[openib-general] Re: IPoIB MTU Changing

[Hal Rosenstock]

On Thu, 2005-06-09 at 12:13, Roland Dreier wrote: 
> I take that back.  I believe the code is correct as it stands.  There
> are two MTU values we keep track of: admin_mtu, requested by the user,
> and mcast_mtu, calculated from the link MTU.  We use the lower of the
> two values.  This allows the user to set an MTU and not have the
> setting lost if the broadcast multicast join completes afterwards.

Yes, the multicast MTU could further trim this down but the admin MTU
appears to be currently capped at IPOIB_PACKET_SIZE - IPOIB_ENCAP_LEN.
That's OK for a 2K link MTU but if the link were negotiated at 4K MTU,
shouldn't this be allowed to be larger if requested ?

-- Hal