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]>

drivers/xen/swiotlb-xen.c

@@ -294,7 +294,7 @@ error:
 void *
 xen_swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 			   dma_addr_t *dma_handle, gfp_t flags,
-			   struct dma_attrs *attrs)
+			   unsigned long attrs)
 {
 	void *ret;
 	int order = get_order(size);
@@ -346,7 +346,7 @@ EXPORT_SYMBOL_GPL(xen_swiotlb_alloc_coherent);
 
 void
 xen_swiotlb_free_coherent(struct device *hwdev, size_t size, void *vaddr,
-			  dma_addr_t dev_addr, struct dma_attrs *attrs)
+			  dma_addr_t dev_addr, unsigned long attrs)
 {
 	int order = get_order(size);
 	phys_addr_t phys;
@@ -378,7 +378,7 @@ EXPORT_SYMBOL_GPL(xen_swiotlb_free_coherent);
 dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 				unsigned long offset, size_t size,
 				enum dma_data_direction dir,
-				struct dma_attrs *attrs)
+				unsigned long attrs)
 {
 	phys_addr_t map, phys = page_to_phys(page) + offset;
 	dma_addr_t dev_addr = xen_phys_to_bus(phys);
@@ -434,7 +434,7 @@ EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
  */
 static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
 			     size_t size, enum dma_data_direction dir,
-				 struct dma_attrs *attrs)
+			     unsigned long attrs)
 {
 	phys_addr_t paddr = xen_bus_to_phys(dev_addr);
 
@@ -462,7 +462,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
 
 void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
 			    size_t size, enum dma_data_direction dir,
-			    struct dma_attrs *attrs)
+			    unsigned long attrs)
 {
 	xen_unmap_single(hwdev, dev_addr, size, dir, attrs);
 }
@@ -538,7 +538,7 @@ EXPORT_SYMBOL_GPL(xen_swiotlb_sync_single_for_device);
 int
 xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 			 int nelems, enum dma_data_direction dir,
-			 struct dma_attrs *attrs)
+			 unsigned long attrs)
 {
 	struct scatterlist *sg;
 	int i;
@@ -599,7 +599,7 @@ EXPORT_SYMBOL_GPL(xen_swiotlb_map_sg_attrs);
 void
 xen_swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 			   int nelems, enum dma_data_direction dir,
-			   struct dma_attrs *attrs)
+			   unsigned long attrs)
 {
 	struct scatterlist *sg;
 	int i;