[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>

9 files changed, 35 insertions, 0 deletions

diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index 3474309e049c..e3db1427dbe5 100644
--- a/arch/cris/Kconfig
+++ b/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
diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index 7561d7b72e75..cea237413aa2 100644
--- a/arch/frv/Kconfig
+++ b/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
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index 34a84bc4baf5..146eb28f6225 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -17,6 +17,10 @@ config SWAP
         bool
         default n
 
+config ZONE_DMA
+        bool
+        default y
+
 config FPU
         bool
         default n
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index f1d2899e9a62..549ead597934 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -24,6 +24,10 @@ config 64BIT
         bool
         default y
 
+config ZONE_DMA
+        bool
+        default y
+
 config MMU
         bool
         default y
diff --git a/arch/m68knommu/Kconfig b/arch/m68knommu/Kconfig
index 25993c2a8fbb..c5fc5406dad0 100644
--- a/arch/m68knommu/Kconfig
+++ b/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
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index eaed402ad346..c64973004261 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -7,6 +7,10 @@ config MMU
         bool
         default y
 
+config ZONE_DMA
+        bool
+        default y
+
 config LOCKDEP_SUPPORT
         bool
         default y
diff --git a/arch/v850/Kconfig b/arch/v850/Kconfig
index f0d4d72e560f..dbfab8fc9b49 100644
--- a/arch/v850/Kconfig
+++ b/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
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 2e74cb0b7807..7c99d518e49e 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -7,6 +7,10 @@ config FRAME_POINTER
         bool
         default n
 
+config ZONE_DMA
+        bool
+        default y
+
 config XTENSA
         bool
         default y
diff --git a/mm/Kconfig b/mm/Kconfig
index db7c55de92cd..50f7cfc15b78 100644
--- a/mm/Kconfig
+++ b/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
+
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