swiotlb: do not use sg_virt()

Scatterlists containing HighMem pages do not have a useful virtual
address. Use the physical address instead.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

lib/swiotlb.c

@@ -801,10 +801,10 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
 	BUG_ON(dir == DMA_NONE);
 
 	for_each_sg(sgl, sg, nelems, i) {
-		void *addr = sg_virt(sg);
-		dma_addr_t dev_addr = swiotlb_virt_to_bus(hwdev, addr);
+		phys_addr_t paddr = sg_phys(sg);
+		dma_addr_t dev_addr = swiotlb_phys_to_bus(hwdev, paddr);
 
-		if (range_needs_mapping(sg_phys(sg), sg->length) ||
+		if (range_needs_mapping(paddr, sg->length) ||
 		    address_needs_mapping(hwdev, dev_addr, sg->length)) {
 			void *map = map_single(hwdev, sg_phys(sg),
 					       sg->length, dir);
@@ -848,11 +848,11 @@ swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 	BUG_ON(dir == DMA_NONE);
 
 	for_each_sg(sgl, sg, nelems, i) {
-		if (sg->dma_address != swiotlb_virt_to_bus(hwdev, sg_virt(sg)))
+		if (sg->dma_address != swiotlb_phys_to_bus(hwdev, sg_phys(sg)))
 			unmap_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
 				     sg->dma_length, dir);
 		else if (dir == DMA_FROM_DEVICE)
-			dma_mark_clean(sg_virt(sg), sg->dma_length);
+			dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
 	}
 }
 EXPORT_SYMBOL(swiotlb_unmap_sg_attrs);
@@ -882,11 +882,11 @@ swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sgl,
 	BUG_ON(dir == DMA_NONE);
 
 	for_each_sg(sgl, sg, nelems, i) {
-		if (sg->dma_address != swiotlb_virt_to_bus(hwdev, sg_virt(sg)))
+		if (sg->dma_address != swiotlb_phys_to_bus(hwdev, sg_phys(sg)))
 			sync_single(hwdev, swiotlb_bus_to_virt(sg->dma_address),
 				    sg->dma_length, dir, target);
 		else if (dir == DMA_FROM_DEVICE)
-			dma_mark_clean(sg_virt(sg), sg->dma_length);
+			dma_mark_clean(swiotlb_bus_to_virt(sg->dma_address), sg->dma_length);
 	}
 }