RE: [PATCH RFC] RDMA/core: add rdma_get_dma_mr()

Steve Wise
2015-06-29T13:47:55Z

> -----Original Message-----
> From: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Haggai Eran
> Sent: Sunday, June 28, 2015 10:47 AM
> To: Steve Wise; jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org
> Cc: sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org; roid-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org; ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org; sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org; linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> Subject: Re: [PATCH RFC] RDMA/core: add rdma_get_dma_mr()
>
> On 26/06/2015 00:29, Steve Wise wrote:
> > +enum rdma_mr_roles {
> > + RDMA_MRR_RECV = 1,
> > + RDMA_MRR_SEND = (1<<1),
> > + RDMA_MRR_READ_SOURCE = (1<<2),
> > + RDMA_MRR_READ_SINK = (1<<3),
>
> Maybe it's just me, but it took me a second to figure out which was the
> source and which was the sink in RDMA reads. Do you think calling them
> initiator and responder/target would be better?

Not to me. For an RDMA operation, the "initiator" is the app that issues the read request WR. That app doesn't create what I call the READ_SOURCE MR. Its peer application does. So calling READ_SOURCE something like READ_INITIATOR doesn't make sense to me. That's why I thought SOURCE and SINK were clearer. Perhaps not...

I have a new version I'll send out soon that will comment all of these in the enum declaration. Perhaps that will make it clear.

>
> > + RDMA_MRR_WRITE_SOURCE = (1<<4),
> > + RDMA_MRR_WRITE_SINK = (1<<5),
> > + RDMA_MRR_ATOMIC = (1<<6),
> > + RDMA_MRR_MW_BIND = (1<<7),
> > + RDMA_MRR_ZERO_BASED = (1<<8),
> > + RDMA_MRR_ACCESS_ON_DEMAND = (1<<9),
> > +};
>
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