diff --git a/drivers/net/dl2k.c b/drivers/net/dl2k.c
index 1f3627470c958972da00dcba432fe27fd893788c..1ddefd281213d613462f05a583795921d5d3acd4 100644
--- a/drivers/net/dl2k.c
+++ b/drivers/net/dl2k.c
@@ -765,7 +765,7 @@ rio_free_tx (struct net_device *dev, int irq)
 			break;
 		skb = np->tx_skbuff[entry];
 		pci_unmap_single (np->pdev,
-				  np->tx_ring[entry].fraginfo & 0xffffffffffff,
+				  np->tx_ring[entry].fraginfo & DMA_48BIT_MASK,
 				  skb->len, PCI_DMA_TODEVICE);
 		if (irq)
 			dev_kfree_skb_irq (skb);
@@ -893,7 +893,7 @@ receive_packet (struct net_device *dev)
 			/* Small skbuffs for short packets */
 			if (pkt_len > copy_thresh) {
 				pci_unmap_single (np->pdev,
-						  desc->fraginfo & 0xffffffffffff,
+						  desc->fraginfo & DMA_48BIT_MASK,
 						  np->rx_buf_sz,
 						  PCI_DMA_FROMDEVICE);
 				skb_put (skb = np->rx_skbuff[entry], pkt_len);
@@ -901,7 +901,7 @@ receive_packet (struct net_device *dev)
 			} else if ((skb = dev_alloc_skb (pkt_len + 2)) != NULL) {
 				pci_dma_sync_single_for_cpu(np->pdev,
 				  			    desc->fraginfo & 
-							    	0xffffffffffff,
+							    	DMA_48BIT_MASK,
 							    np->rx_buf_sz,
 							    PCI_DMA_FROMDEVICE);
 				skb->dev = dev;
@@ -913,7 +913,7 @@ receive_packet (struct net_device *dev)
 				skb_put (skb, pkt_len);
 				pci_dma_sync_single_for_device(np->pdev,
 				  			       desc->fraginfo &
-							       	 0xffffffffffff,
+							       	 DMA_48BIT_MASK,
 							       np->rx_buf_sz,
 							       PCI_DMA_FROMDEVICE);
 			}
@@ -1800,7 +1800,7 @@ rio_close (struct net_device *dev)
 		skb = np->rx_skbuff[i];
 		if (skb) {
 			pci_unmap_single(np->pdev, 
-					 np->rx_ring[i].fraginfo & 0xffffffffffff,
+					 np->rx_ring[i].fraginfo & DMA_48BIT_MASK,
 					 skb->len, PCI_DMA_FROMDEVICE);
 			dev_kfree_skb (skb);
 			np->rx_skbuff[i] = NULL;
@@ -1810,7 +1810,7 @@ rio_close (struct net_device *dev)
 		skb = np->tx_skbuff[i];
 		if (skb) {
 			pci_unmap_single(np->pdev, 
-					 np->tx_ring[i].fraginfo & 0xffffffffffff,
+					 np->tx_ring[i].fraginfo & DMA_48BIT_MASK,
 					 skb->len, PCI_DMA_TODEVICE);
 			dev_kfree_skb (skb);
 			np->tx_skbuff[i] = NULL;
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index ff61817082fa80271a24f4b2ad70623c013dfc26..635690cf3e3dc77ff54f8d07555da2ffc4dff165 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -14,6 +14,7 @@ enum dma_data_direction {
 };
 
 #define DMA_64BIT_MASK	0xffffffffffffffffULL
+#define DMA_48BIT_MASK	0x0000ffffffffffffULL
 #define DMA_40BIT_MASK	0x000000ffffffffffULL
 #define DMA_39BIT_MASK	0x0000007fffffffffULL
 #define DMA_32BIT_MASK	0x00000000ffffffffULL