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, 84 insertions, 44 deletions

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index 71c1b215ef66..66533e18276c 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -5,13 +5,58 @@
 #include <linux/string.h>
 #include <linux/device.h>
 #include <linux/err.h>
-#include <linux/dma-attrs.h>
 #include <linux/dma-debug.h>
 #include <linux/dma-direction.h>
 #include <linux/scatterlist.h>
 #include <linux/kmemcheck.h>
 #include <linux/bug.h>
 
+/**
+ * List of possible attributes associated with a DMA mapping. The semantics
+ * of each attribute should be defined in Documentation/DMA-attributes.txt.
+ *
+ * DMA_ATTR_WRITE_BARRIER: DMA to a memory region with this attribute
+ * forces all pending DMA writes to complete.
+ */
+#define DMA_ATTR_WRITE_BARRIER		(1UL << 0)
+/*
+ * DMA_ATTR_WEAK_ORDERING: Specifies that reads and writes to the mapping
+ * may be weakly ordered, that is that reads and writes may pass each other.
+ */
+#define DMA_ATTR_WEAK_ORDERING		(1UL << 1)
+/*
+ * DMA_ATTR_WRITE_COMBINE: Specifies that writes to the mapping may be
+ * buffered to improve performance.
+ */
+#define DMA_ATTR_WRITE_COMBINE		(1UL << 2)
+/*
+ * DMA_ATTR_NON_CONSISTENT: Lets the platform to choose to return either
+ * consistent or non-consistent memory as it sees fit.
+ */
+#define DMA_ATTR_NON_CONSISTENT		(1UL << 3)
+/*
+ * DMA_ATTR_NO_KERNEL_MAPPING: Lets the platform to avoid creating a kernel
+ * virtual mapping for the allocated buffer.
+ */
+#define DMA_ATTR_NO_KERNEL_MAPPING	(1UL << 4)
+/*
+ * DMA_ATTR_SKIP_CPU_SYNC: Allows platform code to skip synchronization of
+ * the CPU cache for the given buffer assuming that it has been already
+ * transferred to 'device' domain.
+ */
+#define DMA_ATTR_SKIP_CPU_SYNC		(1UL << 5)
+/*
+ * DMA_ATTR_FORCE_CONTIGUOUS: Forces contiguous allocation of the buffer
+ * in physical memory.
+ */
+#define DMA_ATTR_FORCE_CONTIGUOUS	(1UL << 6)
+/*
+ * DMA_ATTR_ALLOC_SINGLE_PAGES: This is a hint to the DMA-mapping subsystem
+ * that it's probably not worth the time to try to allocate memory to in a way
+ * that gives better TLB efficiency.
+ */
+#define DMA_ATTR_ALLOC_SINGLE_PAGES	(1UL << 7)
+
 /*
  * A dma_addr_t can hold any valid DMA or bus address for the platform.
  * It can be given to a device to use as a DMA source or target.  A CPU cannot
@@ -21,34 +66,35 @@
 struct dma_map_ops {
 	void* (*alloc)(struct device *dev, size_t size,
 				dma_addr_t *dma_handle, gfp_t gfp,
-				struct dma_attrs *attrs);
+				unsigned long attrs);
 	void (*free)(struct device *dev, size_t size,
 			      void *vaddr, dma_addr_t dma_handle,
-			      struct dma_attrs *attrs);
+			      unsigned long attrs);
 	int (*mmap)(struct device *, struct vm_area_struct *,
-			  void *, dma_addr_t, size_t, struct dma_attrs *attrs);
+			  void *, dma_addr_t, size_t,
+			  unsigned long attrs);
 
 	int (*get_sgtable)(struct device *dev, struct sg_table *sgt, void *,
-			   dma_addr_t, size_t, struct dma_attrs *attrs);
+			   dma_addr_t, size_t, unsigned long attrs);
 
