вызывается для принятия запроса на подключение (Called to accept a connection request.)
Имя (Name)
rdma_accept - Called to accept a connection request.
Синопсис (Synopsis)
#include <rdma/rdma_cma.h>
int rdma_accept (struct rdma_cm_id *id, struct rdma_conn_param
*conn_param);
Аргументы (Arguments)
id Connection identifier associated with the request.
conn_param Information needed to establish the connection. See
CONNECTION PROPERTIES below for details.
Описание (Description)
Called from the listening side to accept a connection or datagram
service lookup request.
Возвращаемое значение (Return value)
Returns 0 on success, or -1 on error. If an error occurs, errno
will be set to indicate the failure reason.
Примечание (Note)
Unlike the socket accept routine, rdma_accept is not called on a
listening rdma_cm_id. Instead, after calling rdma_listen, the
user waits for an RDMA_CM_EVENT_CONNECT_REQUEST event to occur.
Connection request events give the user a newly created
rdma_cm_id, similar to a new socket, but the rdma_cm_id is bound
to a specific RDMA device. rdma_accept is called on the new
rdma_cm_id.
CONNECTION PROPERTIES
The following properties are used to configure the communication
and specified by the conn_param parameter when accepting a
connection or datagram communication request. Users should use
the rdma_conn_param values reported in the connection request
event to determine appropriate values for these fields when
accepting. Users may reference the rdma_conn_param structure in
the connection event directly, or can reference their own
structure. If the rdma_conn_param structure from an event is
referenced, the event must not be acked until after this call
returns.
If the conn_param parameter is NULL, the values reported in the
connection request event are used, adjusted down based on local
hardware restrictions.
private_data
References a user-controlled data buffer. The contents of
the buffer are copied and transparently passed to the
remote side as part of the communication request. May be
NULL if private_data is not required.
private_data_len
Specifies the size of the user-controlled data buffer.
Note that the actual amount of data transferred to the
remote side is transport dependent and may be larger than
that requested.
responder_resources
The maximum number of outstanding RDMA read and atomic
operations that the local side will accept from the remote
side. Applies only to RDMA_PS_TCP. This value must be
less than or equal to the local RDMA device attribute
max_qp_rd_atom, but preferably greater than or equal to
the responder_resources value reported in the connect
request event.
initiator_depth
The maximum number of outstanding RDMA read and atomic
operations that the local side will have to the remote
side. Applies only to RDMA_PS_TCP. This value must be
less than or equal to the local RDMA device attribute
max_qp_init_rd_atom and the initiator_depth value reported
in the connect request event.
flow_control
Specifies if hardware flow control is available. This
value is exchanged with the remote peer and is not used to
configure the QP. Applies only to RDMA_PS_TCP.
retry_count
This value is ignored.
rnr_retry_count
The maximum number of times that a send operation from the
remote peer should be retried on a connection after
receiving a receiver not ready (RNR) error. RNR errors
are generated when a send request arrives before a buffer
has been posted to receive the incoming data. Applies
only to RDMA_PS_TCP.
srq Specifies if the QP associated with the connection is
using a shared receive queue. This field is ignored by
the library if a QP has been created on the rdma_cm_id.
Applies only to RDMA_PS_TCP.
qp_num Specifies the QP number associated with the connection.
This field is ignored by the library if a QP has been
created on the rdma_cm_id.
Cпецифический InfiniBand (InfiniBand specific)
In addition to the connection properties defined above,
InfiniBand QPs are configured with minimum RNR NAK timer and
local ACK timeout values. The minimum RNR NAK timer value is set
to 0, for a delay of 655 ms. The local ACK timeout is calculated
based on the packet lifetime and local HCA ACK delay. The packet
lifetime is determined by the InfiniBand Subnet Administrator and
is part of the route (path record) information obtained by the
active side of the connection. The HCA ACK delay is a property
of the locally used HCA.
The RNR retry count is a 3-bit value.
The length of the private data provided by the user is limited to
196 bytes for RDMA_PS_TCP, or 136 bytes for RDMA_PS_UDP.
Смотри также (See also)
rdma_listen(3), rdma_reject(3), rdma_get_cm_event(3)
