man/man3rsm/rsm_memseg_import_putv.3rsm

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 RSM_MEMSEG_IMPORT_PUTV 3RSM "Nov 12, 2001"
 NAME
rsm_memseg_import_putv, rsm_memseg_import_getv - write to a segment using a
list of I/O requests
 SYNOPSIS

cc [ flag... ] file... -lrsm [ library... ]
#include <rsmapi.h>

int rsm_memseg_import_putv(rsm_scat_gath_t *sg_io);


int rsm_memseg_import_getv(rsm_scat_gath_t *sg_io);


 DESCRIPTION

The rsm_memseg_import_putv() and rsm_memseg_import_getv() functions
provide for using a list of I/O requests rather than a single source and
destination address as is done for thersm_memseg_import_put(3RSM) and
rsm_memseg_import_get(3RSM) functions.

The I/O vector component of the scatter-gather list (sg_io), allows
specifying local virtual addresses or local_memory_handles. When a local
address range is used repeatedly, it is efficient to use a handle because
allocated system resources (that is, locked down local memory) are maintained
until the handle is freed. The supporting functions for handles are
rsm_create_localmemory_handle(3RSM) and
rsm_free_localmemory_handle(3RSM).

Virtual addresses or handles may be gathered into the vector for writing to a
single remote segment, or a read from a single remote segment may be scattered
to the vector of virtual addresses or handles.

Implicit mapping is supported for the scatter-gather type of access. The
attributes of the extension library for the specific interconnect are used to
determine whether mapping is necessary before any scatter-gather access. If
mapping of the imported segment is a prerequisite for scatter-gather access and
the mapping has not already been performed, an implicit mapping is performed
for the imported segment. The I/O for the vector is then initiated.

I/O for the entire vector is initiated before returning. The barrier mode
attribute of the import segment determines if the I/O has completed before the
function returns. A barrier mode attribute setting of IMPLICIT
guarantees that the transfer of data is completed in the order as entered in
the I/O vector. An implicit barrier open and close surrounds each list entry.
If an error is detected, I/O for the vector is terminated and the function
returns immediately. The residual count indicates the number of entries for
which the I/O either did not complete or was not initiated.

The number of entries in the I/O vector component of the scatter-gather list is
specified in the io_request_count field of the rsm_scat_gath_t
pointed to by sg_io. The io_request_count is valid if greater than
0 and less than or equal to RSM_MAX_SGIOREQS. If io_request_count
is not in the valid range, rsm_memseg_import_putv() and
rsm_memseg_import_getv() returns RSMERR_BAD_SGIO.

Optionally, the scatter-gather list allows support for an implicit signal post
after the I/O for the entire vector has completed. This alleviates the need to
do an explicit signal post after ever I/O transfer operation. The means of
enabling the implicit signal post involves setting the flags field within
the scatter-gather list to RSM_IMPLICIT_SIGPOST. The flags field
may also be set to RSM_SIG_POST_NO_ACCUMULATE, which will be passed on to
the signal post operation when RSM_IMPLICIT_SIGPOST is set.
 RETURN VALUES

Upon successful completion, these functions return 0. Otherwise, an error value
is returned to indicate the error.
 ERRORS

The rsm_memseg_import_putv() and rsm_memseg_import_getv() functions
can return the following errors:
RSMERR_BAD_SGIO

Invalid scatter-gather structure pointer.


RSMERR_BAD_SEG_HNDL

Invalid segment handle.


RSMERR_BAD_CTLR_HNDL

Invalid controller handle.


RSMERR_BAD_OFFSET

Invalid offset.


RSMERR_BAD_LENGTH

Invalid length.


RSMERR_BAD_ADDR

Bad address.


RSMERR_INSUFFICIENT_RESOURCES

Insufficient resources.


RSMERR_INTERRUPTED

The operation was interrupted by a signal.


RSMERR_PERM_DENIED

Permission denied.


RSMERR_BARRIER_FAILURE

I/O completion error.


RSMERR_REMOTE_NODE_UNREACHABLE

Remote node not reachable.


 ATTRIBUTES

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


ATTRIBUTE TYPE ATTRIBUTE VALUE
Interface Stability Evolving
MT-Level MT-Safe


 SEE ALSO

rsm_create_localmemory_handle(3RSM),
rsm_free_localmemory_handle(3RSM), attributes(5)