dat_rmr_bind man page on OpenIndiana

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dat_rmr_bind(3DAT) Direct Access Transport Library Functionsdat_rmr_bind(3DAT)

NAME
dat_rmr_bind - bind the RMR to the specified memory region within an
LMR

SYNOPSIS
cc [ flag... ] file... -ldat [ library... ]
#include <dat/udat.h>

DAT_RETURN
dat_rmr_bind(
IN DAT_RMR_HANDLE rmr_handle,
IN DAT_LMR_TRIPLET *lmr_triplet,
IN DAT_MEM_PRIV_FLAGS mem_privileges,
IN DAT_EP_HANDLE ep_handle,
IN DAT_RMR_COOKIE user_cookie,
IN DAT_COMPLETION_FLAGS completion_flags,
OUT DAT_RMR_CONTEXT *rmr_context
)

PARAMETERS
rmr_handle Handle for an RMR instance.

lmr_triplet A pointer to an lmr_triplet that defines the memory
region of the LMR.

mem_privileges Consumer-requested memory access privileges for the
registered remote memory region. The Default value
is DAT_MEM_PRIV_NONE_FLAG. The constant value
DAT_MEM_PRIV_ALL_FLAG = 0x33, which specifies both
Read and Write privileges, is also defined. Memory
privilege definitions are as follows:

Remote Read DAT_MEM_PRIV_REMOTE_READ_FLAG

0x02 Remote read access
requested.

Remote Write DAT_MEM_PRIV_REMOTE_WRITE_FLAG

0x20 Remote write access
requested.

ep_handle Endpoint to which dat_rmr_bind() is posted.

user_cookie User-provided cookie that is returned to a Consumer
at the completion of the dat_rmr_bind(). Can be
NULL.

completion_flags Flags for RMR Bind. The default DAT_COMPLE‐
TION_DEFAULT_FLAG is 0. Flag definitions are as
follows:

Completion Suppression DAT_COMPLETION_SUP‐
PRESS_FLAG

0x01 Suppress suc‐
cessful Com‐
pletion.

Notification of Completion DAT_COMPLE‐
TION_UNSIGNALLED_FLAG

0x04 Non-notifica‐
tion comple‐
tion. Local
Endpoint must
be configured
for Notifica‐
tion Suppres‐
sion.

Barrier Fence DAT_COMPLETION_BAR‐
RIER_FENCE_FLAG

0x08 Request for
Barrier
Fence.

rmr_context New rmr_context for the bound RMR suitable to be
shared with a remote host.

DESCRIPTION
The dat_rmr_bind() function binds the RMR to the specified memory
region within an LMR and provides the new rmr_context value. The
dat_rmr_bind() operation is a lightweight asynchronous operation that
generates a new rmr_context. The Consumer is notified of the completion
of this operation through a rmr_bind Completion event on the
request_evd_handle of the specified Endpoint ep_handle.

The return value of rmr_context can be transferred by local Consumer to
a Consumer on a remote host to be used for an RDMA DTO. The use of
rmr_context by a remote host for an RDMA DTO prior to the completion of
the dat_rmr_bind() can result in an error and a broken connection. The
local Consumer can ensure that the remote Consumer does not have
rmr_context before dat_rmr_bind() is completed. One way is to "wait"
for the completion dat_rmr_bind() on the rmr_bind Event Dispatcher of
the specified Endpoint ep_handle. Another way is to send rmr_context in
a Send DTO over the connection of the Endpoint ep_handle. The barrier-
fencing behavior of the dat_rmr_bind() with respect to Send and RDMA
DTOs ensures that a Send DTO does not start until dat_rmr_bind() com‐
pleted.

The dat_rmr_bind() function automatically fences all Send, RDMA Read,
and RDMA Write DTOs and dat_rmr_bind() operations submitted on the End‐
point ep_handle after the dat_rmr_bind(). Therefore, none of these
operations starts until dat_rmr_bind() is completed.

If the RMR Bind fails after dat_rmr_bind() returns, connection of
ep_handle is broken. The Endpoint transitions into a DAT_EP_STATE_DIS‐
CONNECTED state and the DAT_CONNECTION_EVENT_BROKEN event is delivered
to the connect_evd_handle of the Endpoint.

The dat_rmr_bind() function employs fencing to ensure that operations
sending the RMR Context on the same Endpoint as the bind specified can‐
not result in an error from the peer side using the delivered RMR Con‐
text too soon. One method, used by InfiniBand, is to ensure that none
of these operations start on the Endpoint until after the bind is com‐
pleted. Other transports can employ different methods to achieve the
same goal.

Any RDMA DTO that uses the previous value of rmr_context after the
dat_rmr_bind() is completed fail and report a protection violation.

By default, dat_rmr_bind() generates notification completions.

The mem_privileges parameter allows Consumers to restrict the type of
remote accesses to the registered RMR by RDMA DTOs. Providers whose
underlying Transports require that privileges of the requested RMR and
the associated LMR match, that is

o Set RMR's DAT_MEM_PRIV_REMOTE_READ_FLAG requires that LMR's
DAT_MEM_PRIV_LOCAL_READ_FLAG is also set,

o Set RMR's DAT_MEM_PRIV_REMOTE_WRITE_FLAG requires that LMR's
DAT_MEM_PRIV_LOCAL_WRITE_FLAG is also set,

or the operation fails and returns DAT_PRIVILEGES_VIOLATION.

In the lmr_triplet, the value of length of zero means that the Consumer
does not want to associate an RMR with any memory region within the LMR
and the return value of rmr_context for that case is undefined.

The completion of the posted RMR Bind is reported to the Consumer asyn‐
chronously through a DTO Completion event based on the specified com‐
pletion_flags value. The value of DAT_COMPLETION_UNSIGNALLED_FLAG is
only valid if the Endpoint Request Completion Flags DAT_COMPLE‐
TION_UNSIGNALLED_FLAG. Otherwise, DAT_INVALID_PARAMETER is returned.

The user_cookie parameter allows Consumers to have unique identifiers
for each dat_rmr_bind(). These identifiers are completely under user
control and are opaque to the Provider. The Consumer is not required to
ensure the uniqueness of the user_cookie value. The user_cookie is
returned to the Consumer in the rmr_bind Completion event for this
operation.

The operation is valid for the Endpoint in the DAT_EP_STATE_CONNECTED
and DAT_EP_STATE_DISCONNECTED states. If the operation returns success‐
fully for the Endpoint in DAT_EP_STATE_DISCONNECTED state, the posted
RMR Bind is immediately flushed to request_evd_handle.

RETURN VALUES
DAT_SUCCESS The operation was successful.

DAT_INSUFFICIENT_RESOURCES The operation failed due to resource lim‐
itations.

DAT_INVALID_PARAMETER Invalid parameter. For example, the tar‐
get_address or segment_length exceeded
the limits of the existing LMR.

DAT_INVALID_HANDLE Invalid DAT handle.

DAT_INVALID_STATE Parameter in an invalid state. Endpoint
was not in the a DAT_EP_STATE_CONNECTED
or DAT_EP_STATE_DISCONNECTED state.

DAT_MODEL_NOT_SUPPORTED The requested Model was not supported by
the Provider.

DAT_PRIVILEGES_VIOLATION Privileges violation for local or remote
memory access.

DAT_PROTECTION_VIOLATION Protection violation for local or remote
memory access.

ATTRIBUTES
See attributes(5) for descriptions of the following attributes:

┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │Unsafe │
├─────────────────────────────┼─────────────────────────────┤
│Standard │uDAPL, 1.1, 1.2 │
└─────────────────────────────┴─────────────────────────────┘