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]>

lib/swiotlb.c

@@ -738,7 +738,7 @@ swiotlb_full(struct device *dev, size_t size, enum dma_data_direction dir,
 dma_addr_t 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 = phys_to_dma(dev, phys);
@@ -807,7 +807,7 @@ static void unmap_single(struct device *hwdev, dma_addr_t dev_addr,
 
 void 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)
 {
 	unmap_single(hwdev, dev_addr, size, dir);
 }
@@ -877,7 +877,7 @@ EXPORT_SYMBOL(swiotlb_sync_single_for_device);
  */
 int
 swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
-		     enum dma_data_direction dir, struct dma_attrs *attrs)
+		     enum dma_data_direction dir, unsigned long attrs)
 {
 	struct scatterlist *sg;
 	int i;
@@ -914,7 +914,7 @@ int
 swiotlb_map_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
 	       enum dma_data_direction dir)
 {
-	return swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, NULL);
+	return swiotlb_map_sg_attrs(hwdev, sgl, nelems, dir, 0);
 }
 EXPORT_SYMBOL(swiotlb_map_sg);
 
@@ -924,7 +924,8 @@ EXPORT_SYMBOL(swiotlb_map_sg);
  */
 void
 swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
-		       int nelems, enum dma_data_direction dir, struct dma_attrs *attrs)
+		       int nelems, enum dma_data_direction dir,
+		       unsigned long attrs)
 {
 	struct scatterlist *sg;
 	int i;
@@ -941,7 +942,7 @@ void
 swiotlb_unmap_sg(struct device *hwdev, struct scatterlist *sgl, int nelems,
 		 enum dma_data_direction dir)
 {
-	return swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, NULL);
+	return swiotlb_unmap_sg_attrs(hwdev, sgl, nelems, dir, 0);
 }
 EXPORT_SYMBOL(swiotlb_unmap_sg);