IB/ehca: Filter PATH_MIG events if QP was never armed

Certain firmware versions sometimes cause spurious PATH_MIG events to
occur during QP creation.  Filter these events by making sure PATH_MIG
events are only handed down when they actually make sense (i.e. when
the QP has been armed at least once).
Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/ehca/ehca_classes.h

@@ -194,6 +194,7 @@ struct ehca_qp {
 	u32 packet_count;
 	atomic_t nr_events; /* events seen */
 	wait_queue_head_t wait_completion;
+	int mig_armed;
 };
 
 #define IS_SRQ(qp) (qp->ext_type == EQPT_SRQ)

drivers/infiniband/hw/ehca/ehca_irq.c

@@ -178,6 +178,10 @@ static void dispatch_qp_event(struct ehca_shca *shca, struct ehca_qp *qp,
 {
 	struct ib_event event;
 
+	/* PATH_MIG without the QP ever having been armed is false alarm */
+	if (event_type == IB_EVENT_PATH_MIG && !qp->mig_armed)
+		return;
+
 	event.device = &shca->ib_device;
 	event.event = event_type;
 

drivers/infiniband/hw/ehca/ehca_qp.c

@@ -1460,6 +1460,8 @@ static int internal_modify_qp(struct ib_qp *ibqp,
 			goto modify_qp_exit2;
 		}
 		mqpcb->path_migration_state = attr->path_mig_state + 1;
+		if (attr->path_mig_state == IB_MIG_REARM)
+			my_qp->mig_armed = 1;
 		update_mask |=
 			EHCA_BMASK_SET(MQPCB_MASK_PATH_MIGRATION_STATE, 1);
 	}