 	dma_addr_t (*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);
 	void (*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);
 	/*
 	 * map_sg returns 0 on error and a value > 0 on success.
 	 * It should never return a value < 0.
 	 */
 	int (*map_sg)(struct device *dev, struct scatterlist *sg,
 		      int nents, enum dma_data_direction dir,
-		      struct dma_attrs *attrs);
+		      unsigned long attrs);
 	void (*unmap_sg)(struct device *dev,
 			 struct scatterlist *sg, int nents,
 			 enum dma_data_direction dir,
-			 struct dma_attrs *attrs);
+			 unsigned long attrs);
 	void (*sync_single_for_cpu)(struct device *dev,
 				    dma_addr_t dma_handle, size_t size,
 				    enum dma_data_direction dir);
@@ -123,7 +169,7 @@ static inline struct dma_map_ops *get_dma_ops(struct device *dev)
 static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
 					      size_t size,
 					      enum dma_data_direction dir,
-					      struct dma_attrs *attrs)
+					      unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 	dma_addr_t addr;
@@ -142,7 +188,7 @@ static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
 static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
 					  size_t size,
 					  enum dma_data_direction dir,
-					  struct dma_attrs *attrs)
+					  unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 
@@ -158,7 +204,7 @@ static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
  */
 static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
 				   int nents, enum dma_data_direction dir,
-				   struct dma_attrs *attrs)
+				   unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 	int i, ents;
@@ -176,7 +222,7 @@ static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
 
 static inline void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg,
 				      int nents, enum dma_data_direction dir,
-				      struct dma_attrs *attrs)
+				      unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 
@@ -195,7 +241,7 @@ static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
 
 	kmemcheck_mark_initialized(page_address(page) + offset, size);
 	BUG_ON(!valid_dma_direction(dir));
-	addr = ops->map_page(dev, page, offset, size, dir, NULL);
+	addr = ops->map_page(dev, page, offset, size, dir, 0);
 	debug_dma_map_page(dev, page, offset, size, dir, addr, false);
 
 	return addr;
@@ -208,7 +254,7 @@ static inline void dma_unmap_page(struct device *dev, dma_addr_t addr,
 
 	BUG_ON(!valid_dma_direction(dir));
 	if (ops->unmap_page)
-		ops->unmap_page(dev, addr, size, dir, NULL);
+		ops->unmap_page(dev, addr, size, dir, 0);
 	debug_dma_unmap_page(dev, addr, size, dir, false);
 }
 
@@ -289,10 +335,10 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 
 }
 
-#define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, NULL)
-#define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, NULL)
-#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, NULL)
-#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, NULL)
+#define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, 0)
+#define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, 0)
+#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, 0)
+#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, 0)
 
 extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
 			   void *cpu_addr, dma_addr_t dma_addr, size_t size);
@@ -321,7 +367,7 @@ void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags);
  */
 static inline int
 dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr,
-	       dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs)
+	       dma_addr_t dma_addr, size_t size, unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 	BUG_ON(!ops);
@@ -330,7 +376,7 @@ dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma, void *cpu_addr,
 	return dma_common_mmap(dev, vma, cpu_addr, dma_addr, size);
 }
 
-#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, NULL)
+#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, 0)
 
 int
 dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
@@ -338,7 +384,8 @@ dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
 
 static inline int
 dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr,
-		      dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs)
+		      dma_addr_t dma_addr, size_t size,
+		      unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 	BUG_ON(!ops);
@@ -348,7 +395,7 @@ dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr,
 	return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size);
 }
 
-#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, NULL)
+#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, 0)
 
