..  SPDX-License-Identifier: BSD-3-Clause
    Copyright 2018 The DPDK contributors

ABI and API Deprecation
=======================

See the guidelines document for details of the :doc:`ABI policy
<../contributing/abi_policy>`. API and ABI deprecation notices are to be posted
here.

Deprecation Notices
-------------------

* kvargs: The function ``rte_kvargs_process`` will get a new parameter
  for returning key match count. It will ease handling of no-match case.

* eal: The function ``rte_eal_remote_launch`` will return new error codes
  after read or write error on the pipe, instead of calling ``rte_panic``.

* rte_atomicNN_xxx: These APIs do not take memory order parameter. This does
  not allow for writing optimized code for all the CPU architectures supported
  in DPDK. DPDK has adopted the atomic operations from
  https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html. These
  operations must be used for patches that need to be merged in 20.08 onwards.
  This change will not introduce any performance degradation.

* rte_smp_*mb: These APIs provide full barrier functionality. However, many
  use cases do not require full barriers. To support such use cases, DPDK has
  adopted atomic operations from
  https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html. These
  operations and a new wrapper ``rte_atomic_thread_fence`` instead of
  ``__atomic_thread_fence`` must be used for patches that need to be merged in
  20.08 onwards. This change will not introduce any performance degradation.

* mempool: Helper macro ``MEMPOOL_HEADER_SIZE()`` is deprecated and will
  be removed in DPDK 22.11. The replacement macro
  ``RTE_MEMPOOL_HEADER_SIZE()`` is internal only.

* mempool: Macro to register mempool driver ``MEMPOOL_REGISTER_OPS()`` is
  deprecated and will be removed in DPDK 22.11. Use replacement macro
  ``RTE_MEMPOOL_REGISTER_OPS()``.

* mempool: The mempool API macros ``MEMPOOL_PG_*`` are deprecated and
  will be removed in DPDK 22.11.

* pci: To reduce unnecessary ABIs exposed by DPDK bus driver, "rte_bus_pci.h"
  will be made internal in 21.11 and macros/data structures/functions defined
  in the header will not be considered as ABI anymore. This change is inspired
  by the RFC https://patchwork.dpdk.org/project/dpdk/list/?series=17176.

* lib: will fix extending some enum/define breaking the ABI. There are multiple
  samples in DPDK that enum/define terminated with a ``.*MAX.*`` value which is
  used by iterators, and arrays holding these values are sized with this
  ``.*MAX.*`` value. So extending this enum/define increases the ``.*MAX.*``
  value which increases the size of the array and depending on how/where the
  array is used this may break the ABI.
  ``RTE_ETH_FLOW_MAX`` is one sample of the mentioned case, adding a new flow
  type will break the ABI because of ``flex_mask[RTE_ETH_FLOW_MAX]`` array
  usage in following public struct hierarchy:
  ``rte_eth_fdir_flex_conf -> rte_eth_fdir_conf -> rte_eth_conf (in the middle)``.
  Need to identify this kind of usages and fix in 20.11, otherwise this blocks
  us extending existing enum/define.
  One solution can be using a fixed size array instead of ``.*MAX.*`` value.

* ethdev: The flow director API, including ``rte_eth_conf.fdir_conf`` field,
  and the related structures (``rte_fdir_*`` and ``rte_eth_fdir_*``),
  will be removed in DPDK 20.11.

* ethdev: Announce moving from dedicated modify function for each field,
  to using the general ``rte_flow_modify_field`` action.

* ethdev: The flow API matching pattern structures, ``struct rte_flow_item_*``,
  should start with relevant protocol header.
  Some matching pattern structures implements this by duplicating protocol header
  fields in the struct. To clarify the intention and to be sure protocol header
  is intact, will replace those fields with relevant protocol header struct.
  In v21.02 both individual protocol header fields and the protocol header struct
  will be added as union, target is switch usage to the protocol header by time.
  In v21.11 LTS, protocol header fields will be cleaned and only protocol header
  struct will remain.

