[Xen-changelog] Do not set jumbo MTU on the fake netfront/back loopback device. It

[BitKeeper Bot <riel@xxxxxxxxxxx>]

ChangeSet 1.1159.258.139, 2005/05/19 15:03:42+01:00, kaf24@xxxxxxxxxxxxxxxxxxxx

        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@xxxxxxxxxxxxx>



 loopback.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletion(-)


diff -Nru a/linux-2.6.11-xen-sparse/drivers/xen/netback/loopback.c 
b/linux-2.6.11-xen-sparse/drivers/xen/netback/loopback.c
--- a/linux-2.6.11-xen-sparse/drivers/xen/netback/loopback.c    2005-05-19 
11:06:06 -04:00
+++ b/linux-2.6.11-xen-sparse/drivers/xen/netback/loopback.c    2005-05-19 
11:06:06 -04:00
@@ -94,7 +94,15 @@
     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)

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