RDMA/nldev: Return device protocol

Add new RDMA_NLDEV_ATTR_DEV_PROTOCOL attribute to give ability for UDEV
rules create IB device stable names based on link type protocol.  The
assumption that devices like mlx4 with duality in their link type under
one IB device struct won't be allowed in the future.
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/nldev.c

@@ -117,6 +117,8 @@ static const struct nla_policy nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 	[RDMA_NLDEV_ATTR_LINK_TYPE]		= { .type = NLA_NUL_STRING,
 				    .len = RDMA_NLDEV_ATTR_ENTRY_STRLEN },
 	[RDMA_NLDEV_SYS_ATTR_NETNS_MODE]	= { .type = NLA_U8 },
+	[RDMA_NLDEV_ATTR_DEV_PROTOCOL]		= { .type = NLA_NUL_STRING,
+				    .len = RDMA_NLDEV_ATTR_ENTRY_STRLEN },
 };
 
 static int put_driver_name_print_type(struct sk_buff *msg, const char *name,
@@ -199,6 +201,8 @@ static int fill_nldev_handle(struct sk_buff *msg, struct ib_device *device)
 static int fill_dev_info(struct sk_buff *msg, struct ib_device *device)
 {
 	char fw[IB_FW_VERSION_NAME_MAX];
+	int ret = 0;
+	u8 port;
 
 	if (fill_nldev_handle(msg, device))
 		return -EMSGSIZE;
@@ -227,7 +231,25 @@ static int fill_dev_info(struct sk_buff *msg, struct ib_device *device)
 		return -EMSGSIZE;
 	if (nla_put_u8(msg, RDMA_NLDEV_ATTR_DEV_NODE_TYPE, device->node_type))
 		return -EMSGSIZE;
-	return 0;
+
+	/*
+	 * Link type is determined on first port and mlx4 device
+	 * which can potentially have two different link type for the same
+	 * IB device is considered as better to be avoided in the future,
+	 */
+	port = rdma_start_port(device);
+	if (rdma_cap_opa_mad(device, port))
+		ret = nla_put_string(msg, RDMA_NLDEV_ATTR_DEV_PROTOCOL, "opa");
+	else if (rdma_protocol_ib(device, port))
+		ret = nla_put_string(msg, RDMA_NLDEV_ATTR_DEV_PROTOCOL, "ib");
+	else if (rdma_protocol_iwarp(device, port))
+		ret = nla_put_string(msg, RDMA_NLDEV_ATTR_DEV_PROTOCOL, "iw");
+	else if (rdma_protocol_roce(device, port))
+		ret = nla_put_string(msg, RDMA_NLDEV_ATTR_DEV_PROTOCOL, "roce");
+	else if (rdma_protocol_usnic(device, port))
+		ret = nla_put_string(msg, RDMA_NLDEV_ATTR_DEV_PROTOCOL,
+				     "usnic");
+	return ret;
 }
 
 static int fill_port_info(struct sk_buff *msg,

include/uapi/rdma/rdma_netlink.h

@@ -470,6 +470,11 @@ enum rdma_nldev_attr {
 	 */
 	RDMA_NLDEV_SYS_ATTR_NETNS_MODE,		/* u8 */
 
+	/*
+	 * Device protocol, e.g. ib, iw, usnic, roce and opa
+	 */
+	RDMA_NLDEV_ATTR_DEV_PROTOCOL,		/* string */
+
 	/*
 	 * Always the end
 	 */