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]>

arch/sh/include/asm/dma-mapping.h

@@ -17,9 +17,9 @@ void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
 /* arch/sh/mm/consistent.c */
 extern void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 					dma_addr_t *dma_addr, gfp_t flag,
-					struct dma_attrs *attrs);
+					unsigned long attrs);
 extern void dma_generic_free_coherent(struct device *dev, size_t size,
 				      void *vaddr, dma_addr_t dma_handle,
-				      struct dma_attrs *attrs);
+				      unsigned long attrs);
 
 #endif /* __ASM_SH_DMA_MAPPING_H */

arch/sh/kernel/dma-nommu.c

@@ -13,7 +13,7 @@
 static dma_addr_t nommu_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)
 {
 	dma_addr_t addr = page_to_phys(page) + offset;
 
@@ -25,7 +25,7 @@ static dma_addr_t nommu_map_page(struct device *dev, struct page *page,
 
 static int nommu_map_sg(struct device *dev, struct scatterlist *sg,
 			int nents, enum dma_data_direction dir,
-			struct dma_attrs *attrs)
+			unsigned long attrs)
 {
 	struct scatterlist *s;
 	int i;

arch/sh/mm/consistent.c

@@ -34,7 +34,7 @@ fs_initcall(dma_init);
 
 void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 				 dma_addr_t *dma_handle, gfp_t gfp,
-				 struct dma_attrs *attrs)
+				 unsigned long attrs)
 {
 	void *ret, *ret_nocache;
 	int order = get_order(size);
@@ -66,7 +66,7 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 
 void dma_generic_free_coherent(struct device *dev, size_t size,
 			       void *vaddr, dma_addr_t dma_handle,
-			       struct dma_attrs *attrs)
+			       unsigned long attrs)
 {
 	int order = get_order(size);
 	unsigned long pfn = dma_handle >> PAGE_SHIFT;