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>

1 files changed, 10 insertions, 10 deletions

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index 42d27a62a404..63ff468a7986 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -241,7 +241,7 @@ static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
 static dma_addr_t gart_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)
 {
 	unsigned long bus;
 	phys_addr_t paddr = page_to_phys(page) + offset;
@@ -263,7 +263,7 @@ static dma_addr_t gart_map_page(struct device *dev, struct page *page,
  */
 static void gart_unmap_page(struct device *dev, dma_addr_t dma_addr,
 			    size_t size, enum dma_data_direction dir,
-			    struct dma_attrs *attrs)
+			    unsigned long attrs)
 {
 	unsigned long iommu_page;
 	int npages;
@@ -285,7 +285,7 @@ static void gart_unmap_page(struct device *dev, dma_addr_t dma_addr,
  * Wrapper for pci_unmap_single working with scatterlists.
  */
 static void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
-			  enum dma_data_direction dir, struct dma_attrs *attrs)
+			  enum dma_data_direction dir, unsigned long attrs)
 {
 	struct scatterlist *s;
 	int i;
@@ -293,7 +293,7 @@ static void gart_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,
 	for_each_sg(sg, s, nents, i) {
 		if (!s->dma_length || !s->length)
 			break;
-		gart_unmap_page(dev, s->dma_address, s->dma_length, dir, NULL);
+		gart_unmap_page(dev, s->dma_address, s->dma_length, dir, 0);
 	}
 }
 
@@ -315,7 +315,7 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
 			addr = dma_map_area(dev, addr, s->length, dir, 0);
 			if (addr == bad_dma_addr) {
 				if (i > 0)
-					gart_unmap_sg(dev, sg, i, dir, NULL);
+					gart_unmap_sg(dev, sg, i, dir, 0);
 				nents = 0;
 				sg[0].dma_length = 0;
 				break;
@@ -386,7 +386,7 @@ dma_map_cont(struct device *dev, struct scatterlist *start, int nelems,
  * Merge chunks that have page aligned sizes into a continuous mapping.
  */
 static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,
-		       enum dma_data_direction dir, struct dma_attrs *attrs)
+		       enum dma_data_direction dir, unsigned long attrs)
 {
 	struct scatterlist *s, *ps, *start_sg, *sgmap;
 	int need = 0, nextneed, i, out, start;
@@ -456,7 +456,7 @@ static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 
 error:
 	flush_gart();
-	gart_unmap_sg(dev, sg, out, dir, NULL);
+	gart_unmap_sg(dev, sg, out, dir, 0);
 
 	/* When it was forced or merged try again in a dumb way */
 	if (force_iommu || iommu_merge) {
@@ -476,7 +476,7 @@ error:
 /* allocate and map a coherent mapping */
 static void *
 gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
-		    gfp_t flag, struct dma_attrs *attrs)
+		    gfp_t flag, unsigned long attrs)
 {
 	dma_addr_t paddr;
 	unsigned long align_mask;
@@ -508,9 +508,9 @@ gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
 /* free a coherent mapping */
 static void
 gart_free_coherent(struct device *dev, size_t size, void *vaddr,
-		   dma_addr_t dma_addr, struct dma_attrs *attrs)
+		   dma_addr_t dma_addr, unsigned long attrs)
 {
-	gart_unmap_page(dev, dma_addr, size, DMA_BIDIRECTIONAL, NULL);
+	gart_unmap_page(dev, dma_addr, size, DMA_BIDIRECTIONAL, 0);
 	dma_generic_free_coherent(dev, size, vaddr, dma_addr, attrs);
 }