IB/core: Add link layer property to ports

This patch allows ports to have different link layers:
IB_LINK_LAYER_INFINIBAND or IB_LINK_LAYER_ETHERNET.  This is required
for adding IBoE (InfiniBand-over-Ethernet, aka RoCE) support.  For
devices that do not provide an implementation for querying the link
layer property of a port, we return a default value based on the
transport: RMA_TRANSPORT_IB nodes will return IB_LINK_LAYER_INFINIBAND
and RDMA_TRANSPORT_IWARP nodes will return IB_LINK_LAYER_ETHERNET.
Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/core/verbs.c

@@ -94,6 +94,22 @@ rdma_node_get_transport(enum rdma_node_type node_type)
 }
 EXPORT_SYMBOL(rdma_node_get_transport);
 
+enum rdma_link_layer rdma_port_get_link_layer(struct ib_device *device, u8 port_num)
+{
+	if (device->get_link_layer)
+		return device->get_link_layer(device, port_num);
+
+	switch (rdma_node_get_transport(device->node_type)) {
+	case RDMA_TRANSPORT_IB:
+		return IB_LINK_LAYER_INFINIBAND;
+	case RDMA_TRANSPORT_IWARP:
+		return IB_LINK_LAYER_ETHERNET;
+	default:
+		return IB_LINK_LAYER_UNSPECIFIED;
+	}
+}
+EXPORT_SYMBOL(rdma_port_get_link_layer);
+
 /* Protection domains */
 
 struct ib_pd *ib_alloc_pd(struct ib_device *device)

include/rdma/ib_verbs.h

@@ -75,6 +75,12 @@ enum rdma_transport_type {
 enum rdma_transport_type
 rdma_node_get_transport(enum rdma_node_type node_type) __attribute_const__;
 
+enum rdma_link_layer {
+	IB_LINK_LAYER_UNSPECIFIED,
+	IB_LINK_LAYER_INFINIBAND,
+	IB_LINK_LAYER_ETHERNET,
+};
+
 enum ib_device_cap_flags {
 	IB_DEVICE_RESIZE_MAX_WR		= 1,
 	IB_DEVICE_BAD_PKEY_CNTR		= (1<<1),
@@ -1010,6 +1016,8 @@ struct ib_device {
 	int		           (*query_port)(struct ib_device *device,
 						 u8 port_num,
 						 struct ib_port_attr *port_attr);
+	enum rdma_link_layer	   (*get_link_layer)(struct ib_device *device,
+						     u8 port_num);
 	int		           (*query_gid)(struct ib_device *device,
 						u8 port_num, int index,
 						union ib_gid *gid);
@@ -1222,6 +1230,9 @@ int ib_query_device(struct ib_device *device,
 int ib_query_port(struct ib_device *device,
 		  u8 port_num, struct ib_port_attr *port_attr);
 
+enum rdma_link_layer rdma_port_get_link_layer(struct ib_device *device,
+					       u8 port_num);
+
 int ib_query_gid(struct ib_device *device,
 		 u8 port_num, int index, union ib_gid *gid);