RDMA/cxgb4: Make sure flush CQ entries are collected on connection close

At the time when a peer closes the connection, iw_cxgb4 will not send
a cq event if ibqp.uobject exists.  In that case, its possible for a
user application to get blocked in ibv_get_cq_event().

To resolve this, call the cq's comp_handler to unblock any read from
ibv_get_cq_event().  This will trigger userspace to poll the cq and
collect flush status completions for any pending work requests.
Signed-off-by: Kumar Sanghvi <kumaras@chelsio.com>
Acked-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/cxgb4/qp.c

@@ -966,8 +966,12 @@ static void flush_qp(struct c4iw_qp *qhp)
 	if (qhp->ibqp.uobject) {
 		t4_set_wq_in_error(&qhp->wq);
 		t4_set_cq_in_error(&rchp->cq);
-		if (schp != rchp)
+		(*rchp->ibcq.comp_handler)(&rchp->ibcq, rchp->ibcq.cq_context);
+		if (schp != rchp) {
 			t4_set_cq_in_error(&schp->cq);
+			(*schp->ibcq.comp_handler)(&schp->ibcq,
+					schp->ibcq.cq_context);
+		}
 		return;
 	}
 	__flush_qp(qhp, rchp, schp);