14/02/2022 11:16, Ray Kinsella: > Ray Kinsella <m...@ashroe.eu> writes: > > Thomas Monjalon <tho...@monjalon.net> writes: > >> 02/02/2022 12:44, Ray Kinsella: > >>> Ferruh Yigit <ferruh.yi...@intel.com> writes: > >>> > On 1/28/2022 12:48 PM, Kalesh A P wrote: > >>> >> --- a/lib/ethdev/rte_ethdev.h > >>> >> +++ b/lib/ethdev/rte_ethdev.h > >>> >> @@ -3818,6 +3818,24 @@ enum rte_eth_event_type { > >>> >> RTE_ETH_EVENT_DESTROY, /**< port is released */ > >>> >> RTE_ETH_EVENT_IPSEC, /**< IPsec offload related event */ > >>> >> RTE_ETH_EVENT_FLOW_AGED,/**< New aged-out flows is detected */ > >>> >> + RTE_ETH_EVENT_ERR_RECOVERING, > >>> >> + /**< port recovering from an error > >>> >> + * > >>> >> + * PMD detected a FW reset or error condition. > >>> >> + * PMD will try to recover from the error. > >>> >> + * Data path may be quiesced and Control path > >>> >> operations > >>> >> + * may fail at this time. > >>> >> + */ > >>> >> + RTE_ETH_EVENT_RECOVERED, > >>> >> + /**< port recovered from an error > >>> >> + * > >>> >> + * PMD has recovered from the error condition. > >>> >> + * Control path and Data path are up now. > >>> >> + * PMD re-configures the port to the state > >>> >> prior to the error. > >>> >> + * Since the device has undergone a reset, flow > >>> >> rules > >>> >> + * offloaded prior to reset may be lost and > >>> >> + * the application should recreate the rules > >>> >> again. > >>> >> + */ > >>> >> RTE_ETH_EVENT_MAX /**< max value of this enum */ > >>> > > >>> > > >>> > Also ABI check complains about 'RTE_ETH_EVENT_MAX' value check, cc'ed > >>> > more people > >>> > to evaluate if it is a false positive: > >>> > > >>> > > >>> > 1 function with some indirect sub-type change: > >>> > [C] 'function int rte_eth_dev_callback_register(uint16_t, > >>> > rte_eth_event_type, rte_eth_dev_cb_fn, void*)' at rte_ethdev.c:4637:1 > >>> > has some indirect sub-type changes: > >>> > parameter 3 of type 'typedef rte_eth_dev_cb_fn' has sub-type > >>> > changes: > >>> > underlying type 'int (typedef uint16_t, enum rte_eth_event_type, > >>> > void*, void*)*' changed: > >>> > in pointed to type 'function type int (typedef uint16_t, enum > >>> > rte_eth_event_type, void*, void*)': > >>> > parameter 2 of type 'enum rte_eth_event_type' has sub-type > >>> > changes: > >>> > type size hasn't changed > >>> > 2 enumerator insertions: > >>> > 'rte_eth_event_type::RTE_ETH_EVENT_ERR_RECOVERING' value > >>> > '11' > >>> > 'rte_eth_event_type::RTE_ETH_EVENT_RECOVERED' value '12' > >>> > 1 enumerator change: > >>> > 'rte_eth_event_type::RTE_ETH_EVENT_MAX' from value '11' > >>> > to '13' at rte_ethdev.h:3807:1 > >>> > >>> I don't immediately see the problem that this would cause. > >>> There are no array sizes etc dependent on the value of MAX for instance. > >>> > >>> Looks safe? > >> > >> We never know how this enum will be used by the application. > >> The max value may be used for the size of an event array. > >> It looks a real ABI issue unfortunately. > > > > Right - but we only really care about it when an array size based on MAX > > is likely to be passed to DPDK, which doesn't apply in this case.
I don't completely agree. A developer may assume an event will never exceed MAX value. However, after an upgrade of DPDK without app rebuild, a higher event value may be received in the app, breaking the assumption. Should we consider this case as an ABI breakage? > > I noted that some Linux folks explicitly mark similar MAX values as not > > part of the ABI. > > > > /usr/include/linux/perf_event.h > > 37: PERF_TYPE_MAX, /* non-ABI */ > > 60: PERF_COUNT_HW_MAX, /* non-ABI */ > > 79: PERF_COUNT_HW_CACHE_MAX, /* non-ABI */ > > 87: PERF_COUNT_HW_CACHE_OP_MAX, /* non-ABI */ > > 94: PERF_COUNT_HW_CACHE_RESULT_MAX, /* non-ABI */ > > 116: PERF_COUNT_SW_MAX, /* non-ABI */ > > 149: PERF_SAMPLE_MAX = 1U << 24, /* non-ABI */ > > 151: __PERF_SAMPLE_CALLCHAIN_EARLY = 1ULL << 63, /* > > non-ABI; internal use */ > > 189: PERF_SAMPLE_BRANCH_MAX_SHIFT /* non-ABI */ > > 267: PERF_TXN_MAX = (1 << 8), /* non-ABI */ > > 301: PERF_FORMAT_MAX = 1U << 4, /* non-ABI */ > > 1067: PERF_RECORD_MAX, /* non-ABI */ > > 1078: PERF_RECORD_KSYMBOL_TYPE_MAX /* non-ABI */ > > 1087: PERF_BPF_EVENT_MAX, /* non-ABI */ > > Any thoughts on similarly annotating all our _MAX enums in the same way? > We could also add a section in the ABI Policy to make it explicit _MAX > enum values are not part of the ABI - what do folks think? Interesting. I am not sure it is always ABI-safe though.