IB/mlx4: Update QP state if query QP succeeds

If the QP was moved to another state (such as SQE) by the hardware,
then after this change the user won't have to set the IBV_QP_CUR_STATE
mask in order to execute modify QP in order to recover from this state.
Signed-off-by: Dotan Barak <dotanb@dev.mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mlx4/qp.c

@@ -1785,7 +1785,9 @@ int mlx4_ib_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *qp_attr, int qp_attr
 	struct mlx4_ib_qp *qp = to_mqp(ibqp);
 	struct mlx4_qp_context context;
 	int mlx4_state;
-	int err;
+	int err = 0;
+
+	mutex_lock(&qp->mutex);
 
 	if (qp->state == IB_QPS_RESET) {
 		qp_attr->qp_state = IB_QPS_RESET;
@@ -1793,12 +1795,15 @@ int mlx4_ib_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *qp_attr, int qp_attr
 	}
 
 	err = mlx4_qp_query(dev->dev, &qp->mqp, &context);
-	if (err)
-		return -EINVAL;
+	if (err) {
+		err = -EINVAL;
+		goto out;
+	}
 
 	mlx4_state = be32_to_cpu(context.flags) >> 28;
 
-	qp_attr->qp_state	     = to_ib_qp_state(mlx4_state);
+	qp->state		     = to_ib_qp_state(mlx4_state);
+	qp_attr->qp_state	     = qp->state;
 	qp_attr->path_mtu	     = context.mtu_msgmax >> 5;
 	qp_attr->path_mig_state	     =
 		to_ib_mig_state((be32_to_cpu(context.flags) >> 11) & 0x3);
@@ -1857,6 +1862,8 @@ int mlx4_ib_query_qp(struct ib_qp *ibqp, struct ib_qp_attr *qp_attr, int qp_attr
 
 	qp_init_attr->cap	     = qp_attr->cap;
 
-	return 0;
+out:
+	mutex_unlock(&qp->mutex);
+	return err;
 }