Re: [PATCH 2/2] rdma/cm: allow user to specify IP to DGID mapping

Or Gerlitz
2009-10-08T23:33:56Z

Sean Hefty <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> wrote:
>>When used over IB, the IP address is little more than a qualifier contained
>>within the IB CM REQ private data.
>
> If we added support for AF_GID/AF_IB to the kernel, the rdma_cm could leave all
> of the private data carried in the IB CM REQ entirely up to the user.  If the
> user happens to format that data to look like the CMA header, so be it.  I
> believe this would allow for a 'clean' implementation of rdma_resolve_addr,
> preserve the ABI, and still allow a library to provide backwards compatibility.

Sean,

So in this design librdmacm will change the user supplied AF_XXX in
the provided sock address and set it to AF_GID/IB, sounds okay.

> Would this approach combined with the ability to set the route work for everyone?

yes, it makes sense.

However, I don't manage to follow on your port space discussion with
Jason. Some apps may have client in user space and server in the
kernel or vise versa. I wouldn't tie PS_IB or a like with ACM. The ACM
ARP replacement protocol will reply only if the ip address specified
in the broadcast request is an ip of this host on that pkey and a port
connected to that fabric, correct?

Or.