From: Ivan Vecera <ivecera@redhat.com>
Date: Fri, 4 Sep 2009 14:52:58 +0200
Subject: [net] r8169: balance pci_map/unmap pair, use hw padding
Message-id: 1252068778-6015-1-git-send-email-ivecera@redhat.com
O-Subject: [RHEL5.5 PATCH] r8169: balance pci_map/pci_unmap pair and use hardware auto-padding
Bugzilla: 515857
RH-Acked-by: Jiri Pirko <jpirko@redhat.com>
RH-Acked-by: Neil Horman <nhorman@redhat.com>
RH-Acked-by: Michal Schmidt <mschmidt@redhat.com>

BZs:
#515857 - flood ping cause out-of-iommu error and panic when mtu larger than 1500

Description:
This patch fixes the pci_unmap_single leak that causes a system panic when
MTU larger than 1500 is used. Also fixes another pci_unmap leak with padded
skb, in this case we can use hardware auto-padding.

Upstream commits:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a866bbf6aacf95f849810079442a20be118ce905
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=97d477a914b146e7e6722ded21afa79886ae8ccd

Test status:
Tested successfully by myself and also by bug reporter.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>

diff --git a/drivers/net/r8169.c b/drivers/net/r8169.c
index 48ca235..c8ebaee 100644
--- a/drivers/net/r8169.c
+++ b/drivers/net/r8169.c
@@ -3239,13 +3239,6 @@ static int rtl8169_start_xmit(struct sk_buff *skb, struct net_device *dev)
 		opts1 |= FirstFrag;
 	} else {
 		len = skb->len;
-
-		if (unlikely(len < ETH_ZLEN)) {
-			if (skb_padto(skb, ETH_ZLEN))
-				goto err_update_stats;
-			len = ETH_ZLEN;
-		}
-
 		opts1 |= FirstFrag | LastFrag;
 		tp->tx_skb[entry].skb = skb;
 	}
@@ -3283,7 +3276,6 @@ out:
 err_stop:
 	netif_stop_queue(dev);
 	ret = NETDEV_TX_BUSY;
-err_update_stats:
 	tp->stats.tx_dropped++;
 	goto out;
 }
@@ -3495,7 +3487,7 @@ static int rtl8169_rx_interrupt(struct net_device *dev,
 					pkt_size, PCI_DMA_FROMDEVICE);
 				rtl8169_mark_to_asic(desc, tp->rx_buf_sz);
 			} else {
-				pci_unmap_single(pdev, addr, pkt_size,
+				pci_unmap_single(pdev, addr, tp->rx_buf_sz,
 						 PCI_DMA_FROMDEVICE);
 				tp->Rx_skbuff[entry] = NULL;
 			}