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, 6 insertions, 7 deletions

diff --git a/arch/arm/include/asm/dma-mapping.h b/arch/arm/include/asm/dma-mapping.h
index a83570f10124..d009f7911ffc 100644
--- a/arch/arm/include/asm/dma-mapping.h
+++ b/arch/arm/include/asm/dma-mapping.h
@@ -5,7 +5,6 @@
 
 #include <linux/mm_types.h>
 #include <linux/scatterlist.h>
-#include <linux/dma-attrs.h>
 #include <linux/dma-debug.h>
 
 #include <asm/memory.h>
@@ -174,7 +173,7 @@ static inline void dma_mark_clean(void *addr, size_t size) { }
  * to be the device-viewed address.
  */
 extern void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
-			   gfp_t gfp, struct dma_attrs *attrs);
+			   gfp_t gfp, unsigned long attrs);
 
 /**
  * arm_dma_free - free memory allocated by arm_dma_alloc
@@ -191,7 +190,7 @@ extern void *arm_dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
  * during and after this call executing are illegal.
  */
 extern void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
-			 dma_addr_t handle, struct dma_attrs *attrs);
+			 dma_addr_t handle, unsigned long attrs);
 
 /**
  * arm_dma_mmap - map a coherent DMA allocation into user space
@@ -208,7 +207,7 @@ extern void arm_dma_free(struct device *dev, size_t size, void *cpu_addr,
  */
 extern int arm_dma_mmap(struct device *dev, struct vm_area_struct *vma,
 			void *cpu_addr, dma_addr_t dma_addr, size_t size,
-			struct dma_attrs *attrs);
+			unsigned long attrs);
 
 /*
  * This can be called during early boot to increase the size of the atomic
@@ -262,16 +261,16 @@ extern void dmabounce_unregister_dev(struct device *);
  * The scatter list versions of the above methods.
  */
 extern int arm_dma_map_sg(struct device *, struct scatterlist *, int,
-		enum dma_data_direction, struct dma_attrs *attrs);
+		enum dma_data_direction, unsigned long attrs);
 extern void arm_dma_unmap_sg(struct device *, struct scatterlist *, int,
-		enum dma_data_direction, struct dma_attrs *attrs);
+		enum dma_data_direction, unsigned long attrs);
 extern void arm_dma_sync_sg_for_cpu(struct device *, struct scatterlist *, int,
 		enum dma_data_direction);
 extern void arm_dma_sync_sg_for_device(struct device *, struct scatterlist *, int,
 		enum dma_data_direction);
 extern int arm_dma_get_sgtable(struct device *dev, struct sg_table *sgt,
 		void *cpu_addr, dma_addr_t dma_addr, size_t size,
-		struct dma_attrs *attrs);
+		unsigned long attrs);
 
 #endif /* __KERNEL__ */
 #endif