IB/mlx4: Initialize send queue entry ownership bits

We need to initialize the owner bit of send queue WQEs to hardware 
ownership whenever the QP is modified from reset to init, not just 
when the QP is first allocated.  This avoids having the hardware 
process stale WQEs when the QP is moved to reset but not destroyed and 
then modified to init again. 
Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mlx4/qp.c

@@ -270,9 +270,7 @@ static int create_qp_common(struct mlx4_ib_dev *dev, struct ib_pd *pd,
 			    struct ib_qp_init_attr *init_attr,
 			    struct ib_udata *udata, int sqpn, struct mlx4_ib_qp *qp)
 {
-	struct mlx4_wqe_ctrl_seg *ctrl;
 	int err;
-	int i;
 
 	mutex_init(&qp->mutex);
 	spin_lock_init(&qp->sq.lock);
@@ -352,11 +350,6 @@ static int create_qp_common(struct mlx4_ib_dev *dev, struct ib_pd *pd,
 		if (err)
 			goto err_mtt;
 
-		for (i = 0; i < qp->sq.max; ++i) {
-			ctrl = get_send_wqe(qp, i);
-			ctrl->owner_opcode = cpu_to_be32(1 << 31);
-		}
-
 		qp->sq.wrid  = kmalloc(qp->sq.max * sizeof (u64), GFP_KERNEL);
 		qp->rq.wrid  = kmalloc(qp->rq.max * sizeof (u64), GFP_KERNEL);
 
@@ -878,6 +871,21 @@ static int __mlx4_ib_modify_qp(struct ib_qp *ibqp,
 	else
 		sqd_event = 0;
 
+	/*
+	 * Before passing a kernel QP to the HW, make sure that the
+	 * ownership bits of the send queue are set so that the
+	 * hardware doesn't start processing stale work requests.
+	 */
+	if (!ibqp->uobject && cur_state == IB_QPS_RESET && new_state == IB_QPS_INIT) {
+		struct mlx4_wqe_ctrl_seg *ctrl;
+		int i;
+
+		for (i = 0; i < qp->sq.max; ++i) {
+			ctrl = get_send_wqe(qp, i);
+			ctrl->owner_opcode = cpu_to_be32(1 << 31);
+		}
+	}
+
 	err = mlx4_qp_modify(dev->dev, &qp->mtt, to_mlx4_state(cur_state),
 			     to_mlx4_state(new_state), context, optpar,
 			     sqd_event, &qp->mqp);