86 lines
4.1 KiB
Groff
86 lines
4.1 KiB
Groff
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.TH "RDMA_ACCEPT" 3 "2007-10-31" "librdmacm" "Librdmacm Programmer's Manual" librdmacm
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.SH NAME
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rdma_accept \- Called to accept a connection request.
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.SH SYNOPSIS
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.B "#include <rdma/rdma_cma.h>"
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.P
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.B "int" rdma_accept
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.BI "(struct rdma_cm_id *" id ","
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.BI "struct rdma_conn_param *" conn_param ");"
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.SH ARGUMENTS
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.IP "id" 12
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Connection identifier associated with the request.
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.IP "conn_param" 12
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Information needed to establish the connection. See CONNECTION PROPERTIES
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below for details.
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.SH "DESCRIPTION"
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Called from the listening side to accept a connection or datagram
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service lookup request.
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.SH "NOTES"
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Unlike the socket accept routine, rdma_accept is not called on a
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listening rdma_cm_id. Instead, after calling rdma_listen, the user
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waits for an RDMA_CM_EVENT_CONNECT_REQUEST event to occur. Connection request
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events give the user a newly created rdma_cm_id, similar to a new
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socket, but the rdma_cm_id is bound to a specific RDMA device.
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rdma_accept is called on the new rdma_cm_id.
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.SH "CONNECTION PROPERTIES"
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The following properties are used to configure the communication and specified
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by the conn_param parameter when accepting a connection or datagram
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communication request. Users should use the rdma_conn_param values reported
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in the connection request event to determine appropriate values for these
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fields when accepting. Users may reference the rdma_conn_param structure in
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the connection event directly, or can reference their own structure. If the
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rdma_conn_param structure from an event is referenced, the event must not be
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acked until after this call returns.
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.IP private_data
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References a user-controlled data buffer. The contents of the buffer are
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copied and transparently passed to the remote side as part of the
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communication request. May be NULL if private_data is not required.
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.IP private_data_len
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Specifies the size of the user-controlled data buffer. Note that the actual
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amount of data transferred to the remote side is transport dependent and may
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be larger than that requested.
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.IP responder_resources
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The maximum number of outstanding RDMA read and atomic operations that the
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local side will accept from the remote side. Applies only to RDMA_PS_TCP.
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This value must be less than or equal to the local RDMA device attribute
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max_qp_rd_atom and the responder_resources value reported in the connect
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request event.
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.IP initiator_depth
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The maximum number of outstanding RDMA read and atomic operations that the
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local side will have to the remote side. Applies only to RDMA_PS_TCP.
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This value must be less than or equal to the local RDMA device attribute
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max_qp_init_rd_atom and the initiator_depth value reported in the connect
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request event.
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.IP flow_control
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Specifies if hardware flow control is available. This value is exchanged
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with the remote peer and is not used to configure the QP. Applies only to
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RDMA_PS_TCP.
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.IP retry_count
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This value is ignored.
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.IP rnr_retry_count
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The maximum number of times that a send operation from the remote peer
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should be retried on a connection after receiving a receiver not ready (RNR)
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error. RNR errors are generated when a send request arrives before a buffer
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has been posted to receive the incoming data. Applies only to RDMA_PS_TCP.
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.IP srq
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Specifies if the QP associated with the connection is using a shared receive
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queue. This field is ignored by the library if a QP has been created on the
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rdma_cm_id. Applies only to RDMA_PS_TCP.
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.IP qp_num
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Specifies the QP number associated with the connection. This field is ignored
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by the library if a QP has been created on the rdma_cm_id.
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.SH "INFINIBAND SPECIFIC"
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In addition to the connection properties defined above, InfiniBand QPs are
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configured with minimum RNR NAK timer and local ACK timeout values. The
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minimum RNR NAK timer value is set to 0, for a delay of 655 ms.
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The local ACK timeout is calculated based on the packet lifetime and local
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HCA ACK delay. The packet lifetime is determined by the InfiniBand Subnet
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Administrator and is part of the route (path record) information obtained
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by the active side of the connection. The HCA ACK delay is a property of
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the locally used HCA.
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.P
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The RNR retry count is a 3-bit value.
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.SH "SEE ALSO"
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rdma_listen(3), rdma_reject(3), rdma_get_cm_event(3)
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