Struct RdmaQueuePair

pub struct RdmaQueuePair {
    pub send_cq: usize,
    pub recv_cq: usize,
    pub qp: usize,
    pub dv_qp: usize,
    pub dv_send_cq: usize,
    pub dv_recv_cq: usize,
    pub send_wqe_idx: u32,
    pub send_db_idx: u32,
    pub send_cq_idx: u32,
    pub recv_wqe_idx: u32,
    pub recv_db_idx: u32,
    pub recv_cq_idx: u32,
    /* private fields */
}

Represents an RDMA Queue Pair (QP) that enables communication between two endpoints.

An RdmaQueuePair encapsulates the send and receive queues, completion queue, and other resources needed for RDMA communication. It provides methods for establishing connections and performing RDMA operations like read and write.

Fields

• send_cq - Send Completion Queue pointer for tracking send operation completions
• recv_cq - Receive Completion Queue pointer for tracking receive operation completions
• qp - Queue Pair pointer that manages send and receive operations
• dv_qp - Pointer to the mlx5 device-specific queue pair structure
• dv_send_cq - Pointer to the mlx5 device-specific send completion queue structure
• dv_recv_cq - Pointer to the mlx5 device-specific receive completion queue structure
• context - RDMA device context pointer
• config - Configuration settings for the queue pair

Connection Lifecycle

1. Create with new() from an RdmaDomain
2. Get connection info with get_qp_info()
3. Exchange connection info with remote peer (application must handle this)
4. Connect to remote endpoint with connect()
5. Perform RDMA operations with put() or get()
6. Poll for completions with poll_send_completion() or poll_recv_completion()

Fields

send_cq: usize

recv_cq: usize

qp: usize

dv_qp: usize

dv_send_cq: usize

dv_recv_cq: usize

send_wqe_idx: u32

send_db_idx: u32

send_cq_idx: u32

recv_wqe_idx: u32

recv_db_idx: u32

recv_cq_idx: u32

Implementations

impl RdmaQueuePair

pub fn new( context: *mut ibv_context, pd: *mut ibv_pd, config: IbverbsConfig, ) -> Result<Self, Error>

Creates a new RdmaQueuePair from a given RdmaDomain.

This function initializes a new Queue Pair (QP) and associated Completion Queue (CQ) using the resources from the provided RdmaDomain. The QP is created in the RESET state and must be transitioned to other states via the connect() method before use.

Arguments

• domain - Reference to an RdmaDomain that provides the context, protection domain, and memory region for this queue pair

Returns

• Result<Self> - A new RdmaQueuePair instance or an error if creation fails

Errors

This function may return errors if:

• Completion queue (CQ) creation fails
• Queue pair (QP) creation fails

pub fn get_qp_info(&mut self) -> Result<RdmaQpInfo, Error>

Returns the information required for a remote peer to connect to this queue pair.

This method retrieves the local queue pair attributes and port information needed by a remote peer to establish an RDMA connection. The returned RdmaQpInfo contains the queue pair number, LID, GID, and other necessary connection parameters.

Returns

• Result<RdmaQpInfo> - Connection information for the remote peer or an error

Errors

This function may return errors if:

• Port attribute query fails
• GID query fails

pub fn state(&mut self) -> Result<u32, Error>

pub fn connect(&mut self, connection_info: &RdmaQpInfo) -> Result<(), Error>

Connect to a remote Rdma connection point.

This performs the necessary QP state transitions (INIT->RTR->RTS) to establish a connection.

Arguments

• connection_info - The remote connection info to connect to

pub fn recv( &mut self, lhandle: RdmaBuffer, rhandle: RdmaBuffer, ) -> Result<(), Error>

pub fn put_with_recv( &mut self, lhandle: RdmaBuffer, rhandle: RdmaBuffer, ) -> Result<(), Error>

pub fn put( &mut self, lhandle: RdmaBuffer, rhandle: RdmaBuffer, ) -> Result<(), Error>

pub fn ring_doorbell(&mut self) -> Result<(), Error>

Get a doorbell for the queue pair.

This method returns a doorbell that can be used to trigger the execution of previously enqueued operations.

Returns

• Result<DoorBell, anyhow::Error> - A doorbell for the queue pair

pub fn enqueue_put( &mut self, lhandle: RdmaBuffer, rhandle: RdmaBuffer, ) -> Result<(), Error>

Enqueues a put operation without ringing the doorbell.

This method prepares a put operation but does not execute it. Use get_doorbell().ring() to execute the operation.

Arguments

• lhandle - Local buffer handle
• rhandle - Remote buffer handle

Returns

• Result<(), anyhow::Error> - Success or error

pub fn enqueue_put_with_recv( &mut self, lhandle: RdmaBuffer, rhandle: RdmaBuffer, ) -> Result<(), Error>

Enqueues a put with receive operation without ringing the doorbell.

This method prepares a put with receive operation but does not execute it. Use get_doorbell().ring() to execute the operation.

Arguments

• lhandle - Local buffer handle
• rhandle - Remote buffer handle

Returns

• Result<(), anyhow::Error> - Success or error

pub fn enqueue_get( &mut self, lhandle: RdmaBuffer, rhandle: RdmaBuffer, ) -> Result<(), Error>

Enqueues a get operation without ringing the doorbell.

This method prepares a get operation but does not execute it. Use get_doorbell().ring() to execute the operation.

Arguments

• lhandle - Local buffer handle
• rhandle - Remote buffer handle

Returns

• Result<(), anyhow::Error> - Success or error

pub fn get( &mut self, lhandle: RdmaBuffer, rhandle: RdmaBuffer, ) -> Result<(), Error>

pub fn poll_completion_target( &mut self, target: PollTarget, ) -> Result<Option<IbvWc>, Error>

Poll for completions on the specified completion queue(s)

Arguments

• target - Which completion queue(s) to poll (Send, Receive, or Both)

Returns

• Ok(Some(wc)) - A completion was found
• Ok(None) - No completion was found
• Err(e) - An error occurred

pub fn poll_send_completion(&mut self) -> Result<Option<IbvWc>, Error>

pub fn poll_recv_completion(&mut self) -> Result<Option<IbvWc>, Error>

Trait Implementations

impl Clone for RdmaQueuePair

fn clone(&self) -> RdmaQueuePair

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RdmaQueuePair

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for RdmaQueuePair

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Named for RdmaQueuePair

fn typename() -> &'static str

The globally unique type name for the type. This should typically be the fully qualified Rust name of the type.

fn typehash() -> u64

A globally unique hash for this type. TODO: actually enforce perfect hashing

fn typeid() -> TypeId

The TypeId for this type. TypeIds are unique only within a binary, and should not be used for global identification.

fn port() -> u64

The globally unique port for this type. Typed ports are in the range of 1<<63..1<<64-1.

fn arm(&self) -> Option<&'static str>

If the named type is an enum, this returns the name of the arm of the value self.

unsafe fn arm_unchecked(self_: *const ()) -> Option<&'static str>

An unsafe version of ‘arm’, accepting a pointer to the value, for use in type-erased settings.

impl Serialize for RdmaQueuePair

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.