Struct ibverbs::PreparedQueuePair

pub struct PreparedQueuePair<'res> { /* private fields */ }

An allocated but uninitialized QueuePair.

Specifically, this QueuePair has been allocated with ibv_create_qp, but has not yet been initialized with calls to ibv_modify_qp.

To complete the construction of the QueuePair, you will need to obtain the QueuePairEndpoint of the remote end (by using PreparedQueuePair::endpoint), and then call PreparedQueuePair::handshake on both sides with the other side’s QueuePairEndpoint:

// on host 1
let pqp: PreparedQueuePair = ...;
let host1end = pqp.endpoint();
host2.send(host1end);
let host2end = host2.recv();
let qp = pqp.handshake(host2end);

// on host 2
let pqp: PreparedQueuePair = ...;
let host2end = pqp.endpoint();
host1.send(host2end);
let host1end = host1.recv();
let qp = pqp.handshake(host1end);

Implementations

impl<'res> PreparedQueuePair<'res>

pub fn endpoint(&self) -> QueuePairEndpoint

Get the network endpoint for this QueuePair.

This endpoint will need to be communicated to the QueuePair on the remote end.

pub fn handshake(self, remote: QueuePairEndpoint) -> Result<QueuePair<'res>>

Set up the QueuePair such that it is ready to exchange packets with a remote QueuePair.

Internally, this uses ibv_modify_qp to mark the QueuePair as initialized (IBV_QPS_INIT), ready to receive (IBV_QPS_RTR), and ready to send (IBV_QPS_RTS). Further discussion of the protocol can be found on RDMAmojo.

If the endpoint contains a Gid, the routing will be global. This means:

ah_attr.is_global = 1;
ah_attr.grh.hop_limit = 0xff;

The handshake also sets the following parameters, which are currently not configurable:

Examples

port_num = PORT_NUM;
pkey_index = 0;
rq_psn = 0;
sq_psn = 0;

max_dest_rd_atomic = 1;
max_rd_atomic = 1;

ah_attr.sl = 0;
ah_attr.src_path_bits = 0;

Errors

• EINVAL: Invalid value provided in attr or in attr_mask.
• ENOMEM: Not enough resources to complete this operation.