[dpdk-dev] [PATCH] eal: fix version macro

[dpdk-dev] [PATCH] eal: fix version macro

[Thomas Monjalon]

The macro RTE_VERSION is broken since updated with function calls.
It is a build-time version number, and must be built with macros.
For a run-time version number, there is the function rte_version().

Fixes: 5b637a848195 ("eal: fix querying DPDK version at runtime")
Cc: stable@dpdk.org

Reported-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
---
 lib/librte_eal/include/rte_version.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/include/rte_version.h b/lib/librte_eal/include/rte_version.h
index 2f3f727b46..736c5703be 100644
--- a/lib/librte_eal/include/rte_version.h
+++ b/lib/librte_eal/include/rte_version.h
@@ -28,10 +28,10 @@ extern "C" {
  * All version numbers in one to compare with RTE_VERSION_NUM()
  */
 #define RTE_VERSION RTE_VERSION_NUM( \
-			rte_version_year(), \
-			rte_version_month(), \
-			rte_version_minor(), \
-			rte_version_release())
+			RTE_VER_YEAR, \
+			RTE_VER_MONTH, \
+			RTE_VER_MINOR, \
+			RTE_VER_RELEASE)
 
 /**
  * Function to return DPDK version prefix string
-- 
2.30.1

Re: [dpdk-dev] [PATCH] eal: fix version macro

[David Marchand]

On Wed, Mar 17, 2021 at 10:31 AM Thomas Monjalon <thomas@monjalon.net> wrote:
>
> The macro RTE_VERSION is broken since updated with function calls.
> It is a build-time version number, and must be built with macros.
> For a run-time version number, there is the function rte_version().
>
> Fixes: 5b637a848195 ("eal: fix querying DPDK version at runtime")
> Cc: stable@dpdk.org
>
> Reported-by: David Marchand <david.marchand@redhat.com>
> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> ---
>  lib/librte_eal/include/rte_version.h | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/lib/librte_eal/include/rte_version.h b/lib/librte_eal/include/rte_version.h
> index 2f3f727b46..736c5703be 100644
> --- a/lib/librte_eal/include/rte_version.h
> +++ b/lib/librte_eal/include/rte_version.h
> @@ -28,10 +28,10 @@ extern "C" {
>   * All version numbers in one to compare with RTE_VERSION_NUM()
>   */
>  #define RTE_VERSION RTE_VERSION_NUM( \
> -                       rte_version_year(), \
> -                       rte_version_month(), \
> -                       rte_version_minor(), \
> -                       rte_version_release())
> +                       RTE_VER_YEAR, \
> +                       RTE_VER_MONTH, \
> +                       RTE_VER_MINOR, \
> +                       RTE_VER_RELEASE)
>
>  /**
>   * Function to return DPDK version prefix string

The original patch wanted to fix rte_version() at runtime.
I don't see the need to keep the rte_version_XXX exports now that
RTE_VERSION is reverted.


-- 
David Marchand

Re: [dpdk-dev] [PATCH] eal: fix version macro

[Thomas Monjalon]

17/03/2021 10:48, David Marchand:
> On Wed, Mar 17, 2021 at 10:31 AM Thomas Monjalon <thomas@monjalon.net> wrote:
> >
> > The macro RTE_VERSION is broken since updated with function calls.
> > It is a build-time version number, and must be built with macros.
> > For a run-time version number, there is the function rte_version().
> >
> > Fixes: 5b637a848195 ("eal: fix querying DPDK version at runtime")
> > Cc: stable@dpdk.org
> >
> > Reported-by: David Marchand <david.marchand@redhat.com>
> > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> > ---
> >  lib/librte_eal/include/rte_version.h | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/lib/librte_eal/include/rte_version.h b/lib/librte_eal/include/rte_version.h
> > index 2f3f727b46..736c5703be 100644
> > --- a/lib/librte_eal/include/rte_version.h
> > +++ b/lib/librte_eal/include/rte_version.h
> > @@ -28,10 +28,10 @@ extern "C" {
> >   * All version numbers in one to compare with RTE_VERSION_NUM()
> >   */
> >  #define RTE_VERSION RTE_VERSION_NUM( \
> > -                       rte_version_year(), \
> > -                       rte_version_month(), \
> > -                       rte_version_minor(), \
> > -                       rte_version_release())
> > +                       RTE_VER_YEAR, \
> > +                       RTE_VER_MONTH, \
> > +                       RTE_VER_MINOR, \
> > +                       RTE_VER_RELEASE)
> >
> >  /**
> >   * Function to return DPDK version prefix string
> 
> The original patch wanted to fix rte_version() at runtime.
> I don't see the need to keep the rte_version_XXX exports now that
> RTE_VERSION is reverted.

