Re: [dpdk-dev] [dpdk-stable] [PATCH v2] meter: provide experimental alias of API for old apps

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 5/14/2020 9:44 AM, Ray Kinsella wrote:
> 
> 
> On 13/05/2020 19:05, Ferruh Yigit wrote:
>> On v20.02 some meter APIs have been matured and symbols moved from
>> EXPERIMENTAL to DPDK_20.0.1 block.
>>
>> This can break the applications that were using these mentioned APIs on
>> v19.11. Although there is no modification on the APIs and the action is
>> positive and matures the APIs, the affect can be negative to
>> applications.
>>
>> Since experimental APIs can change or go away without notice as part of
>> contract, to prevent this negative affect that may occur by maturing
>> experimental API, a process update already suggested, which enables
>> aliasing without forcing it:
>> https://patches.dpdk.org/patch/65863/
>>
>> This patch provides aliasing by duplicating the existing and versioned
>> symbols as experimental.
>>
>> Since symbols moved from DPDK_20.0.1 to DPDK_21 block in the v20.05, the
>> aliasing done between EXPERIMENTAL and DPDK_21.
>>
>> Also following changes done to enabling aliasing:
>>
>> Created VERSION_SYMBOL_EXPERIMENTAL helper macro.
>>
>> Updated the 'check-experimental-syms.sh' buildtool, which was
>> complaining that the symbol is in EXPERIMENTAL tag in .map file but it
>> is not in the .experimental section (__rte_experimental tag is missing).
>> Updated tool in a way it won't complain if the symbol in the
>> EXPERIMENTAL tag duplicated in some other block in .map file (versioned)
>>
>> Enabled function versioning for meson build for the library.
>>
>> Fixes: 30512af820fe ("meter: remove experimental flag from RFC4115 trTCM API")
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>

<...>

>> @@ -46,6 +46,9 @@
>>   */
>>  #define VERSION_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", " RTE_STR(b) "@DPDK_" RTE_STR(n))
> 
> Please add
> 
> /*
>  * VERSION_SYMBOL_EXPERIMENTAL
>  * Creates a symbol version table entry binding the symbol <b>@EXPERIMENTAL to the internal
>  * function name <b><e>. The macro is used when a symbol matures to become part of the stable ABI,
>  * to provide an alias to experimental for some time.
>  */

done