Check for bad dma address in b44 1GB DMA workaround

Signed-off-by: Andi Kleen <ak@suse.de>

---
 drivers/net/b44.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletion(-)

Index: linux/drivers/net/b44.c
===================================================================
--- linux.orig/drivers/net/b44.c
+++ linux/drivers/net/b44.c
@@ -650,7 +650,8 @@ static int b44_alloc_rx_skb(struct b44 *
 
 	/* Hardware bug work-around, the chip is unable to do PCI DMA
 	   to/from anything above 1GB :-( */
-	if (mapping + RX_PKT_BUF_SZ > B44_DMA_MASK) {
+	if (dma_mapping_error(mapping) ||
+		mapping + RX_PKT_BUF_SZ > B44_DMA_MASK) {
 		/* Sigh... */
 		pci_unmap_single(bp->pdev, mapping, RX_PKT_BUF_SZ,PCI_DMA_FROMDEVICE);
 		dev_kfree_skb_any(skb);