* ethdev: Queue specific stats fields will be removed from ``struct rte_eth_stats``.
  Mentioned fields are: ``q_ipackets``, ``q_opackets``, ``q_ibytes``, ``q_obytes``,
  ``q_errors``.
  Instead queue stats will be received via xstats API. Current method support
  will be limited to maximum 256 queues.
  Also compile time flag ``RTE_ETHDEV_QUEUE_STAT_CNTRS`` will be removed.

* ethdev: Items and actions ``PF``, ``VF``, ``PHY_PORT``, ``PORT_ID`` are
  deprecated as hard-to-use / ambiguous and will be removed in DPDK 22.11.

* ethdev: The use of attributes ``ingress`` / ``egress`` in "transfer" flows
  is deprecated as ambiguous with respect to the embedded switch. The use of
  these attributes will become invalid starting from DPDK 22.11.

* ethdev: Actions ``OF_SET_MPLS_TTL``, ``OF_DEC_MPLS_TTL``, ``OF_SET_NW_TTL``,
  ``OF_COPY_TTL_OUT``, ``OF_COPY_TTL_IN`` are deprecated as not supported by
  any PMD, so they will be removed in DPDK 22.11.

* ethdev: Actions ``OF_DEC_NW_TTL``, ``SET_IPV4_SRC``, ``SET_IPV4_DST``,
  ``SET_IPV6_SRC``, ``SET_IPV6_DST``, ``SET_TP_SRC``, ``SET_TP_DST``,
  ``DEC_TTL``, ``SET_TTL``, ``SET_MAC_SRC``, ``SET_MAC_DST``, ``INC_TCP_SEQ``,
  ``DEC_TCP_SEQ``, ``INC_TCP_ACK``, ``DEC_TCP_ACK``, ``SET_IPV4_DSCP``,
  ``SET_IPV6_DSCP``, ``SET_TAG``, ``SET_META`` are marked as legacy and
  superseded by the generic MODIFY_FIELD action.
  The legacy actions should be deprecated in 22.07, once MODIFY_FIELD
  alternative is implemented.
  The legacy actions should be removed in DPDK 22.11.

* cryptodev: Hide structures ``rte_cryptodev_sym_session`` and
  ``rte_cryptodev_asym_session`` to remove unnecessary indirection between
  session and the private data of session. An opaque pointer can be exposed
  directly to application which can be attached to the ``rte_crypto_op``.

* security: Hide structure ``rte_security_session`` and expose an opaque
  pointer for the private data to the application which can be attached
  to the packet while enqueuing.

* metrics: The function ``rte_metrics_init`` will have a non-void return
  in order to notify errors instead of calling ``rte_exit``.

* raw/ioat: The ``ioat`` rawdev driver has been deprecated, since it's
  functionality is provided through the new ``dmadev`` infrastructure.
  To continue to use hardware previously supported by the ``ioat`` rawdev driver,
  applications should be updated to use the ``dmadev`` library instead,
  with the underlying HW-functionality being provided by the ``ioat`` or
  ``idxd`` dma drivers

* drivers/octeontx2: remove octeontx2 drivers

  In the view of enabling unified driver for ``octeontx2(cn9k)``/``octeontx3(cn10k)``,
  removing ``drivers/octeontx2`` drivers and replace with ``drivers/cnxk/`` which
  supports both ``octeontx2(cn9k)`` and ``octeontx3(cn10k)`` SoCs.
  This deprecation notice is to do following actions in DPDK v22.02 version.

  #. Replace ``drivers/common/octeontx2/`` with ``drivers/common/cnxk/``
  #. Replace ``drivers/mempool/octeontx2/`` with ``drivers/mempool/cnxk/``
  #. Replace ``drivers/net/octeontx2/`` with ``drivers/net/cnxk/``
  #. Replace ``drivers/event/octeontx2/`` with ``drivers/event/cnxk/``
  #. Replace ``drivers/crypto/octeontx2/`` with ``drivers/crypto/cnxk/``
  #. Rename ``drivers/regex/octeontx2/`` as ``drivers/regex/cn9k/``
  #. Rename ``config/arm/arm64_octeontx2_linux_gcc`` as ``config/arm/arm64_cn9k_linux_gcc``

  Last two actions are to align naming convention as cnxk scheme.
