Re: [PATCH v2] RDMA/CMA: fix iWARP adapter TCP port space usage

Steve Wise
2010-06-11T23:40:33Z

Jason Gunthorpe wrote:
> On Fri, Jun 11, 2010 at 03:08:20PM -0700, Roland Dreier wrote:
>
>
>> If Dave Miller says this is an unacceptable thing to merge, then I'm not
>> going to merge it over his explicit and unequivocal NAK. Trying sneak
>> this in by hiding this patch on linux-rdma without cc-ing netdev is the
>> wrong approach... the right approach is to get the hordes of users being
>> hurt by this issue (if there are such hordes), make a big stink, and
>> force a solution that everyone agrees on.
>>
>
> Right..
>
> What exactly is the end-user harm anyhow? Everything works 100%
> correctly without this patch, and your arguments all revolved around
> diagnostic capability..
>
>

No, everything does not work without this patch. Go read the thread
from 2007 (I posted the URL to it on this thread). I describe exactly
how an application like MPI will get incorrect behavior due to port
space collisions on iWARP HW.

> It is a known weakness that the RDMA stack has crappy visibility. That
> has been talked about before. If you want better visibility then fix
> that by adding netlink stuff to dump out all the QP states, PDs, etc,
> similar to what TCP does.
>

What does this have to do with port space allocation? I agree the rdma
stacks should have tools to dump all that good stuff out for
admins/debugging. But its really not part of this issue IMO.

Steve.

> Jason