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, 8 insertions, 18 deletions

diff --git a/drivers/media/platform/sti/bdisp/bdisp-hw.c b/drivers/media/platform/sti/bdisp/bdisp-hw.c
index 3df66d1..b7892f3 100644
--- a/drivers/media/platform/sti/bdisp/bdisp-hw.c
+++ b/drivers/media/platform/sti/bdisp/bdisp-hw.c
@@ -430,14 +430,11 @@ int bdisp_hw_get_and_clear_irq(struct bdisp_dev *bdisp)
  */
 void bdisp_hw_free_nodes(struct bdisp_ctx *ctx)
 {
-	if (ctx && ctx->node[0]) {
-		DEFINE_DMA_ATTRS(attrs);
-
-		dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
+	if (ctx && ctx->node[0])
 		dma_free_attrs(ctx->bdisp_dev->dev,
 			       sizeof(struct bdisp_node) * MAX_NB_NODE,
-			       ctx->node[0], ctx->node_paddr[0], &attrs);
-	}
+			       ctx->node[0], ctx->node_paddr[0],
+			       DMA_ATTR_WRITE_COMBINE);
 }
 
 /**
@@ -455,12 +452,10 @@ int bdisp_hw_alloc_nodes(struct bdisp_ctx *ctx)
 	unsigned int i, node_size = sizeof(struct bdisp_node);
 	void *base;
 	dma_addr_t paddr;
-	DEFINE_DMA_ATTRS(attrs);
 
 	/* Allocate all the nodes within a single memory page */
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
 	base = dma_alloc_attrs(dev, node_size * MAX_NB_NODE, &paddr,
-			       GFP_KERNEL | GFP_DMA, &attrs);
+			       GFP_KERNEL | GFP_DMA, DMA_ATTR_WRITE_COMBINE);
 	if (!base) {
 		dev_err(dev, "%s no mem\n", __func__);
 		return -ENOMEM;
@@ -493,13 +488,9 @@ void bdisp_hw_free_filters(struct device *dev)
 {
 	int size = (BDISP_HF_NB * NB_H_FILTER) + (BDISP_VF_NB * NB_V_FILTER);
 
-	if (bdisp_h_filter[0].virt) {
-		DEFINE_DMA_ATTRS(attrs);
-
-		dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
+	if (bdisp_h_filter[0].virt)
 		dma_free_attrs(dev, size, bdisp_h_filter[0].virt,
-			       bdisp_h_filter[0].paddr, &attrs);
-	}
+			       bdisp_h_filter[0].paddr, DMA_ATTR_WRITE_COMBINE);
 }
 
 /**
@@ -516,12 +507,11 @@ int bdisp_hw_alloc_filters(struct device *dev)
 	unsigned int i, size;
 	void *base;
 	dma_addr_t paddr;
-	DEFINE_DMA_ATTRS(attrs);
 
 	/* Allocate all the filters within a single memory page */
 	size = (BDISP_HF_NB * NB_H_FILTER) + (BDISP_VF_NB * NB_V_FILTER);
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
-	base = dma_alloc_attrs(dev, size, &paddr, GFP_KERNEL | GFP_DMA, &attrs);
+	base = dma_alloc_attrs(dev, size, &paddr, GFP_KERNEL | GFP_DMA,
+			       DMA_ATTR_WRITE_COMBINE);
 	if (!base)
 		return -ENOMEM;