[ofa-general] Re: [PATCH for-2.6.27 1/2] RDMA/Core: Add local dma lkey support.

[Steve Wise]

Roland Dreier wrote:
>  > RDS and NFSRDMA will use the local_dma_lkey if the device supports it.
>  > If not, it will use a dma_mr with local access rights.  So using the
>  > local_dma_lkey is just an optimization to avoid allocating a
>  > local-access-only dma_mr.
>
> I wonder if it's worth it... the alternative would be for cxgb3 etc. to
> just return STag 0 from get_dma_mr if only local access rights are
> requested.  But of course as we discussed later STag 0 doesn't do PD
> protection, if anyone cared.
>
>   

I assumed that since the PD protection couldn't be enforced, that cxgb3 
shouldn't take this approach.  But yea, if we ignore the pd issue, cxgb3 
could hide this in a dma-mr, for local access only.

Stevo.