[dpdk-dev] [PATCH v3] meter: provide experimental alias of API for old apps

[David Marchand]

On Thu, May 14, 2020 at 1:52 PM Ferruh Yigit <ferruh.yigit at intel.com> 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.

This helper (+ script update) must come with the process update: the
macro is referenced in its v5 revision.


>
> Updated the 'check-experimental-syms.sh' buildtool, which was

Nit: the script name changed.


> diff --git a/lib/librte_eal/include/rte_function_versioning.h b/lib/librte_eal/include/rte_function_versioning.h
> index b9f862d295..534a8bff95 100644
> --- a/lib/librte_eal/include/rte_function_versioning.h
> +++ b/lib/librte_eal/include/rte_function_versioning.h
> @@ -46,6 +46,15 @@
>   */
>  #define VERSION_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", " RTE_STR(b) "@DPDK_" RTE_STR(n))
>
> +

No need for this newline.

> +/*
> + * 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.
> + */
> +#define VERSION_SYMBOL_EXPERIMENTAL(b, e) __asm__(".symver " RTE_STR(b) RTE_STR(e) ", " RTE_STR(b) "@EXPERIMENTAL")
> +
>  /*
>   * BIND_DEFAULT_SYMBOL
>   * Creates a symbol version entry instructing the linker to bind references to


-- 
David Marchand