Date: Wed, 2 Nov 2016 21:09:44 +0100 From: Stefan Richter Subject: firewire: net: max MTU off by one The latest max_mtu patch missed that datagram_size is actually one less than the datagram's Total Length. Fixes: 357f4aae859b ("firewire: net: really fix maximum possible MTU") Signed-off-by: Stefan Richter --- To be applied after net-next was merged. drivers/firewire/net.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/drivers/firewire/net.c +++ b/drivers/firewire/net.c @@ -1480,9 +1480,14 @@ static int fwnet_probe(struct fw_unit *u goto out; dev->local_fifo = dev->handler.offset; + /* + * default MTU: RFC 2734 cl. 4, RFC 3146 cl. 4 + * maximum MTU: RFC 2734 cl. 4.2, fragment encapsulation header's + * maximum possible datagram_size + 1 = 0xfff + 1 + */ net->mtu = 1500U; net->min_mtu = ETH_MIN_MTU; - net->max_mtu = 0xfff; + net->max_mtu = 4096U; /* Set our hardware address while we're at it */ ha = (union fwnet_hwaddr *)net->dev_addr;