+ documentation-dma-api-howto-add-arch_kmalloc_minalign-description.patch added to -mm tree

[akpm@linux-foundation.org]

The patch titled
     Documentation/DMA-API-HOWTO: add ARCH_KMALLOC_MINALIGN description
has been added to the -mm tree.  Its filename is
     documentation-dma-api-howto-add-arch_kmalloc_minalign-description.patch

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------------------------------------------------------
Subject: Documentation/DMA-API-HOWTO: add ARCH_KMALLOC_MINALIGN description
From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

Add ARCH_KMALLOC_MINALIGN description in "Platform Issues" section.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/DMA-API-HOWTO.txt |   15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff -puN Documentation/DMA-API-HOWTO.txt~documentation-dma-api-howto-add-arch_kmalloc_minalign-description Documentation/DMA-API-HOWTO.txt
--- a/Documentation/DMA-API-HOWTO.txt~documentation-dma-api-howto-add-arch_kmalloc_minalign-description
+++ a/Documentation/DMA-API-HOWTO.txt
@@ -738,7 +738,20 @@ to "Closing".
    CONFIG_NEED_SG_DMA_LENGTH if the architecture supports IOMMUs
    (including software IOMMU).
 
-2) More to come...
+2) ARCH_KMALLOC_MINALIGN
+
+   Architectures must ensure that kmalloc'ed buffer is
+   DMA-safe. Drivers and subsystems depend on it. If an architecture
+   isn't fully DMA-coherent (i.e. hardware doesn't ensure that data in
+   the CPU cache is identical to data in main memory),
+   ARCH_KMALLOC_MINALIGN must be set so that the memory allocator
+   makes sure that kmalloc'ed buffer doesn't share a cache line with
+   the others. See arch/arm/include/asm/cache.h as an example.
+
+   Note that ARCH_KMALLOC_MINALIGN is about DMA memory alignment
+   constraints. You don't need to worry about the architecture data
+   alignment constraints (e.g. the alignment constraints about 64-bit
+   objects).
 
 			   Closing
 
_

Patches currently in -mm which might be from fujita.tomonori@lab.ntt.co.jp are

origin.patch
linux-next.patch
scsi-add-__init-__exit-macros-to-ibmvstgtc.patch
ia64-remove-unnecessary-sync_single_range_-in-swiotlb_dma_ops.patch
x86-remove-unnecessary-sync_single_range_-in-swiotlb_dma_ops.patch
powerpc-remove-unnecessary-sync_single_range_-in-swiotlb_dma_ops.patch
swiotlb-remove-unnecessary-swiotlb_sync_single_range_.patch
dma-mapping-remove-unnecessary-sync_single_range_-in-dma_map_ops.patch
documentation-add-networking-drivers-mapping-error-handling-to-dma-api-howto.patch
staging-saa7134-go7007-replace-dma_sync_single-with-dma_sync_single_for_cpu.patch
dma-mapping-remove-deprecated-dma_sync_single-and-dma_sync_sg-api.patch
documentation-add-scsi-drivers-mapping-error-handling-to-dma-api-howto.patch
documentation-update-scatterlist-struct-description-in-dma-api-howto.patch
documentation-move-the-error-handling-to-the-better-place-in-dma-api-howto.patch
documentation-dma-api-howto-add-arch_kmalloc_minalign-description.patch
ssb-add-dma_dev-to-ssb_device-structure.patch
b43legacy-replace-the-ssb_dma-api-with-the-generic-dma-api.patch
b43-replace-the-ssb_dma-api-with-the-generic-dma-api.patch
b44-replace-the-ssb_dma-api-with-the-generic-dma-api.patch
ssb-remove-the-ssb-dma-api.patch
asm-generic-remove-isa_dma_threshold-in-scatterlisth.patch
asm-generic-add-need_sg_dma_length-to-define-sg_dma_len.patch
x86_32-use-asm-generic-scatterlisth.patch
powerpc-use-asm-generic-scatterlisth.patch
alpha-use-asm-generic-scatterlisth.patch
asm-generic-remove-arch_has_sg_chain-in-scatterlisth.patch
avr32-use-asm-generic-scatterlisth.patch
cris-use-asm-generic-scatterlisth.patch
h8300-use-asm-generic-scatterlisth.patch
m32r-use-use-asm-generic-scatterlisth.patch
m68k-use-asm-generic-scatterlisth.patch
mips-use-use-asm-generic-scatterlisth.patch
xtensa-use-use-asm-generic-scatterlisth.patch
blackfin-use-use-asm-generic-scatterlisth.patch
frv-use-asm-generic-scatterlisth.patch
mn10300-use-asm-generic-scatterlisth.patch
parisc-use-asm-generic-scatterlisth.patch