[PATCH] Set CONFIG_ZONE_DMA for arches with GENERIC_ISA_DMA

As Andi pointed out: CONFIG_GENERIC_ISA_DMA only disables the ISA DMA
channel management.  Other functionality may still expect GFP_DMA to
provide memory below 16M.  So we need to make sure that CONFIG_ZONE_DMA is
set independent of CONFIG_GENERIC_ISA_DMA.  Undo the modifications to
mm/Kconfig where we made ZONE_DMA dependent on GENERIC_ISA_DMA and set
theses explicitly in each arches Kconfig.

Reviews must occur for each arch in order to determine if ZONE_DMA can be
switched off.  It can only be switched off if we know that all devices
supported by a platform are capable of performing DMA transfers to all of
memory (Some arches already support this: uml, avr32, sh sh64, parisc and
IA64/Altix).

In order to switch ZONE_DMA off conditionally, one would have to establish
a scheme by which one can assure that no drivers are enabled that are only
capable of doing I/O to a part of memory, or one needs to provide an
alternate means of performing an allocation from a specific range of memory
(like provided by alloc_pages_range()) and insure that all drivers use that
call.  In that case the arches alloc_dma_coherent() may need to be modified
to call alloc_pages_range() instead of relying on GFP_DMA.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 84caf50725b53e829df2a39baa059084d63663e4..770f717bd250c2c0965b6477e2b6b205b8f37dbe 100644 (file)
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -41,6 +41,10 @@ config GENERIC_CALIBRATE_DELAY
        bool
        default y
 
+config ZONE_DMA
+       bool
+       default y
+
 config GENERIC_ISA_DMA
        bool
        default y

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 1523046e092bd6b24488354617293037ca47e0a6..fbf4b2a62b60ee9391b8fc8907b69c85d2d602ef 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -100,6 +100,10 @@ config GENERIC_BUST_SPINLOCK
 config ARCH_MAY_HAVE_PC_FDC
        bool
 
+config ZONE_DMA
+       bool
+       default y
+
 config GENERIC_ISA_DMA
        bool
 

diff --git a/arch/arm26/Kconfig b/arch/arm26/Kconfig
index 74eba8b5a8ca41c5576b30c691b56344f0a416ce..989113dce415fadb3ac3e4e6dff03ea40a2ebd7c 100644 (file)
--- a/arch/arm26/Kconfig
+++ b/arch/arm26/Kconfig
@@ -60,6 +60,10 @@ config GENERIC_CALIBRATE_DELAY
 config GENERIC_BUST_SPINLOCK
        bool
 
+config ZONE_DMA
+       bool
+       default y
+
 config GENERIC_ISA_DMA
        bool
 

diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 0dfee812811a9c75427551ef8177b45f2ca7a998..63d5e841caf5a1ce0ceb7e986c572b6b70f7f3e9 100644 (file)
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -38,6 +38,10 @@ config MMU
        bool
        default y
 
+config ZONE_DMA
+       bool
+       default y
+
 config SBUS
        bool
 

diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig
index f383dab973f5ea62d86f914a5774357be3ea7a4d..565d0138078e6f19a2475cea82aba61027ca75c9 100644 (file)
--- a/arch/m32r/Kconfig
+++ b/arch/m32r/Kconfig
@@ -16,6 +16,10 @@ config GENERIC_ISA_DMA
        bool
        default y
 
+config ZONE_DMA
+       bool
+       default y
+
 config GENERIC_HARDIRQS
        bool
        default y

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 70a577c89c7c84d279d9ce9f9c08f1c0bbaa08db..0bffbe6e7e1144b23f0a5c0a5c549a3bb8972b19 100644 (file)
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -439,6 +439,10 @@ config GENERIC_ISA_DMA
        depends on Q40 || AMIGA_PCMCIA || GG2
        default y
 
+config ZONE_DMA
+       bool
+       default y
+
 source "drivers/pci/Kconfig"
 
 source "drivers/zorro/Kconfig"

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 9d839a9c4b1a10f62b9f938e7ed013509a04178d..1bc6d249be4494d61a42a3e431d854664eac91f5 100644 (file)
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -8,6 +8,10 @@ mainmenu "Linux/MIPS Kernel Configuration"
 
 menu "Machine selection"
 
+config ZONE_DMA
+       bool
+       default y
+
 choice
        prompt "System type"
        default SGI_IP22

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index f08e80a0bf0addaf3a33d95f30238a6064f4a53e..0088c5ebca78190328a382ceebaa522ded7489b0 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -977,6 +977,10 @@ config ISA
          have an IBM RS/6000 or pSeries machine or a PReP machine, say Y.  If
          you have an embedded board, consult your board documentation.
 
+config ZONE_DMA
+       bool
+       default y
+
 config GENERIC_ISA_DMA
        bool
        depends on PPC64 || POWER4 || 6xx && !CPM2

diff --git a/arch/ppc/Kconfig b/arch/ppc/Kconfig
index c22e60619d9bb6c257f0b7a6483c355cf45112ea..0df9c33629fd992159cf95406157886dff090994 100644 (file)
--- a/arch/ppc/Kconfig
+++ b/arch/ppc/Kconfig
@@ -1177,6 +1177,10 @@ config ISA
          have an IBM RS/6000 or pSeries machine or a PReP machine, say Y.  If
          you have an embedded board, consult your board documentation.
 
+config ZONE_DMA
+       bool
+       default y
+
 config GENERIC_ISA_DMA
        bool
        depends on 6xx && !CPM2

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index d0dec1ea2eed93345091981a64c6028f9ae474ff..bd992c0048f0aa1d8801b6dde2b3380982268ef9 100644 (file)
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -13,6 +13,10 @@ config HIGHMEM
        bool
        default y
 
+config ZONE_DMA
+       bool
+       default y
+
 config GENERIC_ISA_DMA
        bool
        default y

diff --git a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
index d41f66ac7fff71dd8768271775aad6b183de987f..fb84647dbf3dedd132e4e0082a232ab95e9da0e4 100644 (file)
--- a/arch/sparc64/Kconfig
+++ b/arch/sparc64/Kconfig
@@ -232,6 +232,10 @@ config LARGE_ALLOCS
 
 source "mm/Kconfig"
 
+config ZONE_DMA
+       bool
+       default y
+
 config GENERIC_ISA_DMA
        bool
        default y

diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index d4275537b25b6e8bc814f19215278da2633420f3..02dd39457bcf20cfb487dc1d34833427d714cce3 100644 (file)
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -44,6 +44,10 @@ config MMU
        bool
        default y
 
+config ZONE_DMA
+       bool
+       default y
+
 config ISA
        bool
 

diff --git a/mm/Kconfig b/mm/Kconfig
index 79360cf519bfa86be803a2b890aab9e0a0b3ea40..7942b333e46cd46c11ac0f4a849c7b98efeee58e 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -139,10 +139,6 @@ 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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