Hi Ferruh,
> -----Original Message-----
> From: Yigit, Ferruh <ferruh.yi...@intel.com>
> Sent: Thursday, May 14, 2020 5:11 PM
> To: Ray Kinsella <m...@ashroe.eu>; Neil Horman
> <nhor...@tuxdriver.com>; Dumitrescu, Cristian
> <cristian.dumitre...@intel.com>; Eelco Chaudron <echau...@redhat.com>
> Cc: dev@dpdk.org; Yigit, Ferruh <ferruh.yi...@intel.com>; Thomas Monjalon
> <tho...@monjalon.net>; David Marchand <david.march...@redhat.com>;
> sta...@dpdk.org; Luca Boccassi <bl...@debian.org>; Richardson, Bruce
> <bruce.richard...@intel.com>; Stokes, Ian <ian.sto...@intel.com>; Andrzej
> Ostruszka <a...@semihalf.com>
> Subject: [PATCH v4] meter: provide experimental alias of API for old apps
>
> 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/
>
Personally, I am not convinced this is really needed.
Are there any users asking for this?
Is there any other library where this is also applied, or is librte_meter the
only library?
> 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-symbols.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: sta...@dpdk.org
>
> Signed-off-by: Ferruh Yigit <ferruh.yi...@intel.com>
> ---
> Cc: Neil Horman <nhor...@tuxdriver.com>
> Cc: Thomas Monjalon <tho...@monjalon.net>
> Cc: Luca Boccassi <bl...@debian.org>
> Cc: David Marchand <david.march...@redhat.com>
> Cc: Bruce Richardson <bruce.richard...@intel.com>
> Cc: Ian Stokes <ian.sto...@intel.com>
> Cc: Eelco Chaudron <echau...@redhat.com>
> Cc: Andrzej Ostruszka <a...@semihalf.com>
> Cc: Ray Kinsella <m...@ashroe.eu>
>
> v2:
> * Commit log updated
>
> v3:
> * added suggested comment to VERSION_SYMBOL_EXPERIMENTAL macro
>
> v4:
> * update script name in commit log, remove empty line
> ---
> buildtools/check-symbols.sh | 3 +-
> .../include/rte_function_versioning.h | 9 +++
> lib/librte_meter/meson.build | 1 +
> lib/librte_meter/rte_meter.c | 59 ++++++++++++++++++-
> lib/librte_meter/rte_meter_version.map | 8 +++
> 5 files changed, 76 insertions(+), 4 deletions(-)
>
> diff --git a/buildtools/check-symbols.sh b/buildtools/check-symbols.sh
> index 3df57c322c..e407553a34 100755
> --- a/buildtools/check-symbols.sh
> +++ b/buildtools/check-symbols.sh
> @@ -26,7 +26,8 @@ ret=0
> for SYM in `$LIST_SYMBOL -S EXPERIMENTAL $MAPFILE |cut -d ' ' -f 3`
> do
> if grep -q "\.text.*[[:space:]]$SYM$" $DUMPFILE &&
> - ! grep -q "\.text\.experimental.*[[:space:]]$SYM$"
> $DUMPFILE
> + ! grep -q "\.text\.experimental.*[[:space:]]$SYM$"
> $DUMPFILE &&
> + $LIST_SYMBOL -s $SYM $MAPFILE | grep -q EXPERIMENTAL
> then
> cat >&2 <<- END_OF_MESSAGE
> $SYM is not flagged as experimental
> diff --git a/lib/librte_eal/include/rte_function_versioning.h
> b/lib/librte_eal/include/rte_function_versioning.h
> index b9f862d295..f588f2643b 100644
> --- a/lib/librte_eal/include/rte_function_versioning.h
> +++ b/lib/librte_eal/include/rte_function_versioning.h
> @@ -46,6 +46,14 @@
> */
> #define VERSION_SYMBOL(b, e, n) __asm__(".symver " RTE_STR(b)
> RTE_STR(e) ", " RTE_STR(b) "@DPDK_" RTE_STR(n))
>
> +/*
> + * 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
> @@ -79,6 +87,7 @@
> * No symbol versioning in use
> */
> #define VERSION_SYMBOL(b, e, n)
> +#define VERSION_SYMBOL_EXPERIMENTAL(b, e)
> #define __vsym
> #define BIND_DEFAULT_SYMBOL(b, e, n)
> #define MAP_STATIC_SYMBOL(f, p) f __attribute__((alias(RTE_STR(p))))
> diff --git a/lib/librte_meter/meson.build b/lib/librte_meter/meson.build
> index 646fd4d43f..fce0368437 100644
> --- a/lib/librte_meter/meson.build
> +++ b/lib/librte_meter/meson.build
> @@ -3,3 +3,4 @@
>
> sources = files('rte_meter.c')
> headers = files('rte_meter.h')
> +use_function_versioning = true
> diff --git a/lib/librte_meter/rte_meter.c b/lib/librte_meter/rte_meter.c
> index da01429a8b..c600b05064 100644
> --- a/lib/librte_meter/rte_meter.c
> +++ b/lib/librte_meter/rte_meter.c
> @@ -9,6 +9,7 @@
