bitkeeper revision 1.1159.258.139 (428c9cbe7Sc87xp33OYAeObd7e3N3g)

Do not set jumbo MTU on the fake netfront/back loopback device. It
causes packet loss at the Ethernet bridge (since bridges do not
fragment IP packets).
Signed-off-by: Keir Fraser <keir@xensource.com>

diff --git a/linux-2.6.11-xen-sparse/drivers/xen/netback/loopback.c b/linux-2.6.11-xen-sparse/drivers/xen/netback/loopback.c
index 9dffff0fc2b5b78e5ef02af0b2cd3305d25b7f07..ebada3721ab09eed4bde4d6c858deb98b332f0eb 100644 (file)
--- a/linux-2.6.11-xen-sparse/drivers/xen/netback/loopback.c
+++ b/linux-2.6.11-xen-sparse/drivers/xen/netback/loopback.c
@@ -94,7 +94,15 @@ static void loopback_construct(struct net_device *dev, struct net_device *lo)
     dev->get_stats       = loopback_get_stats;
 
     dev->tx_queue_len    = 0;
-    dev->mtu             = 16*1024;
+
+    /*
+     * We do not set a jumbo MTU on the interface. Otherwise the network
+     * stack will try to send large packets that will get dropped by the
+     * Ethernet bridge (unless the physical Ethernet interface is configured
+     * to transfer jumbo packets). If a larger MTU is desired then the system
+     * administrator can specify it using the 'ifconfig' command.
+     */
+    /*dev->mtu             = 16*1024;*/
 }
 
 static int __init loopback_init(void)