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>

3 files changed, 17 insertions, 34 deletions

diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 863f658..b09b2c9 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -27,7 +27,7 @@ struct vb2_dc_buf {
 	unsigned long			size;
 	void				*cookie;
 	dma_addr_t			dma_addr;
-	struct dma_attrs		attrs;
+	unsigned long			attrs;
 	enum dma_data_direction		dma_dir;
 	struct sg_table			*dma_sgt;
 	struct frame_vector		*vec;
@@ -130,12 +130,12 @@ static void vb2_dc_put(void *buf_priv)
 		kfree(buf->sgt_base);
 	}
 	dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr,
-			&buf->attrs);
+		       buf->attrs);
 	put_device(buf->dev);
 	kfree(buf);
 }
 
-static void *vb2_dc_alloc(struct device *dev, const struct dma_attrs *attrs,
+static void *vb2_dc_alloc(struct device *dev, unsigned long attrs,
 			  unsigned long size, enum dma_data_direction dma_dir,
 			  gfp_t gfp_flags)
 {
@@ -146,16 +146,16 @@ static void *vb2_dc_alloc(struct device *dev, const struct dma_attrs *attrs,
 		return ERR_PTR(-ENOMEM);
 
 	if (attrs)
-		buf->attrs = *attrs;
+		buf->attrs = attrs;
 	buf->cookie = dma_alloc_attrs(dev, size, &buf->dma_addr,
-					GFP_KERNEL | gfp_flags, &buf->attrs);
+					GFP_KERNEL | gfp_flags, buf->attrs);
 	if (!buf->cookie) {
 		dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
 		kfree(buf);
 		return ERR_PTR(-ENOMEM);
 	}
 
-	if (!dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, &buf->attrs))
+	if ((buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) == 0)
 		buf->vaddr = buf->cookie;
 
 	/* Prevent the device from being released while the buffer is used */
@@ -189,7 +189,7 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma)
 	vma->vm_pgoff = 0;
 
 	ret = dma_mmap_attrs(buf->dev, vma, buf->cookie,
-		buf->dma_addr, buf->size, &buf->attrs);
+		buf->dma_addr, buf->size, buf->attrs);
 
 	if (ret) {
 		pr_err("Remapping memory failed, error: %d\n", ret);
@@ -372,7 +372,7 @@ static struct sg_table *vb2_dc_get_base_sgt(struct vb2_dc_buf *buf)
 	}
 
 	ret = dma_get_sgtable_attrs(buf->dev, sgt, buf->cookie, buf->dma_addr,
-		buf->size, &buf->attrs);
+		buf->size, buf->attrs);
 	if (ret < 0) {
 		dev_err(buf->dev, "failed to get scatterlist from DMA API\n");
 		kfree(sgt);
@@ -421,15 +421,12 @@ static void vb2_dc_put_userptr(void *buf_priv)
 	struct page **pages;
 
 	if (sgt) {
-		DEFINE_DMA_ATTRS(attrs);
-
-		dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 		/*
 		 * No need to sync to CPU, it's already synced to the CPU
 		 * since the finish() memop will have been called before this.
 		 */
 		dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-				   buf->dma_dir, &attrs);
+				   buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 		pages = frame_vector_pages(buf->vec);
 		/* sgt should exist only if vector contains pages... */
 		BUG_ON(IS_ERR(pages));
@@ -484,9 +481,6 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
 	struct sg_table *sgt;
 	unsigned long contig_size;
 	unsigned long dma_align = dma_get_cache_alignment();
-	DEFINE_DMA_ATTRS(attrs);
-
-	dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 
 	/* Only cache aligned DMA transfers are reliable */
 	if (!IS_ALIGNED(vaddr | size, dma_align)) {
@@ -548,7 +542,7 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr,
 	 * prepare() memop is called.
 	 */
 	sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-				      buf->dma_dir, &attrs);
+				      buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 	if (sgt->nents <= 0) {
 		pr_err("failed to map scatterlist\n");
 		ret = -EIO;
@@ -572,7 +566,7 @@ out:
 
 fail_map_sg:
 	dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-			   buf->dma_dir, &attrs);
+			   buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 
 fail_sgt_init:
 	sg_free_table(sgt);
diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
index a39db8a..bd82d70 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
@@ -95,7 +95,7 @@ static int vb2_dma_sg_alloc_compacted(struct vb2_dma_sg_buf *buf,
 	return 0;
 }
 
