dma: add dma_*map*_attrs() interfaces

v5-v6 changes:

- if CONFIG_HAVE_DMA_ATTRS isn't defined , use macros to define dma_*map*_attrs() - this gets around a build problem on alpha, and maybe other arches, too.

- fix ib_umem_get() call in drivers/infiniband/hw/nes/nes_verbs.c

---

Introduce new interfaces, dma_*map*_attrs(), for passing architecture-specific attributes when memory is mapped and unmapped for DMA. Give the interfaces default implementations which ignore attributes. Also introduce the dma_{set|get}_attr() interfaces for setting and retrieving individual attributes. Define one attribute, DMA_ATTR_WRITE_BARRIER, in anticipation of its use by ia64/sn. Select whether architectures implement arch-specific versions of the dma_*map*_attrs() interfaces via HAVE_DMA_ATTRS in Kconfig.

---

 arch/Kconfig                |    3 +
 arch/ia64/Kconfig           |    1 
 include/linux/dma-attrs.h   |   74 ++++++++++++++++++++++++++++++++++++++++++++
 include/linux/dma-mapping.h |   17 ++++++++++
 4 files changed, 95 insertions(+)

index 694c9af..3ea332b 100644
@@ -36,3 +36,6 @@ config HAVE_KPROBES
 
 config HAVE_KRETPROBES
 	def_bool n
+
+config HAVE_DMA_ATTRS
+	def_bool n

index 8fa3faf..985b267 100644
@@ -19,6 +19,7 @@ config IA64
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
+	select HAVE_DMA_ATTRS
 	default y
 	help
 	  The Itanium Processor Family is Intel's 64-bit successor to

index 3320307..952e0f8 100644
@@ -146,4 +146,21 @@ static inline void dmam_release_declared_memory(struct device *dev)
 }
 #endif /* ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY */
 
+#ifndef CONFIG_HAVE_DMA_ATTRS
+struct dma_attrs;
+
+#define dma_map_single_attrs(dev, cpu_addr, size, dir, attrs) \
+	dma_map_single(dev, cpu_addr, size, dir)
+
+#define dma_unmap_single_attrs(dev, dma_addr, size, dir, attrs) \
+	dma_unmap_single(dev, dma_addr, size, dir)
+
+#define dma_map_sg_attrs(dev, sgl, nents, dir, attrs) \
+	dma_map_sg(dev, sgl, nents, dir)
+
+#define dma_unmap_sg_attrs(dev, sgl, nents, dir, attrs) \
+	dma_unmap_sg(dev, sgl, nents, dir)
+
+#endif /* CONFIG_HAVE_DMA_ATTRS */
+
 #endif