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/video/fbdev/omap2/omapfb/omapfb-main.c

@@ -1332,7 +1332,7 @@ static void omapfb_free_fbmem(struct fb_info *fbi)
 	}
 
 	dma_free_attrs(fbdev->dev, rg->size, rg->token, rg->dma_handle,
-			&rg->attrs);
+			rg->attrs);
 
 	rg->token = NULL;
 	rg->vaddr = NULL;
@@ -1370,7 +1370,7 @@ static int omapfb_alloc_fbmem(struct fb_info *fbi, unsigned long size,
 	struct omapfb2_device *fbdev = ofbi->fbdev;
 	struct omapfb2_mem_region *rg;
 	void *token;
-	DEFINE_DMA_ATTRS(attrs);
+	unsigned long attrs;
 	dma_addr_t dma_handle;
 	int r;
 
@@ -1386,15 +1386,15 @@ static int omapfb_alloc_fbmem(struct fb_info *fbi, unsigned long size,
 
 	size = PAGE_ALIGN(size);
 
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
+	attrs = DMA_ATTR_WRITE_COMBINE;
 
 	if (ofbi->rotation_type == OMAP_DSS_ROT_VRFB)
-		dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, &attrs);
+		attrs |= DMA_ATTR_NO_KERNEL_MAPPING;
 
 	DBG("allocating %lu bytes for fb %d\n", size, ofbi->id);
 
 	token = dma_alloc_attrs(fbdev->dev, size, &dma_handle,
-			GFP_KERNEL, &attrs);
+			GFP_KERNEL, attrs);
 
 	if (token == NULL) {
 		dev_err(fbdev->dev, "failed to allocate framebuffer\n");
@@ -1408,7 +1408,7 @@ static int omapfb_alloc_fbmem(struct fb_info *fbi, unsigned long size,
 		r = omap_vrfb_request_ctx(&rg->vrfb);
 		if (r) {
 			dma_free_attrs(fbdev->dev, size, token, dma_handle,
-					&attrs);
+					attrs);
 			dev_err(fbdev->dev, "vrfb create ctx failed\n");
 			return r;
 		}

drivers/video/fbdev/omap2/omapfb/omapfb.h

@@ -28,7 +28,6 @@
 #endif
 
 #include <linux/rwsem.h>
-#include <linux/dma-attrs.h>
 #include <linux/dma-mapping.h>
 
 #include <video/omapfb_dss.h>
@@ -51,7 +50,7 @@ extern bool omapfb_debug;
 
 struct omapfb2_mem_region {
 	int             id;
-	struct dma_attrs attrs;
+	unsigned long	attrs;
 	void		*token;
 	dma_addr_t	dma_handle;
 	u32		paddr;