-static void *vb2_dma_sg_alloc(struct device *dev, const struct dma_attrs *dma_attrs,
+static void *vb2_dma_sg_alloc(struct device *dev, unsigned long dma_attrs,
 			      unsigned long size, enum dma_data_direction dma_dir,
 			      gfp_t gfp_flags)
 {
@@ -103,9 +103,6 @@ static void *vb2_dma_sg_alloc(struct device *dev, const struct dma_attrs *dma_at
 	struct sg_table *sgt;
 	int ret;
 	int num_pages;
-	DEFINE_DMA_ATTRS(attrs);
-
-	dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 
 	if (WARN_ON(dev == NULL))
 		return NULL;
@@ -144,7 +141,7 @@ static void *vb2_dma_sg_alloc(struct device *dev, const struct dma_attrs *dma_at
 	 * prepare() memop is called.
 	 */
 	sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-				      buf->dma_dir, &attrs);
+				      buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 	if (!sgt->nents)
 		goto fail_map;
 
@@ -179,13 +176,10 @@ static void vb2_dma_sg_put(void *buf_priv)
 	int i = buf->num_pages;
 
 	if (atomic_dec_and_test(&buf->refcount)) {
-		DEFINE_DMA_ATTRS(attrs);
-
-		dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 		dprintk(1, "%s: Freeing buffer of %d pages\n", __func__,
 			buf->num_pages);
 		dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-				   buf->dma_dir, &attrs);
+				   buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 		if (buf->vaddr)
 			vm_unmap_ram(buf->vaddr, buf->num_pages);
 		sg_free_table(buf->dma_sgt);
@@ -228,10 +222,8 @@ static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
 {
 	struct vb2_dma_sg_buf *buf;
 	struct sg_table *sgt;
-	DEFINE_DMA_ATTRS(attrs);
 	struct frame_vector *vec;
 
-	dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 	buf = kzalloc(sizeof *buf, GFP_KERNEL);
 	if (!buf)
 		return NULL;
@@ -262,7 +254,7 @@ static void *vb2_dma_sg_get_userptr(struct device *dev, unsigned long vaddr,
 	 * prepare() memop is called.
 	 */
 	sgt->nents = dma_map_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents,
-				      buf->dma_dir, &attrs);
+				      buf->dma_dir, DMA_ATTR_SKIP_CPU_SYNC);
 	if (!sgt->nents)
 		goto userptr_fail_map;
 
@@ -286,14 +278,11 @@ static void vb2_dma_sg_put_userptr(void *buf_priv)
 	struct vb2_dma_sg_buf *buf = buf_priv;
 	struct sg_table *sgt = &buf->sg_table;
 	int i = buf->num_pages;
-	DEFINE_DMA_ATTRS(attrs);
-
-	dma_set_attr(DMA_ATTR_SKIP_CPU_SYNC, &attrs);
 
 	dprintk(1, "%s: Releasing userspace buffer of %d pages\n",
 	       __func__, buf->num_pages);
 	dma_unmap_sg_attrs(buf->dev, sgt->sgl, sgt->orig_nents, buf->dma_dir,
-			   &attrs);
+			   DMA_ATTR_SKIP_CPU_SYNC);
 	if (buf->vaddr)
 		vm_unmap_ram(buf->vaddr, buf->num_pages);
 	sg_free_table(buf->dma_sgt);
diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c
index 7e8a07e..c2820a6 100644
--- a/drivers/media/v4l2-core/videobuf2-vmalloc.c
+++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c
@@ -33,7 +33,7 @@ struct vb2_vmalloc_buf {
 
 static void vb2_vmalloc_put(void *buf_priv);
 
-static void *vb2_vmalloc_alloc(struct device *dev, const struct dma_attrs *attrs,
+static void *vb2_vmalloc_alloc(struct device *dev, unsigned long attrs,
 			       unsigned long size, enum dma_data_direction dma_dir,
 			       gfp_t gfp_flags)
 {