RE: [PATCH RFC 2/2] RDMA/isert: Support iWARP transport

Steve Wise
2015-06-25T18:32:09Z

> -----Original Message-----
> From: Jason Gunthorpe [mailto:jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org]
> Sent: Thursday, June 25, 2015 1:25 PM
> To: Steve Wise
> Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; sagig-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org; orgerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org; raid-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org
> Subject: Re: [PATCH RFC 2/2] RDMA/isert: Support iWARP transport
>
> On Thu, Jun 25, 2015 at 10:39:23AM -0500, Steve Wise wrote:
> > + /*
> > + * IWARP transports need REMOTE_WRITE for MRs used as the target of
> > + * an RDMA_READ. Since the DMA MR is used for all ports, then if
> > + * any port is running IWARP, add REMOTE_WRITE.
> > + */
> > + if (any_port_is_iwarp(device))
>
> It would be nice to have a new-style cap test for this instead of open
> coding iwarp. Similar to rdma_cap_read_multi_sge
>

That would be ok with me. Now for naming this new function:

rdma_cap_read_requires_remote_write_rights()

That's pretty long. Any other ideas for naming this?

> I'm confused about the 'any_port_is_iwarp' stuff too, I thought if one
> port was iwarp then all ports had to be iwarp?
>

Currently no device supports iwarp + any other protocol.

> Even if we move away from that, I would think that some caps must be
> the same on all ports, and multi_sge, remote_write, etc would fit into
> that limitation.
>

I'm happy with making this a device-global capability. If it becomes a per-port capability, then the code can change later.

Steve.