path: root/usr/src/man/man3dat/dat_ep_post_rdma_write.3dat

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.TH DAT_EP_POST_RDMA_WRITE 3DAT "Jul 16, 2004"
.SH NAME
dat_ep_post_rdma_write \- write all data to the remote data buffer
.SH SYNOPSIS
.LP
.nf
cc [ \fIflag\fR\&.\|.\|. ] \fIfile\fR\&.\|.\|. \fB-ldat\fR [ \fIlibrary\fR\&.\|.\|. ]
#include <\fBdat/udat.h\fR>

DAT_RETURN
    dat_ep_post_rdma_read (
    IN    DAT_EP_HANDLE        ep_handle,
    IN    DAT_COUNT            num_segments,
    IN    DAT_LMR_TRIPLET      *local_iov,
    IN    DAT_DTO_COOKIE       user_cookie,
    IN    DAT_RMR_TRIPLET      *remote_buffer,
    IN    DAT_COMPLETION_FLAGS completion_flags
    )
.fi

.SH PARAMETERS
.sp
.ne 2
.na
\fB\fIep_handle\fR\fR
.ad
.RS 20n
Handle for an instance of the Endpoint.
.RE

.sp
.ne 2
.na
\fB\fInum_segments\fR\fR
.ad
.RS 20n
Number of \fIlmr_triplets\fR in \fIlocal_iov\fR.
.RE

.sp
.ne 2
.na
\fB\fIlocal_iov\fR\fR
.ad
.RS 20n
I/O Vector that specifies the local buffer from which the data is transferred.
.RE

.sp
.ne 2
.na
\fB\fIuser_cookie\fR\fR
.ad
.RS 20n
User-provided cookie that is returned to the Consumer at the completion of the
RDMA Write.
.RE

.sp
.ne 2
.na
\fB\fIremote_buffer\fR\fR
.ad
.RS 20n
A pointer to an RMR Triplet that specifies the remote buffer from which the
data is read.
.RE

.sp
.ne 2
.na
\fB\fIcompletion_flags\fR\fR
.ad
.RS 20n
Flags for posted RDMA read. The default \fBDAT_COMPLETION_DEFAULT_FLAG\fR is
0x00. Other values are as follows:
.sp
.ne 2
.na
\fBCompletion Suppression\fR
.ad
.RS 30n
\fBDAT_COMPLETION_SUPPRESS_FLAG\fR
.sp
.ne 2
.na
\fB0x01\fR
.ad
.RS 8n
Suppress successful Completion.
.RE

.RE

.sp
.ne 2
.na
\fBNotification of Completion\fR
.ad
.RS 30n
\fB\fR\fBDAT_COMPLETION_UNSIGNALLED_FLAG\fR
.sp
.ne 2
.na
\fB0x04\fR
.ad
.RS 8n
Non-notification completion. Local Endpoint must be configured for Notification
Suppression.
.RE

.RE

.sp
.ne 2
.na
\fBBarrier Fence\fR
.ad
.RS 30n
\fB\fR\fBDAT_COMPLETION_BARRIER_FENCE_FLAG\fR
.sp
.ne 2
.na
\fB0x08\fR
.ad
.RS 8n
Request for Barrier Fence.
.RE

