[PATCH] optional ZONE_DMA: introduce CONFIG_ZONE_DMA

This patch simply defines CONFIG_ZONE_DMA for all arches.  We later do special
things with CONFIG_ZONE_DMA after the VM and an arch are prepared to work
without ZONE_DMA.

CONFIG_ZONE_DMA can be defined in two ways depending on how an architecture
handles ISA DMA.

First if CONFIG_GENERIC_ISA_DMA is set by the arch then we know that the arch
needs ZONE_DMA because ISA DMA devices are supported.  We can catch this in
mm/Kconfig and do not need to modify arch code.

Second, arches may use ZONE_DMA in an unknown way.  We set CONFIG_ZONE_DMA for
all arches that do not set CONFIG_GENERIC_ISA_DMA in order to insure backwards
compatibility.  The arches may later undefine ZONE_DMA if their arch code has
been verified to not depend on ZONE_DMA.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/cris/Kconfig

@@ -9,6 +9,10 @@ config MMU
 	bool
 	default y
 
+config ZONE_DMA
+	bool
+	default y
+
 config RWSEM_GENERIC_SPINLOCK
 	bool
 	default y

arch/frv/Kconfig

@@ -6,6 +6,10 @@ config FRV
 	bool
 	default y
 
+config ZONE_DMA
+	bool
+	default y
+
 config RWSEM_GENERIC_SPINLOCK
 	bool
 	default y

arch/h8300/Kconfig

@@ -17,6 +17,10 @@ config SWAP
 	bool
 	default n
 
+config ZONE_DMA
+	bool
+	default y
+
 config FPU
 	bool
 	default n

arch/ia64/Kconfig

@@ -24,6 +24,10 @@ config 64BIT
 	bool
 	default y
 
+config ZONE_DMA
+	bool
+	default y
+
 config MMU
 	bool
 	default y

arch/m68knommu/Kconfig

@@ -17,6 +17,10 @@ config FPU
 	bool
 	default n
 
+config ZONE_DMA
+	bool
+	default y
+
 config RWSEM_GENERIC_SPINLOCK
 	bool
 	default y

arch/s390/Kconfig

@@ -7,6 +7,10 @@ config MMU
 	bool
 	default y
 
+config ZONE_DMA
+	bool
+	default y
+
 config LOCKDEP_SUPPORT
 	bool
 	default y

arch/v850/Kconfig

@@ -10,6 +10,9 @@ mainmenu "uClinux/v850 (w/o MMU) Kernel Configuration"
 config MMU
        	bool
 	default n
+config ZONE_DMA
+	bool
+	default y
 config RWSEM_GENERIC_SPINLOCK
 	bool
 	default y

arch/xtensa/Kconfig

@@ -7,6 +7,10 @@ config FRAME_POINTER
 	bool
 	default n
 
+config ZONE_DMA
+	bool
+	default y
+
 config XTENSA
 	bool
 	default y

mm/Kconfig

@@ -139,6 +139,10 @@ config SPLIT_PTLOCK_CPUS
 	default "4096" if PARISC && !PA20
 	default "4"
 
+config ZONE_DMA
+	def_bool y
+	depends on GENERIC_ISA_DMA
+
 #
 # support for page migration
 #