pcnet32: Fix PCnet32 performance bug on non-coherent architecutres

The PCnet32 driver always passed the the size of the largest possible packet
to the pci_dma_sync_single_for_cpu and pci_dma_sync_single_for_device.
This results in a fairly large "colateral damage" in the caches and makes
the flush operation itself much slower.  On a system with a 40MHz CPU this
patch increases network bandwidth by about 12%.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Don Fry <pcnet32@verizon.net>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

diff --git a/drivers/net/pcnet32.c b/drivers/net/pcnet32.c
index 36f9d98..4d94ba7 100644 (file)
--- a/drivers/net/pcnet32.c
+++ b/drivers/net/pcnet32.c
@@ -1234,14 +1234,14 @@ static void pcnet32_rx_entry(struct net_device *dev,
                skb_put(skb, pkt_len);  /* Make room */
                pci_dma_sync_single_for_cpu(lp->pci_dev,
                                            lp->rx_dma_addr[entry],
-                                           PKT_BUF_SZ - 2,
+                                           pkt_len,
                                            PCI_DMA_FROMDEVICE);
                eth_copy_and_sum(skb,
                                 (unsigned char *)(lp->rx_skbuff[entry]->data),
                                 pkt_len, 0);
                pci_dma_sync_single_for_device(lp->pci_dev,
                                               lp->rx_dma_addr[entry],
-                                              PKT_BUF_SZ - 2,
+                                              pkt_len,
                                               PCI_DMA_FROMDEVICE);
        }
        lp->stats.rx_bytes += skb->len;