[Xen-changelog] [linux-2.6.18-xen] netfront/back: do not mark packets of length < MSS as GSO

["Xen patchbot-linux-2.6.18-xen" <patchbot-linux-2.6.18-xen@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1231859874 0
# Node ID 107e10e0e07c3984630b8d3eaecb5bb957be387a
# Parent  28acedb66302a29c9ef14a3084b4736d3fc192f1
netfront/back: do not mark packets of length < MSS as GSO

Linux assumes that skbs marked for GSO are longer than MSS. In
particular tcp_tso_segment assumes that skb_segment will return a
chain of at least 2 skbs.

Both netfront and back should therefor not pass such a packet up the
stack.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
---
 drivers/xen/netback/netback.c   |    5 +++++
 drivers/xen/netfront/netfront.c |    8 ++++++++
 2 files changed, 13 insertions(+)

diff -r 28acedb66302 -r 107e10e0e07c drivers/xen/netback/netback.c
--- a/drivers/xen/netback/netback.c     Wed Jan 07 12:21:54 2009 +0900
+++ b/drivers/xen/netback/netback.c     Tue Jan 13 15:17:54 2009 +0000
@@ -1345,6 +1345,11 @@ static void net_tx_action(unsigned long 
                        skb_shinfo(skb)->frags[0].page = (void *)~0UL;
                }
 
+               if (skb->data_len < skb_shinfo(skb)->gso_size) {
+                       skb_shinfo(skb)->gso_size = 0;
+                       skb_shinfo(skb)->gso_type = 0;
+               }
+
                __skb_queue_tail(&tx_queue, skb);
 
                pending_cons++;
diff -r 28acedb66302 -r 107e10e0e07c drivers/xen/netfront/netfront.c
--- a/drivers/xen/netfront/netfront.c   Wed Jan 07 12:21:54 2009 +0900
+++ b/drivers/xen/netfront/netfront.c   Tue Jan 13 15:17:54 2009 +0000
@@ -1439,6 +1439,14 @@ err:
                np->stats.rx_packets++;
                np->stats.rx_bytes += skb->len;
 
+#if HAVE_TSO
+               if (skb->data_len < skb_shinfo(skb)->gso_size) {
+                       skb_shinfo(skb)->gso_size = 0;
+#if HAVE_GSO
+                       skb_shinfo(skb)->gso_type = 0;
+#endif
+               }
+#endif
                __skb_queue_tail(&rxq, skb);
 
                np->rx.rsp_cons = ++i;

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