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

Ralph Campbell ralph.campbell at qlogic.com
Wed Aug 13 13:27:49 PDT 2008


On Tue, 2008-08-12 at 11:40 -0700, Roland Dreier wrote:
> > 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.

OK. I will withdraw this patch and make sure any needed changes
are in OpenMPI.




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