.\" Automatically generated by Pandoc 3.6
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.TH "mlx5dv_devx_umem_export / mlx5dv_devx_umem_import / mlx5dv_devx_umem_unimport" "3" "" ""
.SH NAME
mlx5dv_devx_umem_export \- Export DEVX UMEM attributes for
cross\-process sharing
.PP
mlx5dv_devx_umem_import \- Import a DEVX UMEM from exported attributes
.PP
mlx5dv_devx_umem_unimport \- Unimport a DEVX UMEM
.SH SYNOPSIS
.IP
.EX
#include \f[B]<infiniband/mlx5dv.h>\f[R]

int mlx5dv_devx_umem_export(\f[B]struct\f[R] mlx5dv_devx_umem *umem, void *data);

\f[B]struct\f[R] mlx5dv_devx_umem *
mlx5dv_devx_umem_import(\f[B]struct\f[R] ibv_context *context, void *data);

void mlx5dv_devx_umem_unimport(\f[B]struct\f[R] mlx5dv_devx_umem *umem);
.EE
.SH DESCRIPTION
These functions enable cross\-process sharing of DEVX UMEM objects.
.PP
\f[I]mlx5dv_devx_umem_export()\f[R] exports DEVX UMEM attributes into a
data buffer.
The buffer must be allocated by the caller with at least the size
returned by \f[I]mlx5dv_get_export_sizes()\f[R] in the
\f[I]devx_umem_attrs_size\f[R] field.
.PP
\f[I]mlx5dv_devx_umem_import()\f[R] returns a DEVX UMEM that is
associated with the exported attributes in the given \f[I]context\f[R].
The \f[I]data\f[R] buffer must have been previously filled by
\f[I]mlx5dv_devx_umem_export()\f[R].
.PP
The \f[I]context\f[R] can be the original UMEM registering context or
any context sharing the same kernel resources (e.g., via
\f[I]ibv_import_device()\f[R]).
.PP
\f[I]mlx5dv_devx_umem_unimport()\f[R] unimports a DEVX UMEM that was
imported via \f[I]mlx5dv_devx_umem_import()\f[R].
Once the UMEM usage has ended, either \f[I]mlx5dv_devx_umem_dereg()\f[R]
or \f[I]mlx5dv_devx_umem_unimport()\f[R] should be called.
\f[I]mlx5dv_devx_umem_dereg()\f[R] deregisters the kernel object, while
\f[I]mlx5dv_devx_umem_unimport()\f[R] only cleans up local resources
without affecting the kernel object.
.PP
It is the responsibility of the application to coordinate between all
contexts that use this UMEM.
Once deregistration is done, no other process can use the object except
for unimport.
All users must collaborate to ensure this.
.SH ARGUMENTS
.SS mlx5dv_devx_umem_export
.TP
\f[I]umem\f[R]
The DEVX UMEM to export.
.TP
\f[I]data\f[R]
Pointer to a buffer to be filled with the exported attributes.
The buffer must be at least \f[I]devx_umem_attrs_size\f[R] bytes as
returned by \f[I]mlx5dv_get_export_sizes()\f[R].
.SS mlx5dv_devx_umem_import
.TP
\f[I]context\f[R]
RDMA device context to import the DEVX UMEM into.
.TP
\f[I]data\f[R]
Pointer to a buffer previously filled by
\f[I]mlx5dv_devx_umem_export()\f[R].
.SH RETURN VALUE
\f[I]mlx5dv_devx_umem_export()\f[R] returns 0 on success, or the value
of errno on error.
.PP
\f[I]mlx5dv_devx_umem_import()\f[R] returns a pointer to a \f[I]struct
mlx5dv_devx_umem\f[R] on success, or NULL on error with errno set.
.SH SEE ALSO
\f[B]mlx5dv_devx_umem_reg\f[R], \f[B]mlx5dv_get_export_sizes\f[R],
\f[B]mlx5dv_open_device\f[R]
.SH AUTHOR
Maher Sanalla \c
.MT msanalla@nvidia.com
.ME \c