         default y
 
-config GENERIC_FIND_FIRST_BIT
-        bool
-        default y
-
-config GENERIC_FIND_NEXT_BIT
-        bool
-        default y
-
 config GENERIC_HWEIGHT
         bool
         default y
diff --git a/arch/um/Kconfig.x86_64 b/arch/um/Kconfig.x86_64
index cc42e59585d2..5696e7b374b3 100644
--- a/arch/um/Kconfig.x86_64
+++ b/arch/um/Kconfig.x86_64
@@ -34,14 +34,6 @@ config SMP_BROKEN
         bool
         default y
 
-config GENERIC_FIND_FIRST_BIT
-        bool
-        default y
-
-config GENERIC_FIND_NEXT_BIT
-        bool
-        default y
-
 config GENERIC_HWEIGHT
         bool
         default y
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 700447738e73..2fadf794483d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -77,12 +77,6 @@ config GENERIC_BUG
         def_bool y
         depends on BUG
 
-config GENERIC_FIND_FIRST_BIT
-        def_bool y
-
-config GENERIC_FIND_NEXT_BIT
-        def_bool y
-
 config GENERIC_HWEIGHT
         def_bool y
 
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index cf3ff2c5cef2..7ef18b01f0bc 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -278,6 +278,11 @@ config GENERIC_CPU
 
 endchoice
 
+config X86_CPU
+        def_bool y
+        select GENERIC_FIND_FIRST_BIT
+        select GENERIC_FIND_NEXT_BIT
+
 config X86_GENERIC
         bool "Generic x86 support"
         depends on X86_32