IB/mlx4: Do not allow APM under RoCE

Automatic Path Migration is not supported under RoCE. Therefore,
return a "not-supported" error if the caller attempts to set an
alternate path in a QP context.

In addition, if there are no IB ports configured, do not report
APM capability in the device flags returned by mlx4_ib_query_device.
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/mlx4/main.c

@@ -120,6 +120,17 @@ static int check_flow_steering_support(struct mlx4_dev *dev)
 	return dmfs;
 }
 
+static int num_ib_ports(struct mlx4_dev *dev)
+{
+	int ib_ports = 0;
+	int i;
+
+	mlx4_foreach_port(i, dev, MLX4_PORT_TYPE_IB)
+		ib_ports++;
+
+	return ib_ports;
+}
+
 static int mlx4_ib_query_device(struct ib_device *ibdev,
 				struct ib_device_attr *props)
 {
@@ -127,6 +138,7 @@ static int mlx4_ib_query_device(struct ib_device *ibdev,
 	struct ib_smp *in_mad  = NULL;
 	struct ib_smp *out_mad = NULL;
 	int err = -ENOMEM;
+	int have_ib_ports;
 
 	in_mad  = kzalloc(sizeof *in_mad, GFP_KERNEL);
 	out_mad = kmalloc(sizeof *out_mad, GFP_KERNEL);
@@ -143,6 +155,8 @@ static int mlx4_ib_query_device(struct ib_device *ibdev,
 
 	memset(props, 0, sizeof *props);
 
+	have_ib_ports = num_ib_ports(dev->dev);
+
 	props->fw_ver = dev->dev->caps.fw_ver;
 	props->device_cap_flags    = IB_DEVICE_CHANGE_PHY_PORT |
 		IB_DEVICE_PORT_ACTIVE_EVENT		|
@@ -153,7 +167,7 @@ static int mlx4_ib_query_device(struct ib_device *ibdev,
 		props->device_cap_flags |= IB_DEVICE_BAD_PKEY_CNTR;
 	if (dev->dev->caps.flags & MLX4_DEV_CAP_FLAG_BAD_QKEY_CNTR)
 		props->device_cap_flags |= IB_DEVICE_BAD_QKEY_CNTR;
-	if (dev->dev->caps.flags & MLX4_DEV_CAP_FLAG_APM)
+	if (dev->dev->caps.flags & MLX4_DEV_CAP_FLAG_APM && have_ib_ports)
 		props->device_cap_flags |= IB_DEVICE_AUTO_PATH_MIG;
 	if (dev->dev->caps.flags & MLX4_DEV_CAP_FLAG_UD_AV_PORT)
 		props->device_cap_flags |= IB_DEVICE_UD_AV_PORT_ENFORCE;

drivers/infiniband/hw/mlx4/qp.c

@@ -1424,6 +1424,12 @@ static int __mlx4_ib_modify_qp(struct ib_qp *ibqp,
 	int steer_qp = 0;
 	int err = -EINVAL;
 
+	/* APM is not supported under RoCE */
+	if (attr_mask & IB_QP_ALT_PATH &&
+	    rdma_port_get_link_layer(&dev->ib_dev, qp->port) ==
+	    IB_LINK_LAYER_ETHERNET)
+		return -ENOTSUPP;
+
 	context = kzalloc(sizeof *context, GFP_KERNEL);
 	if (!context)
 		return -ENOMEM;