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>

2 files changed, 8 insertions, 11 deletions

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
index 059e902f872d..b70f9423379c 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.c
@@ -17,8 +17,6 @@
 #include <drm/drm_gem.h>
 #include <drm/drm_vma_manager.h>
 
-#include <linux/dma-attrs.h>
-
 #include "rockchip_drm_drv.h"
 #include "rockchip_drm_gem.h"
 
@@ -28,15 +26,14 @@ static int rockchip_gem_alloc_buf(struct rockchip_gem_object *rk_obj,
 	struct drm_gem_object *obj = &rk_obj->base;
 	struct drm_device *drm = obj->dev;
 
-	init_dma_attrs(&rk_obj->dma_attrs);
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &rk_obj->dma_attrs);
+	rk_obj->dma_attrs = DMA_ATTR_WRITE_COMBINE;
 
 	if (!alloc_kmap)
-		dma_set_attr(DMA_ATTR_NO_KERNEL_MAPPING, &rk_obj->dma_attrs);
+		rk_obj->dma_attrs |= DMA_ATTR_NO_KERNEL_MAPPING;
 
 	rk_obj->kvaddr = dma_alloc_attrs(drm->dev, obj->size,
 					 &rk_obj->dma_addr, GFP_KERNEL,
-					 &rk_obj->dma_attrs);
+					 rk_obj->dma_attrs);
 	if (!rk_obj->kvaddr) {
 		DRM_ERROR("failed to allocate %zu byte dma buffer", obj->size);
 		return -ENOMEM;
@@ -51,7 +48,7 @@ static void rockchip_gem_free_buf(struct rockchip_gem_object *rk_obj)
 	struct drm_device *drm = obj->dev;
 
 	dma_free_attrs(drm->dev, obj->size, rk_obj->kvaddr, rk_obj->dma_addr,
-		       &rk_obj->dma_attrs);
+		       rk_obj->dma_attrs);
 }
 
 static int rockchip_drm_gem_object_mmap(struct drm_gem_object *obj,
@@ -70,7 +67,7 @@ static int rockchip_drm_gem_object_mmap(struct drm_gem_object *obj,
 	vma->vm_pgoff = 0;
 
 	ret = dma_mmap_attrs(drm->dev, vma, rk_obj->kvaddr, rk_obj->dma_addr,
-			     obj->size, &rk_obj->dma_attrs);
+			     obj->size, rk_obj->dma_attrs);
 	if (ret)
 		drm_gem_vm_close(vma);
 
@@ -262,7 +259,7 @@ struct sg_table *rockchip_gem_prime_get_sg_table(struct drm_gem_object *obj)
 
 	ret = dma_get_sgtable_attrs(drm->dev, sgt, rk_obj->kvaddr,
 				    rk_obj->dma_addr, obj->size,
-				    &rk_obj->dma_attrs);
+				    rk_obj->dma_attrs);
 	if (ret) {
 		DRM_ERROR("failed to allocate sgt, %d\n", ret);
 		kfree(sgt);
@@ -276,7 +273,7 @@ void *rockchip_gem_prime_vmap(struct drm_gem_object *obj)
 {
 	struct rockchip_gem_object *rk_obj = to_rockchip_obj(obj);
 
-	if (dma_get_attr(DMA_ATTR_NO_KERNEL_MAPPING, &rk_obj->dma_attrs))
+	if (rk_obj->dma_attrs & DMA_ATTR_NO_KERNEL_MAPPING)
 		return NULL;
 
 	return rk_obj->kvaddr;
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_gem.h b/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
index ad22618473a4..18b3488db4ec 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_gem.h
@@ -23,7 +23,7 @@ struct rockchip_gem_object {
 
 	void *kvaddr;
 	dma_addr_t dma_addr;
-	struct dma_attrs dma_attrs;
+	unsigned long dma_attrs;
 };
 
 struct sg_table *rockchip_gem_prime_get_sg_table(struct drm_gem_object *obj);