As a first step to making DMA_ATTR_SKIP_CPU_SYNC apply to architectures
beyond just ARM I need to make it so that the swiotlb will respect the
flag.  In order to do that I also need to update the swiotlb-xen since it
heavily makes use of the functionality.

Cc: Konrad Rzeszutek Wilk <redacted>
Signed-off-by: Alexander Duyck <redacted>
---
 drivers/xen/swiotlb-xen.c |   40 ++++++++++++++++++++++----------------
 include/linux/swiotlb.h   |    6 ++++--
 lib/swiotlb.c             |   48 +++++++++++++++++++++++++++------------------
 3 files changed, 56 insertions(+), 38 deletions(-)

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 87e6035..cf047d8 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c

@@ -405,7 +405,8 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 	 */
 	trace_swiotlb_bounced(dev, dev_addr, size, swiotlb_force);
 
-	map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir);
+	map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
+				     attrs);
 	if (map == SWIOTLB_MAP_ERROR)
 		return DMA_ERROR_CODE;
 

@@ -416,11 +417,13 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 	/*
 	 * Ensure that the address returned is DMA'ble
 	 */
-	if (!dma_capable(dev, dev_addr, size)) {
-		swiotlb_tbl_unmap_single(dev, map, size, dir);
-		dev_addr = 0;
-	}
-	return dev_addr;
+	if (dma_capable(dev, dev_addr, size))
+		return dev_addr;
+
+	swiotlb_tbl_unmap_single(dev, map, size, dir,
+				 attrs | DMA_ATTR_SKIP_CPU_SYNC);
+
+	return DMA_ERROR_CODE;

 }
 EXPORT_SYMBOL_GPL(xen_swiotlb_map_page);
 

@@ -444,7 +447,7 @@ static void xen_unmap_single(struct device *hwdev, dma_addr_t dev_addr,
 
 	/* NOTE: We use dev_addr here, not paddr! */
 	if (is_xen_swiotlb_buffer(dev_addr)) {
-		swiotlb_tbl_unmap_single(hwdev, paddr, size, dir);
+		swiotlb_tbl_unmap_single(hwdev, paddr, size, dir, attrs);
 		return;
 	}
 

@@ -557,16 +560,9 @@ void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
 								 start_dma_addr,
 								 sg_phys(sg),
 								 sg->length,
-								 dir);
-			if (map == SWIOTLB_MAP_ERROR) {
-				dev_warn(hwdev, "swiotlb buffer is full\n");
-				/* Don't panic here, we expect map_sg users
-				   to do proper error handling. */
-				xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
-							   attrs);
-				sg_dma_len(sgl) = 0;
-				return 0;
-			}
+								 dir, attrs);
+			if (map == SWIOTLB_MAP_ERROR)
+				goto map_error;
 			xen_dma_map_page(hwdev, pfn_to_page(map >> PAGE_SHIFT),
 						dev_addr,
 						map & ~PAGE_MASK,

@@ -589,6 +585,16 @@ void xen_swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
 		sg_dma_len(sg) = sg->length;
 	}
 	return nelems;
+map_error:
+	dev_warn(hwdev, "swiotlb buffer is full\n");
+	/*
+	 * Don't panic here, we expect map_sg users
+	 * to do proper error handling.
+	 */
+	xen_swiotlb_unmap_sg_attrs(hwdev, sgl, i, dir,
+				   attrs | DMA_ATTR_SKIP_CPU_SYNC);
+	sg_dma_len(sgl) = 0;
+	return 0;
 }