 #ifndef arch_dma_alloc_attrs
 #define arch_dma_alloc_attrs(dev, flag)	(true)
@@ -356,7 +403,7 @@ dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr,
 
 static inline void *dma_alloc_attrs(struct device *dev, size_t size,
 				       dma_addr_t *dma_handle, gfp_t flag,
-				       struct dma_attrs *attrs)
+				       unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 	void *cpu_addr;
@@ -378,7 +425,7 @@ static inline void *dma_alloc_attrs(struct device *dev, size_t size,
 
 static inline void dma_free_attrs(struct device *dev, size_t size,
 				     void *cpu_addr, dma_addr_t dma_handle,
-				     struct dma_attrs *attrs)
+				     unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 
@@ -398,31 +445,27 @@ static inline void dma_free_attrs(struct device *dev, size_t size,
 static inline void *dma_alloc_coherent(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, gfp_t flag)
 {
-	return dma_alloc_attrs(dev, size, dma_handle, flag, NULL);
+	return dma_alloc_attrs(dev, size, dma_handle, flag, 0);
 }
 
 static inline void dma_free_coherent(struct device *dev, size_t size,
 		void *cpu_addr, dma_addr_t dma_handle)
 {
-	return dma_free_attrs(dev, size, cpu_addr, dma_handle, NULL);
+	return dma_free_attrs(dev, size, cpu_addr, dma_handle, 0);
 }
 
 static inline void *dma_alloc_noncoherent(struct device *dev, size_t size,
 		dma_addr_t *dma_handle, gfp_t gfp)
 {
-	DEFINE_DMA_ATTRS(attrs);
-
-	dma_set_attr(DMA_ATTR_NON_CONSISTENT, &attrs);
-	return dma_alloc_attrs(dev, size, dma_handle, gfp, &attrs);
+	return dma_alloc_attrs(dev, size, dma_handle, gfp,
+			       DMA_ATTR_NON_CONSISTENT);
 }
 
 static inline void dma_free_noncoherent(struct device *dev, size_t size,
 		void *cpu_addr, dma_addr_t dma_handle)
 {
-	DEFINE_DMA_ATTRS(attrs);
-
-	dma_set_attr(DMA_ATTR_NON_CONSISTENT, &attrs);
-	dma_free_attrs(dev, size, cpu_addr, dma_handle, &attrs);
+	dma_free_attrs(dev, size, cpu_addr, dma_handle,
+		       DMA_ATTR_NON_CONSISTENT);
 }
 
 static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
@@ -646,9 +689,8 @@ static inline void dmam_release_declared_memory(struct device *dev)
 static inline void *dma_alloc_wc(struct device *dev, size_t size,
 				 dma_addr_t *dma_addr, gfp_t gfp)
 {
-	DEFINE_DMA_ATTRS(attrs);
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
-	return dma_alloc_attrs(dev, size, dma_addr, gfp, &attrs);
+	return dma_alloc_attrs(dev, size, dma_addr, gfp,
+			       DMA_ATTR_WRITE_COMBINE);
 }
 #ifndef dma_alloc_writecombine
 #define dma_alloc_writecombine dma_alloc_wc
@@ -657,9 +699,8 @@ static inline void *dma_alloc_wc(struct device *dev, size_t size,
 static inline void dma_free_wc(struct device *dev, size_t size,
 			       void *cpu_addr, dma_addr_t dma_addr)
 {
-	DEFINE_DMA_ATTRS(attrs);
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
-	return dma_free_attrs(dev, size, cpu_addr, dma_addr, &attrs);
+	return dma_free_attrs(dev, size, cpu_addr, dma_addr,
+			      DMA_ATTR_WRITE_COMBINE);
 }
 #ifndef dma_free_writecombine
 #define dma_free_writecombine dma_free_wc
@@ -670,9 +711,8 @@ static inline int dma_mmap_wc(struct device *dev,
 			      void *cpu_addr, dma_addr_t dma_addr,
 			      size_t size)
 {
-	DEFINE_DMA_ATTRS(attrs);
-	dma_set_attr(DMA_ATTR_WRITE_COMBINE, &attrs);
-	return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs);
+	return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size,
+			      DMA_ATTR_WRITE_COMBINE);
 }
 #ifndef dma_mmap_writecombine
 #define dma_mmap_writecombine dma_mmap_wc