Documentation/userspace-api/media/mediactl/media-request-ioc-reinit.rst

Source file repositories/reference/linux-study-clean/Documentation/userspace-api/media/mediactl/media-request-ioc-reinit.rst

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Linux kernel
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Documentation/userspace-api/media/mediactl/media-request-ioc-reinit.rst
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.rst
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1291 bytes
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Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
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atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Annotated Snippet

.. SPDX-License-Identifier: GPL-2.0 OR GFDL-1.1-no-invariants-or-later
.. c:namespace:: MC

.. _media_request_ioc_reinit:

******************************
ioctl MEDIA_REQUEST_IOC_REINIT
******************************

Name
====

MEDIA_REQUEST_IOC_REINIT - Re-initialize a request

Synopsis
========

.. c:macro:: MEDIA_REQUEST_IOC_REINIT

``int ioctl(int request_fd, MEDIA_REQUEST_IOC_REINIT)``

Arguments
=========

``request_fd``
    File descriptor returned by :ref:`MEDIA_IOC_REQUEST_ALLOC`.

Description
===========

If the media device supports :ref:`requests <media-request-api>`, then
this request ioctl can be used to re-initialize a previously allocated
request.

Re-initializing a request will clear any existing data from the request.
This avoids having to :c:func:`close()` a completed
request and allocate a new request. Instead the completed request can just
be re-initialized and it is ready to be used again.

A request can only be re-initialized if it either has not been queued
yet, or if it was queued and completed. Otherwise it will set ``errno``
to ``EBUSY``. No other error codes can be returned.

Return Value
============

On success 0 is returned, on error -1 and the ``errno`` variable is set
appropriately.

EBUSY
    The request is queued but not yet completed.

Annotation

Implementation Notes