> #include <rte_common.h>
> #include <rte_log.h>
> #include <rte_cycles.h>
> +#include <rte_function_versioning.h>
>
> #include "rte_meter.h"
>
> @@ -119,8 +120,8 @@ rte_meter_trtcm_config(struct rte_meter_trtcm *m,
> return 0;
> }
>
> -int
> -rte_meter_trtcm_rfc4115_profile_config(
> +static int
> +rte_meter_trtcm_rfc4115_profile_config_(
> struct rte_meter_trtcm_rfc4115_profile *p,
> struct rte_meter_trtcm_rfc4115_params *params)
> {
> @@ -145,7 +146,35 @@ rte_meter_trtcm_rfc4115_profile_config(
> }
>
> int
> -rte_meter_trtcm_rfc4115_config(
> +rte_meter_trtcm_rfc4115_profile_config_s(
> + struct rte_meter_trtcm_rfc4115_profile *p,
> + struct rte_meter_trtcm_rfc4115_params *params);
> +int
> +rte_meter_trtcm_rfc4115_profile_config_s(
> + struct rte_meter_trtcm_rfc4115_profile *p,
> + struct rte_meter_trtcm_rfc4115_params *params)
> +{
> + return rte_meter_trtcm_rfc4115_profile_config_(p, params);
> +}
> +BIND_DEFAULT_SYMBOL(rte_meter_trtcm_rfc4115_profile_config, _s, 21);
> +MAP_STATIC_SYMBOL(int rte_meter_trtcm_rfc4115_profile_config(struct
> rte_meter_trtcm_rfc4115_profile *p,
> + struct rte_meter_trtcm_rfc4115_params *params),
> rte_meter_trtcm_rfc4115_profile_config_s);
> +
> +int
> +rte_meter_trtcm_rfc4115_profile_config_e(
> + struct rte_meter_trtcm_rfc4115_profile *p,
> + struct rte_meter_trtcm_rfc4115_params *params);
> +int
> +rte_meter_trtcm_rfc4115_profile_config_e(
> + struct rte_meter_trtcm_rfc4115_profile *p,
> + struct rte_meter_trtcm_rfc4115_params *params)
> +{
> + return rte_meter_trtcm_rfc4115_profile_config_(p, params);
> +}
> +VERSION_SYMBOL_EXPERIMENTAL(rte_meter_trtcm_rfc4115_profile_conf
> ig, _e);
> +
> +static int
> +rte_meter_trtcm_rfc4115_config_(
> struct rte_meter_trtcm_rfc4115 *m,
> struct rte_meter_trtcm_rfc4115_profile *p)
> {
> @@ -160,3 +189,27 @@ rte_meter_trtcm_rfc4115_config(
>
> return 0;
> }
> +
> +int
> +rte_meter_trtcm_rfc4115_config_s(struct rte_meter_trtcm_rfc4115 *m,
> + struct rte_meter_trtcm_rfc4115_profile *p);
> +int
> +rte_meter_trtcm_rfc4115_config_s(struct rte_meter_trtcm_rfc4115 *m,
> + struct rte_meter_trtcm_rfc4115_profile *p)
> +{
> + return rte_meter_trtcm_rfc4115_config_(m, p);
> +}
> +BIND_DEFAULT_SYMBOL(rte_meter_trtcm_rfc4115_config, _s, 21);
> +MAP_STATIC_SYMBOL(int rte_meter_trtcm_rfc4115_config(struct
> rte_meter_trtcm_rfc4115 *m,
> + struct rte_meter_trtcm_rfc4115_profile *p),
> rte_meter_trtcm_rfc4115_config_s);
> +
> +int
> +rte_meter_trtcm_rfc4115_config_e(struct rte_meter_trtcm_rfc4115 *m,
> + struct rte_meter_trtcm_rfc4115_profile *p);
> +int
> +rte_meter_trtcm_rfc4115_config_e(struct rte_meter_trtcm_rfc4115 *m,
> + struct rte_meter_trtcm_rfc4115_profile *p)
> +{
> + return rte_meter_trtcm_rfc4115_config_(m, p);
> +}
> +VERSION_SYMBOL_EXPERIMENTAL(rte_meter_trtcm_rfc4115_config, _e);
To me, this is a significant amount of dead code that does not add any
functionality and does not bring any added value to the library for any user. I
am not a build system expert, but I would definitely prefer avoiding adding any
C code to the library for this purpose, and just modify the map file, would
this approach be possible?
Also, very important, is this C code to be added permanently or is it added
just on a temporary basis? If temporary, when is it going to be removed?
> diff --git a/lib/librte_meter/rte_meter_version.map
> b/lib/librte_meter/rte_meter_version.map
> index 2c7dadbcac..b493bcebe9 100644
> --- a/lib/librte_meter/rte_meter_version.map
> +++ b/lib/librte_meter/rte_meter_version.map
> @@ -20,4 +20,12 @@ DPDK_21 {
> rte_meter_trtcm_rfc4115_color_blind_check;
> rte_meter_trtcm_rfc4115_config;
> rte_meter_trtcm_rfc4115_profile_config;
> +
> } DPDK_20.0;
> +
> +EXPERIMENTAL {
> + global:
> +
> + rte_meter_trtcm_rfc4115_config;
> + rte_meter_trtcm_rfc4115_profile_config;
> +};
> --
> 2.25.4
Regards,
Cristian
