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/1468399300-5399-2-git-send-email-k.kozlowski@samsung.com
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no>
Acked-by: Mark Salter <msalter@redhat.com> [c6x]
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> [cris]
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> [drm]
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Fabien Dessenne <fabien.dessenne@st.com> [bdisp]
Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> [vb2-core]
Acked-by: David Vrabel <david.vrabel@citrix.com> [xen]
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [xen swiotlb]
Acked-by: Joerg Roedel <jroedel@suse.de> [iommu]
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon]
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> [s390]
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> [avr32]
Acked-by: Vineet Gupta <vgupta@synopsys.com> [arc]
Acked-by: Robin Murphy <robin.murphy@arm.com> [arm64 and dma-iommu]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/powerpc/kernel/iommu.c

@@ -307,7 +307,7 @@ static dma_addr_t iommu_alloc(struct device *dev, struct iommu_table *tbl,
 			      void *page, unsigned int npages,
 			      enum dma_data_direction direction,
 			      unsigned long mask, unsigned int align_order,
-			      struct dma_attrs *attrs)
+			      unsigned long attrs)
 {
 	unsigned long entry;
 	dma_addr_t ret = DMA_ERROR_CODE;
@@ -431,7 +431,7 @@ static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
 int ppc_iommu_map_sg(struct device *dev, struct iommu_table *tbl,
 		     struct scatterlist *sglist, int nelems,
 		     unsigned long mask, enum dma_data_direction direction,
-		     struct dma_attrs *attrs)
+		     unsigned long attrs)
 {
 	dma_addr_t dma_next = 0, dma_addr;
 	struct scatterlist *s, *outs, *segstart;
@@ -574,7 +574,7 @@ int ppc_iommu_map_sg(struct device *dev, struct iommu_table *tbl,
 
 void ppc_iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 			int nelems, enum dma_data_direction direction,
-			struct dma_attrs *attrs)
+			unsigned long attrs)
 {
 	struct scatterlist *sg;
 
@@ -753,7 +753,7 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name)
 dma_addr_t iommu_map_page(struct device *dev, struct iommu_table *tbl,
 			  struct page *page, unsigned long offset, size_t size,
 			  unsigned long mask, enum dma_data_direction direction,
-			  struct dma_attrs *attrs)
+			  unsigned long attrs)
 {
 	dma_addr_t dma_handle = DMA_ERROR_CODE;
 	void *vaddr;
@@ -790,7 +790,7 @@ dma_addr_t iommu_map_page(struct device *dev, struct iommu_table *tbl,
 
 void iommu_unmap_page(struct iommu_table *tbl, dma_addr_t dma_handle,
 		      size_t size, enum dma_data_direction direction,
-		      struct dma_attrs *attrs)
+		      unsigned long attrs)
 {
 	unsigned int npages;
 
@@ -845,7 +845,7 @@ void *iommu_alloc_coherent(struct device *dev, struct iommu_table *tbl,
 	nio_pages = size >> tbl->it_page_shift;
 	io_order = get_iommu_order(size, tbl);
 	mapping = iommu_alloc(dev, tbl, ret, nio_pages, DMA_BIDIRECTIONAL,
-			      mask >> tbl->it_page_shift, io_order, NULL);
+			      mask >> tbl->it_page_shift, io_order, 0);
 	if (mapping == DMA_ERROR_CODE) {
 		free_pages((unsigned long)ret, order);
 		return NULL;