xen-swiotlb: implement ->mapping_error

DMA_ERROR_CODE is going to go away, so don't rely on it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index a0f006daab48..c3a04b2d7532 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -67,6 +67,8 @@ static unsigned long dma_alloc_coherent_mask(struct device *dev,
 }
 #endif
 
+#define XEN_SWIOTLB_ERROR_CODE  (~(dma_addr_t)0x0)
+
 static char *xen_io_tlb_start, *xen_io_tlb_end;
 static unsigned long xen_io_tlb_nslabs;
 /*
@@ -410,7 +412,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
         map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
                                      attrs);
         if (map == SWIOTLB_MAP_ERROR)
-                return DMA_ERROR_CODE;
+                return XEN_SWIOTLB_ERROR_CODE;
 
         dev_addr = xen_phys_to_bus(map);
         xen_dma_map_page(dev, pfn_to_page(map >> PAGE_SHIFT),
@@ -425,7 +427,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
         attrs |= DMA_ATTR_SKIP_CPU_SYNC;
         swiotlb_tbl_unmap_single(dev, map, size, dir, attrs);
 
-        return DMA_ERROR_CODE;
+        return XEN_SWIOTLB_ERROR_CODE;
 }
 
 /*
@@ -715,6 +717,11 @@ xen_swiotlb_get_sgtable(struct device *dev, struct sg_table *sgt,
         return dma_common_get_sgtable(dev, sgt, cpu_addr, handle, size);
 }
 
+static int xen_swiotlb_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+        return dma_addr == XEN_SWIOTLB_ERROR_CODE;
+}
+
 const struct dma_map_ops xen_swiotlb_dma_ops = {
         .alloc = xen_swiotlb_alloc_coherent,
         .free = xen_swiotlb_free_coherent,
@@ -730,4 +737,5 @@ const struct dma_map_ops xen_swiotlb_dma_ops = {
         .set_dma_mask = xen_swiotlb_set_dma_mask,
         .mmap = xen_swiotlb_dma_mmap,
         .get_sgtable = xen_swiotlb_get_sgtable,
+        .mapping_error  = xen_swiotlb_mapping_error,
 };