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, 11 deletions

diff --git a/arch/openrisc/kernel/dma.c b/arch/openrisc/kernel/dma.c
index 0b77ddb1ee07..140c99140649 100644
--- a/arch/openrisc/kernel/dma.c
+++ b/arch/openrisc/kernel/dma.c
@@ -22,7 +22,6 @@
 #include <linux/dma-mapping.h>
 #include <linux/dma-debug.h>
 #include <linux/export.h>
-#include <linux/dma-attrs.h>
 
 #include <asm/cpuinfo.h>
 #include <asm/spr_defs.h>
@@ -83,7 +82,7 @@ page_clear_nocache(pte_t *pte, unsigned long addr,
 static void *
 or1k_dma_alloc(struct device *dev, size_t size,
 	       dma_addr_t *dma_handle, gfp_t gfp,
-	       struct dma_attrs *attrs)
+	       unsigned long attrs)
 {
 	unsigned long va;
 	void *page;
@@ -101,7 +100,7 @@ or1k_dma_alloc(struct device *dev, size_t size,
 
 	va = (unsigned long)page;
 
-	if (!dma_get_attr(DMA_ATTR_NON_CONSISTENT, attrs)) {
+	if ((attrs & DMA_ATTR_NON_CONSISTENT) == 0) {
 		/*
 		 * We need to iterate through the pages, clearing the dcache for
 		 * them and setting the cache-inhibit bit.
@@ -117,7 +116,7 @@ or1k_dma_alloc(struct device *dev, size_t size,
 
 static void
 or1k_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)
 {
 	unsigned long va = (unsigned long)vaddr;
 	struct mm_walk walk = {
@@ -125,7 +124,7 @@ or1k_dma_free(struct device *dev, size_t size, void *vaddr,
 		.mm = &init_mm
 	};
 
-	if (!dma_get_attr(DMA_ATTR_NON_CONSISTENT, attrs)) {
+	if ((attrs & DMA_ATTR_NON_CONSISTENT) == 0) {
 		/* walk_page_range shouldn't be able to fail here */
 		WARN_ON(walk_page_range(va, va + size, &walk));
 	}
@@ -137,7 +136,7 @@ static dma_addr_t
 or1k_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 cl;
 	dma_addr_t addr = page_to_phys(page) + offset;
@@ -170,7 +169,7 @@ or1k_map_page(struct device *dev, struct page *page,
 static void
 or1k_unmap_page(struct device *dev, dma_addr_t dma_handle,
 		size_t size, enum dma_data_direction dir,
-		struct dma_attrs *attrs)
+		unsigned long attrs)
 {
 	/* Nothing special to do here... */
 }
@@ -178,14 +177,14 @@ or1k_unmap_page(struct device *dev, dma_addr_t dma_handle,
 static int
 or1k_map_sg(struct device *dev, struct scatterlist *sg,
 	    int nents, enum dma_data_direction dir,
-	    struct dma_attrs *attrs)
+	    unsigned long attrs)
 {
 	struct scatterlist *s;
 	int i;
 
 	for_each_sg(sg, s, nents, i) {
 		s->dma_address = or1k_map_page(dev, sg_page(s), s->offset,
-					       s->length, dir, NULL);
+					       s->length, dir, 0);
 	}
 
 	return nents;
@@ -194,13 +193,13 @@ or1k_map_sg(struct device *dev, struct scatterlist *sg,
 static void
 or1k_unmap_sg(struct device *dev, struct scatterlist *sg,
 	      int nents, enum dma_data_direction dir,
-	      struct dma_attrs *attrs)
+	      unsigned long attrs)
 {
 	struct scatterlist *s;
 	int i;
 
 	for_each_sg(sg, s, nents, i) {
-		or1k_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir, NULL);
+		or1k_unmap_page(dev, sg_dma_address(s), sg_dma_len(s), dir, 0);
 	}
 }