rdmacreateid

rdmacreateid is not a formal function name in the RDMA libraries; it is a commonly used informal reference to the rdma_create_id function in the librdmacm API, which is part of the RDMA Connection Manager. The function creates a new RDMA communication identifier (rdma_cm_id), which serves as the program’s representation of a communication endpoint for RDMA operations. The identifier is used to perform address resolution, route resolution, and to establish or accept connections through the RDMA CM.

The typical usage involves providing an event channel to receive asynchronous RDMA events related to this endpoint, a location to store the newly created rdma_cm_id, a user-defined context pointer, and a port space selector that indicates the transport type (for example RDMA_PS_TCP for IP-based TCP transports or RDMA_PS_IB for InfiniBand/IB verbs). On success, the call returns zero and sets the rdma_cm_id pointer; on failure, it returns a negative error value and sets errno.

After creation, the rdma_cm_id is used with a sequence of operations to set up communication. Common steps include binding a local address with rdma_bind_addr, resolving the local and remote addresses with rdma_resolve_addr, resolving the route with rdma_resolve_route, and then establishing a connection with rdma_connect for active connections or entering a listening state with rdma_listen and accepting connections via rdma_accept for passive connections. The rdma_cm_id provides access to the underlying queue pair and device context for subsequent RDMA verbs operations.

Resource management involves releasing the identifier when it is no longer needed, via rdma_destroy_id, and cleaning up the associated event channel with rdma_destroy_event_channel. The canonical API name is rdma_create_id, and “rdmacreateid” serves as a shorthand reference in many documentation sources.