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/arc/mm/dma.c

@@ -22,7 +22,7 @@
 
 
 static void *arc_dma_alloc(struct device *dev, size_t size,
-		dma_addr_t *dma_handle, gfp_t gfp, struct dma_attrs *attrs)
+		dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
 {
 	unsigned long order = get_order(size);
 	struct page *page;
@@ -46,7 +46,7 @@ static void *arc_dma_alloc(struct device *dev, size_t size,
 	 *   (vs. always going to memory - thus are faster)
 	 */
 	if ((is_isa_arcv2() && ioc_exists) ||
-	    dma_get_attr(DMA_ATTR_NON_CONSISTENT, attrs))
+	    (attrs & DMA_ATTR_NON_CONSISTENT))
 		need_coh = 0;
 
 	/*
@@ -90,13 +90,13 @@ static void *arc_dma_alloc(struct device *dev, size_t size,
 }
 
 static void arc_dma_free(struct device *dev, size_t size, void *vaddr,
-		dma_addr_t dma_handle, struct dma_attrs *attrs)
+		dma_addr_t dma_handle, unsigned long attrs)
 {
 	phys_addr_t paddr = plat_dma_to_phys(dev, dma_handle);
 	struct page *page = virt_to_page(paddr);
 	int is_non_coh = 1;
 
-	is_non_coh = dma_get_attr(DMA_ATTR_NON_CONSISTENT, attrs) ||
+	is_non_coh = (attrs & DMA_ATTR_NON_CONSISTENT) ||
 			(is_isa_arcv2() && ioc_exists);
 
 	if (PageHighMem(page) || !is_non_coh)
@@ -130,7 +130,7 @@ static void _dma_cache_sync(phys_addr_t paddr, size_t size,
 
 static dma_addr_t arc_dma_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 paddr = page_to_phys(page) + offset;
 	_dma_cache_sync(paddr, size, dir);
@@ -138,7 +138,7 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
 }
 
 static int arc_dma_map_sg(struct device *dev, struct scatterlist *sg,
-	   int nents, enum dma_data_direction dir, struct dma_attrs *attrs)
+	   int nents, enum dma_data_direction dir, unsigned long attrs)
 {
 	struct scatterlist *s;
 	int i;