[openib-general] APM: SM port failover

[Sean Hefty]

Venkatesh Babu wrote:
>  Let us say there are two nodes A and B. NodeA (passive side) passively 
> listens for RC QP connection establishment requests and NodeB (active 
> side) initiates the RC QP connection request with ib_send_cm_req(). When 
> a port failure occurs on NodeA (passive side), it gets the event 
> IB_EVENT_PORT_ERR locally. So it can call ib_modify_qp() for the RC QP 
> to change the path_mig_state to IB_MIG_MIGRATED to use the alternate 
> path. No problem here. But NodeB has to register with the OpenSM for the 
> port failure event on NodeA, so that it can call ib_modify_qp() on the 
> active side.

Note that path migration will occur without either calling ib_modify_qp() to 
force the migration.  ib_modify_qp() can speed up how quickly failover occurs, 
but it is not necessary.

> This is working fine by using the interface ib_sa_serv_notice_hdlr() 
> described in bug#159 
> (https://staging.openfabrics.org/bugzilla/show_bug.cgi?id=159).

InformInfo support has also been added through my rdma-dev git tree.

- Sean