b44: tx bounce sizing.

No need to grap full size MTU buffer for possibly small transmit
bounce buffers.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/b44.c

@@ -69,7 +69,6 @@
 #define NEXT_TX(N)		(((N) + 1) & (B44_TX_RING_SIZE - 1))
 
 #define RX_PKT_BUF_SZ		(1536 + bp->rx_offset + 64)
-#define TX_PKT_BUF_SZ		(B44_MAX_MTU + ETH_HLEN + 8)
 
 /* minimum number of free TX descriptors required to wake up TX process */
 #define B44_TX_WAKEUP_THRESH		(B44_TX_RING_SIZE / 4)
@@ -968,7 +967,6 @@ static void b44_tx_timeout(struct net_device *dev)
 static int b44_start_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct b44 *bp = netdev_priv(dev);
-	struct sk_buff *bounce_skb;
 	int rc = NETDEV_TX_OK;
 	dma_addr_t mapping;
 	u32 len, entry, ctrl;
@@ -986,12 +984,13 @@ static int b44_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	mapping = pci_map_single(bp->pdev, skb->data, len, PCI_DMA_TODEVICE);
 	if (dma_mapping_error(mapping) || mapping + len > DMA_30BIT_MASK) {
+		struct sk_buff *bounce_skb;
+
 		/* Chip can't handle DMA to/from >1GB, use bounce buffer */
 		if (!dma_mapping_error(mapping))
 			pci_unmap_single(bp->pdev, mapping, len, PCI_DMA_TODEVICE);
 
-		bounce_skb = __dev_alloc_skb(TX_PKT_BUF_SZ,
-					     GFP_ATOMIC|GFP_DMA);
+		bounce_skb = __dev_alloc_skb(len, GFP_ATOMIC | GFP_DMA);
 		if (!bounce_skb)
 			goto err_out;
 
@@ -1005,8 +1004,7 @@ static int b44_start_xmit(struct sk_buff *skb, struct net_device *dev)
 			goto err_out;
 		}
 
-		skb_copy_from_linear_data(skb, skb_put(bounce_skb, len),
-					  skb->len);
+		skb_copy_from_linear_data(skb, skb_put(bounce_skb, len), len);
 		dev_kfree_skb_any(skb);
 		skb = bounce_skb;
 	}