.RE

.RE

.SH DESCRIPTION
.sp
.LP
The \fBdat_ep_post_rdma_write()\fR function requests the transfer of all the
data specified by the \fIlocal_iov\fR over the connection of the
\fIep_handle\fR Endpoint into the \fIremote_buffer\fR.
.sp
.LP
The \fInum_segments\fR parameter specifies the number of segments in the
\fIlocal_iov\fR. The \fIlocal_iov\fR segments are traversed in the I/O Vector
order until all the data is transferred.
.sp
.LP
A Consumer must not modify the \fIlocal_iov\fR or its content until the DTO is
completed. When a Consumer does not adhere to this rule, the behavior of the
Provider and the underlying Transport is not defined. Providers that allow
Consumers to get ownership of the \fIlocal_iov\fR but not the memory it
specifies back after the \fBdat_ep_post_rdma_write()\fR returns should document
this behavior and also specify its support in Provider attributes. This
behavior allows Consumers full control of the \fIlocal_iov\fR after
\fBdat_ep_post_rdma_write()\fR returns. Because this behavior is not guaranteed
by all Providers, portable Consumers should not rely on this behavior.
Consumers should not rely on the Provider copying \fIlocal_iov\fR information.
.sp
.LP
The \fBDAT_SUCCESS\fR return of the \fBdat_ep_post_rdma_write()\fR is at least
the equivalent of posting an RDMA Write operation directly by native Transport.
Providers should avoid resource allocation as part of
\fBdat_ep_post_rdma_write()\fR to ensure that this operation is nonblocking and
thread safe for an UpCall.
.sp
.LP
The completion of the posted RDMA Write is reported to the Consumer
asynchronously through a DTO Completion event based on the specified
\fIcompletion_flags\fR value. The value of
\fBDAT_COMPLETION_UNSIGNALLED_FLAG\fR is only valid if the Endpoint Request
Completion Flags \fBDAT_COMPLETION_UNSIGNALLED_FLAG\fR. Otherwise,
\fBDAT_INVALID_PARAMETER\fR is returned.
.sp
.LP
The \fIuser_cookie\fR allows Consumers to have unique identifiers for each DTO.
These identifiers are completely under user control and are opaque to the
Provider. There is no requirement on the Consumer that the value
\fIuser_cookie\fR should be unique for each DTO. The \fIuser_cookie\fR is
returned to the Consumer in the Completion event for the posted RDMA Write.
.sp
.LP
The operation is valid for the Endpoint in the \fBDAT_EP_STATE_CONNECTED\fR and
\fBDAT_EP_STATE_DISCONNECTED\fR states. If the operation returns successfully
for the Endpoint in the \fBDAT_EP_STATE_DISCONNECTED\fR state, the posted RDMA
Write is immediately flushed to \fIrequest_evd_handle\fR.
.SH RETURN VALUES
.sp
.ne 2
.na
\fB\fBDAT_SUCCESS\fR\fR
.ad
.RS 30n
The operation was successful.
.RE

.sp
.ne 2
.na
\fB\fBDAT_INSUFFICIENT_RESOURCES\fR\fR
.ad
.RS 30n
The operation failed due to resource limitations.
.RE

.sp
.ne 2
.na
\fB\fBDAT_INVALID_PARAMETER\fR\fR
.ad
.RS 30n
Invalid parameter. For example, one of the IOV segments pointed to a memory
outside its LMR.
.RE

.sp
.ne 2
.na
\fB\fBDAT_INVALID_HANDLE\fR\fR
.ad
.RS 30n
The \fIep_handle\fR parameter is invalid.
.RE

.sp
.ne 2
.na
\fB\fBDAT_INVALID_STATE\fR\fR
.ad
.RS 30n
A parameter is in an invalid state. Endpoint was not in the
\fBDAT_EP_STATE_CONNECTED\fR or \fBDAT_EP_STATE_DISCONNECTED\fR state.
.RE

.sp
.ne 2
.na
\fB\fBDAT_LENGTH_ERROR\fR\fR
.ad
.RS 30n
The size of the receiving buffer is too small for sending buffer data. The size
of the remote buffer is too small for the data of the local buffer.
.RE

.sp
.ne 2
.na
\fB\fBDAT_PROTECTION_VIOLATION\fR\fR
.ad
.RS 30n
Protection violation for local or remote memory access. Protection Zone
mismatch between either an LMR of one of the \fIlocal_iov\fR segments and the
local Endpoint or the \fIrmr_context\fR and the remote Endpoint.
.RE

.sp
.ne 2
.na
\fB\fBDAT_PRIVILEGES_VIOLATION\fR\fR
.ad
.RS 30n
Privileges violation for local or remote memory access. Either one of the LMRs
used in \fIlocal_iov\fR is invalid or does not have the local read privileges,
or \fIrmr_context\fR does not have the remote write privileges.
.RE

.SH USAGE
.sp
.LP
For best RDMA Write operation performance, the Consumer should align each
buffer segment of \fIlocal_iov\fR to the Optimal Buffer Alignment attribute of
the Provider. For portable applications, the Consumer should align each buffer
segment of \fIlocal_iov\fR to the \fBDAT_OPTIMAL_ALIGNMENT\fR.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard: uDAPL, 1.1, 1.2
_
MT-Level	Unsafe
.TE

.SH SEE ALSO
.sp
.LP
.BR libdat (3LIB),
.BR attributes (7)