[rds-devel] IB/iWARP code separation

[Or Gerlitz]

On Thu, Nov 6, 2008 at 11:44 PM, Steve Wise <swise at opengridcomputing.com> wrote:

>> So Rick's thought about the impossibility to reclaim the buffer at the
>> side initiating the rdma following the completion was wrong, I see.

> He might have been talking about more than just reclaiming the buffer.

In that context he mentioned two issues: current RDS design/code
assumes for rdma completion to indicates that (1) buffer ownership is
returned to client (2) rdma has been processed by remote HCA - and is
pending delivery to remote host memory.

>From your other reply I understand that the buffer can be reclaimed,
and from Rick response I understand that he's thinking on submitting
0bread following rdma-write to address the 2nd requirement. So it
seems we are done in that respect.

> Async events. In the iWARP RDMAP protocol, any ingress errors (like bad stag on an
> incoming write or read response) result in a TERMINATE message sent back to
> the peer (and then the connection torn down).  The peer who gets the
> TERMINATE message will map that to an async event.  Looks like cxgb3 and amso1100 > map it to IB_EVENT_QP_REQ_ERR, and nes maps it to IB_EVENT_QP_FATAL.

When the connection is torn down - is it somehow notified by the iw cm
at either side? a possible solution would be to terminate the
connection in the ULP (RDS) level when getting such async event, or
maybe have the iw cm also register an async handler and generate
disconnect callback on the CM ID associated with that QP.

Or.