RDMA/cma: Add RDMA_CM_EVENT_ADDR_CHANGE event

Add an RDMA_CM_EVENT_ADDR_CHANGE event can be used by rdma-cm
consumers that wish to have their RDMA sessions always use the same
links (eg <hca/port>) as the IP stack does.  In the current code, this
does not happen when bonding is used and fail-over happened but the IB
link used by an already existing session is operating fine.

Use the netevent notification for sensing that a change has happened
in the IP stack, then scan the rdma-cm ID list to see if there is an
ID that is "misaligned" with respect to the IP stack, and deliver
RDMA_CM_EVENT_ADDR_CHANGE for this ID.  The consumer can act on the
event or just ignore it.

Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/rdma/rdma_cm.h b/include/rdma/rdma_cm.h
index 22bb2e7bab1a..001d606517ff 100644
--- a/include/rdma/rdma_cm.h
+++ b/include/rdma/rdma_cm.h
@@ -57,7 +57,8 @@ enum rdma_cm_event_type {
         RDMA_CM_EVENT_DISCONNECTED,
         RDMA_CM_EVENT_DEVICE_REMOVAL,
         RDMA_CM_EVENT_MULTICAST_JOIN,
-        RDMA_CM_EVENT_MULTICAST_ERROR
+        RDMA_CM_EVENT_MULTICAST_ERROR,
+        RDMA_CM_EVENT_ADDR_CHANGE
 };
 
 enum rdma_port_space {