Re: [PATCH V3 1/5] RDMA/core: Transport-independent access flags

Jason Gunthorpe
2015-07-24T04:46:45Z

On Fri, Jul 24, 2015 at 12:18:41AM +0000, Hefty, Sean wrote:
> > The lkey is possibly useful if someone wants to do single op transfers
> > larger than the S/G limit of the SQE. I haven't noticed any ULPs doing
> > that..
>
> That changes how the buffer is identified, which gets back to my
> question of are we identifying local buffers by address or through
> some sort of iova/tag/descriptor/mr/whatever. Do we have this right
> in the API?

After Sagi's work, and my patchset, all ULPs will talk about local
buffers in only two ways:
- struct ib_sge w/ local_dma_lkey
- struct scatterlist with memory registration to a simple ib_sge.
(only done for iWarp RDMA READ? Maybe iSER DIX as well?)

Efforts to unify them have not been successful for fairly reasonable
reasons :)

Jason