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From: David Woodhouse on 19 May 2010 09:50
Commit 3843384a055496dfed3c93ae883d964d8290fdab ("Input: ad7877 - keep
dma rx buffers in seperate cache lines")[sic] introduced the use of
____cacheline_aligned to ensure that buffers used for DMA as part of a
structure were suitably separated from the rest of the structure.
However, aligning to the cache line size isn't necessary on
cache-coherent architectures. To avoid wasting space, the correct value
to use for the alignment is ARCH_KMALLOC_MINALIGN.
This patch provides a __dma_aligned macro which does the right thing.
Signed-off-by: David Woodhouse <David.Woodhouse(a)intel.com>
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index ca32ed7..4487cf3 100644
@@ -5,6 +5,9 @@
+#define __dma_aligned __attribute__((__aligned__(ARCH_KMALLOC_MINALIGN)))
/* These definitions mirror those in pci.h, so they can be used
* interchangeably with their PCI_ counterparts */
David Woodhouse Open Source Technology Centre
David.Woodhouse(a)intel.com Intel Corporation
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