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, 12 insertions, 11 deletions

diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 070f1ae5cfad..7297fce9bf80 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -286,7 +286,7 @@ static inline void zpci_err_dma(unsigned long rc, unsigned long addr)
 static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
 				     unsigned long offset, size_t size,
 				     enum dma_data_direction direction,
-				     struct dma_attrs *attrs)
+				     unsigned long attrs)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long nr_pages, iommu_page_index;
@@ -332,7 +332,7 @@ out_err:
 
 static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
 				 size_t size, enum dma_data_direction direction,
-				 struct dma_attrs *attrs)
+				 unsigned long attrs)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	unsigned long iommu_page_index;
@@ -355,7 +355,7 @@ static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
 
 static void *s390_dma_alloc(struct device *dev, size_t size,
 			    dma_addr_t *dma_handle, gfp_t flag,
-			    struct dma_attrs *attrs)
+			    unsigned long attrs)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 	struct page *page;
@@ -370,7 +370,7 @@ static void *s390_dma_alloc(struct device *dev, size_t size,
 	pa = page_to_phys(page);
 	memset((void *) pa, 0, size);
 
-	map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, NULL);
+	map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
 	if (dma_mapping_error(dev, map)) {
 		free_pages(pa, get_order(size));
 		return NULL;
@@ -384,19 +384,19 @@ static void *s390_dma_alloc(struct device *dev, size_t size,
 
 static void s390_dma_free(struct device *dev, size_t size,
 			  void *pa, dma_addr_t dma_handle,
-			  struct dma_attrs *attrs)
+			  unsigned long attrs)
 {
 	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
 
 	size = PAGE_ALIGN(size);
 	atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
-	s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, NULL);
+	s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, 0);
 	free_pages((unsigned long) pa, get_order(size));
 }
 
 static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 			   int nr_elements, enum dma_data_direction dir,
-			   struct dma_attrs *attrs)
+			   unsigned long attrs)
 {
 	int mapped_elements = 0;
 	struct scatterlist *s;
@@ -405,7 +405,7 @@ static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 	for_each_sg(sg, s, nr_elements, i) {
 		struct page *page = sg_page(s);
 		s->dma_address = s390_dma_map_pages(dev, page, s->offset,
-						    s->length, dir, NULL);
+						    s->length, dir, 0);
 		if (!dma_mapping_error(dev, s->dma_address)) {
 			s->dma_length = s->length;
 			mapped_elements++;
@@ -419,7 +419,7 @@ unmap:
 	for_each_sg(sg, s, mapped_elements, i) {
 		if (s->dma_address)
 			s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
-					     dir, NULL);
+					     dir, 0);
 		s->dma_address = 0;
 		s->dma_length = 0;
 	}
@@ -429,13 +429,14 @@ unmap:
 
 static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
 			      int nr_elements, enum dma_data_direction dir,
-			      struct dma_attrs *attrs)
+			      unsigned long attrs)
 {
 	struct scatterlist *s;
 	int i;
 
 	for_each_sg(sg, s, nr_elements, i) {
-		s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir, NULL);
+		s390_dma_unmap_pages(dev, s->dma_address, s->dma_length, dir,
+				     0);
 		s->dma_address = 0;
 		s->dma_length = 0;
 	}