dma: add calls for dma_map_page_attrs and dma_unmap_page_attrs

Add support for mapping and unmapping a page with attributes.

The primary use for this is currently to allow for us to pass the
DMA_ATTR_SKIP_CPU_SYNC attribute when mapping and unmapping a page.  On
some architectures such as ARM the synchronization has significant
overhead and if we are already taking care of the sync_for_cpu and
sync_for_device from the driver there isn't much need to handle this in
the map/unmap calls as well.

Link: http://lkml.kernel.org/r/20161110113601.76501.46095.stgit@ahduyck-blue-test.jf.intel.comSigned-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/dma-mapping.h

@@ -243,29 +243,33 @@ static inline void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg
 		ops->unmap_sg(dev, sg, nents, dir, attrs);
 }
 
-static inline dma_addr_t dma_map_page(struct device *dev, struct page *page,
+static inline dma_addr_t dma_map_page_attrs(struct device *dev,
+					    struct page *page,
 					    size_t offset, size_t size,
-				      enum dma_data_direction dir)
+					    enum dma_data_direction dir,
+					    unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 	dma_addr_t addr;
 
 	kmemcheck_mark_initialized(page_address(page) + offset, size);
 	BUG_ON(!valid_dma_direction(dir));
-	addr = ops->map_page(dev, page, offset, size, dir, 0);
+	addr = ops->map_page(dev, page, offset, size, dir, attrs);
 	debug_dma_map_page(dev, page, offset, size, dir, addr, false);
 
 	return addr;
 }
 
-static inline void dma_unmap_page(struct device *dev, dma_addr_t addr,
-				  size_t size, enum dma_data_direction dir)
+static inline void dma_unmap_page_attrs(struct device *dev,
+					dma_addr_t addr, size_t size,
+					enum dma_data_direction dir,
+					unsigned long attrs)
 {
 	struct dma_map_ops *ops = get_dma_ops(dev);
 
 	BUG_ON(!valid_dma_direction(dir));
 	if (ops->unmap_page)
-		ops->unmap_page(dev, addr, size, dir, 0);
+		ops->unmap_page(dev, addr, size, dir, attrs);
 	debug_dma_unmap_page(dev, addr, size, dir, false);
 }
 
@@ -385,6 +389,8 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 #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)
+#define dma_map_page(d, p, o, s, r) dma_map_page_attrs(d, p, o, s, r, 0)
+#define dma_unmap_page(d, a, s, r) dma_unmap_page_attrs(d, a, s, 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);