22. ABI and API Deprecation

See the guidelines document for details of the ABI policy. API and ABI deprecation notices are to be posted here.

22.1. Deprecation Notices

  • meson: The minimum supported version of meson for configuring and building DPDK will be increased to v0.47.1 (from 0.41) from DPDK 19.05 onwards. For those users with a version earlier than 0.47.1, an updated copy of meson can be got using the pip, or pip3, tool for downloading python packages.
  • 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.
  • eal: both declaring and identifying devices will be streamlined in v18.11. New functions will appear to query a specific port from buses, classes of device and device drivers. Device declaration will be made coherent with the new scheme of device identification. As such, rte_devargs device representation will change.
    • The enum rte_devtype was used to identify a bus and will disappear.
    • Functions previously deprecated will change or disappear:
      • rte_eal_devargs_type_count
  • eal: The rte_logs struct and global symbol will be made private to remove it from the externally visible ABI and allow it to be updated in the future.
  • igb_uio: In the view of reducing the kernel dependency from the main tree, as a first step, the Technical Board decided to move igb_uio kernel module to the dpdk-kmods repository in the /linux/igb_uio/ directory in 20.11. Minutes of Technical Board Meeting of 2019-11-06.
  • 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_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.
  • dpaa2: removal of rte_dpaa2_memsegs structure which has been replaced by a pa-va search library. This structure was earlier being used for holding memory segments used by dpaa2 driver for faster pa->va translation. This structure would be made internal (or removed if all dependencies are cleared) in future releases.
  • mempool: starting from v20.05, the API of rte_mempool_populate_iova() and rte_mempool_populate_virt() will change to return 0 instead of -EINVAL when there is not enough room to store one object. The ABI will be preserved until 20.11.
  • ethdev: the legacy filter API, including rte_eth_dev_filter_supported(), rte_eth_dev_filter_ctrl() as well as filter types MACVLAN, ETHERTYPE, FLEXIBLE, SYN, NTUPLE, TUNNEL, FDIR, HASH and L2_TUNNEL, is superseded by the generic flow API (rte_flow) in PMDs that implement the latter. Target release for removal of the legacy API will be defined once most PMDs have switched to rte_flow.
  • ethdev: Update API functions returning void to return int with negative errno values to indicate various error conditions (e.g. invalid port ID, unsupported operation, failed operation):
    • rte_eth_dev_stop
    • rte_eth_dev_close
  • ethdev: New offload flags DEV_RX_OFFLOAD_FLOW_MARK will be added in 19.11. This will allow application to enable or disable PMDs from updating rte_mbuf::hash::fdir. This scheme will allow PMDs to avoid writes to rte_mbuf fields on Rx and thereby improve Rx performance if application wishes do so. In 19.11 PMDs will still update the field even when the offload is not enabled.
  • cryptodev: support for using IV with all sizes is added, J0 still can be used but only when IV length in following structs rte_crypto_auth_xform, rte_crypto_aead_xform is set to zero. When IV length is greater or equal to one it means it represents IV, when is set to zero it means J0 is used directly, in this case 16 bytes of J0 need to be passed.
  • sched: To allow more traffic classes, flexible mapping of pipe queues to traffic classes, and subport level configuration of pipes and queues changes will be made to macros, data structures and API functions defined in “rte_sched.h”. These changes are aligned to improvements suggested in the RFC https://mails.dpdk.org/archives/dev/2018-November/120035.html.
  • metrics: The function rte_metrics_init will have a non-void return in order to notify errors instead of calling rte_exit.
  • power: rte_power_set_env function will no longer return 0 on attempt to set new power environment if power environment was already initialized. In this case the function will return -1 unless the environment is unset first (using rte_power_unset_env). Other function usage scenarios will not change.
  • python: Since the beginning of 2020, Python 2 has officially reached end-of-support: https://www.python.org/doc/sunset-python-2/. Python 2 support will be completely removed in 20.11. In 20.08, explicit deprecation warnings will be displayed when running scripts with Python 2.