29. ABI and API Deprecation

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

29.1. 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.

  1. Replace drivers/common/octeontx2/ with drivers/common/cnxk/
  2. Replace drivers/mempool/octeontx2/ with drivers/mempool/cnxk/
  3. Replace drivers/net/octeontx2/ with drivers/net/cnxk/
  4. Replace drivers/event/octeontx2/ with drivers/event/cnxk/
  5. Replace drivers/crypto/octeontx2/ with drivers/crypto/cnxk/
  6. Rename drivers/regex/octeontx2/ as drivers/regex/cn9k/
  7. 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.