RDMA/netlink: Advertise IB subnet prefix

Add IB subnet prefix to the port properties exported
by RDMA netlink.
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

drivers/infiniband/core/nldev.c

@@ -44,6 +44,7 @@ static const struct nla_policy nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 					    .len = IB_FW_VERSION_NAME_MAX - 1},
 	[RDMA_NLDEV_ATTR_NODE_GUID]	= { .type = NLA_U64 },
 	[RDMA_NLDEV_ATTR_SYS_IMAGE_GUID] = { .type = NLA_U64 },
+	[RDMA_NLDEV_ATTR_SUBNET_PREFIX]	= { .type = NLA_U64 },
 };
 
 static int fill_dev_info(struct sk_buff *msg, struct ib_device *device)
@@ -97,6 +98,10 @@ static int fill_port_info(struct sk_buff *msg,
 	if (nla_put_u64_64bit(msg, RDMA_NLDEV_ATTR_CAP_FLAGS,
 			      (u64)attr.port_cap_flags, 0))
 		return -EMSGSIZE;
+	if (rdma_protocol_ib(device, port) &&
+	    nla_put_u64_64bit(msg, RDMA_NLDEV_ATTR_SUBNET_PREFIX,
+			      attr.subnet_prefix, 0))
+		return -EMSGSIZE;
 
 	return 0;
 }

include/uapi/rdma/rdma_netlink.h

@@ -279,6 +279,11 @@ enum rdma_nldev_attr {
 	 */
 	RDMA_NLDEV_ATTR_SYS_IMAGE_GUID,		/* u64 */
 
+	/*
+	 * Subnet prefix (in host byte order)
+	 */
+	RDMA_NLDEV_ATTR_SUBNET_PREFIX,		/* u64 */
+
 	RDMA_NLDEV_ATTR_MAX
 };
 #endif /* _UAPI_RDMA_NETLINK_H */