[ofa-general] [PATCH] IB/ipath - don't allow the QP path MTU to be set higher than port MTU

[Roland Dreier]

 > This patch fixes the problem by returning an error when attempting
 > to set the QP path MTU greater than the port MTU.

I don't believe this is correct according to the IB spec -- modify QP is
supposed to return an error only when the requested MTU is bigger than
the MTUcap of the port.  Even if we do have this patch, it seems there
could still be trouble if an intermediate hop has a smaller MTU.

Why is Open MPI trying to set a path MTU bigger than what the fabric
actually supports?

 - R.