dma-mapping: use unsigned long for dma_attrs

The dma-mapping core and the implementations do not change the DMA
attributes passed by pointer.  Thus the pointer can point to const data.
However the attributes do not have to be a bitfield.  Instead unsigned
long will do fine:

1. This is just simpler.  Both in terms of reading the code and setting
   attributes.  Instead of initializing local attributes on the stack
   and passing pointer to it to dma_set_attr(), just set the bits.

2. It brings safeness and checking for const correctness because the
   attributes are passed by value.

Semantic patches for this change (at least most of them):

    virtual patch
    virtual context

    @r@
    identifier f, attrs;

    @@
    f(...,
    - struct dma_attrs *attrs
    + unsigned long attrs
    , ...)
    {
    ...
    }

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

and

    // Options: --all-includes
    virtual patch
    virtual context

    @r@
    identifier f, attrs;
    type t;

    @@
    t f(..., struct dma_attrs *attrs);

    @@
    identifier r.f;
    @@
    f(...,
    - NULL
    + 0
     )

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Krzysztof Kozlowski <[email protected]>
Acked-by: Vineet Gupta <[email protected]>
Acked-by: Robin Murphy <[email protected]>
Acked-by: Hans-Christian Noren Egtvedt <[email protected]>
Acked-by: Mark Salter <[email protected]> [c6x]
Acked-by: Jesper Nilsson <[email protected]> [cris]
Acked-by: Daniel Vetter <[email protected]> [drm]
Reviewed-by: Bart Van Assche <[email protected]>
Acked-by: Joerg Roedel <[email protected]> [iommu]
Acked-by: Fabien Dessenne <[email protected]> [bdisp]
Reviewed-by: Marek Szyprowski <[email protected]> [vb2-core]
Acked-by: David Vrabel <[email protected]> [xen]
Acked-by: Konrad Rzeszutek Wilk <[email protected]> [xen swiotlb]
Acked-by: Joerg Roedel <[email protected]> [iommu]
Acked-by: Richard Kuo <[email protected]> [hexagon]
Acked-by: Geert Uytterhoeven <[email protected]> [m68k]
Acked-by: Gerald Schaefer <[email protected]> [s390]
Acked-by: Bjorn Andersson <[email protected]>
Acked-by: Hans-Christian Noren Egtvedt <[email protected]> [avr32]
Acked-by: Vineet Gupta <[email protected]> [arc]
Acked-by: Robin Murphy <[email protected]> [arm64 and dma-iommu]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
index 8443bbb..81c5c8d1 100644
--- a/include/linux/dma-iommu.h
+++ b/include/linux/dma-iommu.h
@@ -39,7 +39,7 @@
  * the arch code to take care of attributes and cache maintenance
  */
 struct page **iommu_dma_alloc(struct device *dev, size_t size, gfp_t gfp,
-		struct dma_attrs *attrs, int prot, dma_addr_t *handle,
+		unsigned long attrs, int prot, dma_addr_t *handle,
 		void (*flush_page)(struct device *, const void *, phys_addr_t));
 void iommu_dma_free(struct device *dev, struct page **pages, size_t size,
 		dma_addr_t *handle);
@@ -56,9 +56,9 @@
  * directly as DMA mapping callbacks for simplicity
  */
 void iommu_dma_unmap_page(struct device *dev, dma_addr_t handle, size_t size,
-		enum dma_data_direction dir, struct dma_attrs *attrs);
+		enum dma_data_direction dir, unsigned long attrs);
 void iommu_dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
-		enum dma_data_direction dir, struct dma_attrs *attrs);
+		enum dma_data_direction dir, unsigned long attrs);
 int iommu_dma_supported(struct device *dev, u64 mask);
 int iommu_dma_mapping_error(struct device *dev, dma_addr_t dma_addr);