[rds-devel] net/rds: Add support for RDMA_CM_EVENT_ADDR_CHANGE event

[Or Gerlitz]

> 4) the rdma cm would generate an ADDR CHANGE event as hint for the RDMA
> ULP (eg RDS) that their connection is "not aligned with the IP stack" so
> they should reconnect

Enhance rds to act upon notification on network stack changes that make
its RDMA connection unaligned with the link used by the stack for the
<src,dst> IPs used to establish the connection.

Under ADDR_CHANGE event, issue a connection drop, that is disconnect
the current and attempt to establish a new one such that the new
the new connection will be aligned with the IP stack.

Signed-off-by: Or Gerlitz <ogerlitz at voltaire.com>

Index: linux-2.6.27-rc3/net/rds/ib_cm.c
===================================================================
--- linux-2.6.27-rc3.orig/net/rds/ib_cm.c
+++ linux-2.6.27-rc3/net/rds/ib_cm.c
@@ -581,6 +581,7 @@ static int rds_ib_cm_event_handler(struc
 		case RDMA_CM_EVENT_UNREACHABLE:
 		case RDMA_CM_EVENT_REJECTED:
 		case RDMA_CM_EVENT_DEVICE_REMOVAL:
+		case RDMA_CM_EVENT_ADDR_CHANGE:
 			if (conn)
 				rds_conn_drop(conn);
 			break;