I think it may help to query the version numbers at runtime,
in "if" condition. Is there another way I'm missing?
We may argue that the runtime version number should not be used
to decide how to behave in an application.

Re: [dpdk-dev] [PATCH] eal: fix version macro

[David Marchand]

On Wed, Mar 17, 2021 at 10:31 AM Thomas Monjalon <thomas@monjalon.net> wrote:
>
> The macro RTE_VERSION is broken since updated with function calls.
> It is a build-time version number, and must be built with macros.
> For a run-time version number, there is the function rte_version().
>
> Fixes: 5b637a848195 ("eal: fix querying DPDK version at runtime")
> Cc: stable@dpdk.org
>
> Reported-by: David Marchand <david.marchand@redhat.com>
> Signed-off-by: Thomas Monjalon <thomas@monjalon.net>

Acked-by: David Marchand <david.marchand@redhat.com>

Let's discuss the versioning of the new symbols in the other thread.
Thanks.

-- 
David Marchand

Re: [dpdk-dev] [PATCH] eal: fix version macro

[Thomas Monjalon]

17/03/2021 16:36, David Marchand:
> On Wed, Mar 17, 2021 at 10:31 AM Thomas Monjalon <thomas@monjalon.net> wrote:
> >
> > The macro RTE_VERSION is broken since updated with function calls.
> > It is a build-time version number, and must be built with macros.
> > For a run-time version number, there is the function rte_version().
> >
> > Fixes: 5b637a848195 ("eal: fix querying DPDK version at runtime")
> > Cc: stable@dpdk.org
> >
> > Reported-by: David Marchand <david.marchand@redhat.com>
> > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> 
> Acked-by: David Marchand <david.marchand@redhat.com>

Applied quickly because the compilation of some apps are broken.

> Let's discuss the versioning of the new symbols in the other thread.

OK, in this thread:
https://inbox.dpdk.org/dev/20210317151535.1412311-1-thomas@monjalon.net/

Re: [dpdk-dev] [PATCH] eal: fix version macro

[Bruce Richardson]

On Wed, Mar 17, 2021 at 11:01:25AM +0100, Thomas Monjalon wrote:
> 17/03/2021 10:48, David Marchand:
> > On Wed, Mar 17, 2021 at 10:31 AM Thomas Monjalon <thomas@monjalon.net> wrote:
> > >
> > > The macro RTE_VERSION is broken since updated with function calls.
> > > It is a build-time version number, and must be built with macros.
> > > For a run-time version number, there is the function rte_version().
> > >
> > > Fixes: 5b637a848195 ("eal: fix querying DPDK version at runtime")
> > > Cc: stable@dpdk.org
> > >
> > > Reported-by: David Marchand <david.marchand@redhat.com>
> > > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> > > ---
> > >  lib/librte_eal/include/rte_version.h | 8 ++++----
> > >  1 file changed, 4 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/lib/librte_eal/include/rte_version.h b/lib/librte_eal/include/rte_version.h
> > > index 2f3f727b46..736c5703be 100644
> > > --- a/lib/librte_eal/include/rte_version.h
> > > +++ b/lib/librte_eal/include/rte_version.h
> > > @@ -28,10 +28,10 @@ extern "C" {
> > >   * All version numbers in one to compare with RTE_VERSION_NUM()
> > >   */
> > >  #define RTE_VERSION RTE_VERSION_NUM( \
> > > -                       rte_version_year(), \
> > > -                       rte_version_month(), \
> > > -                       rte_version_minor(), \
> > > -                       rte_version_release())
> > > +                       RTE_VER_YEAR, \
> > > +                       RTE_VER_MONTH, \
> > > +                       RTE_VER_MINOR, \
> > > +                       RTE_VER_RELEASE)
> > >
> > >  /**
> > >   * Function to return DPDK version prefix string
> > 
> > The original patch wanted to fix rte_version() at runtime.
> > I don't see the need to keep the rte_version_XXX exports now that
> > RTE_VERSION is reverted.
> 
> I think it may help to query the version numbers at runtime,
> in "if" condition. Is there another way I'm missing?
> We may argue that the runtime version number should not be used
> to decide how to behave in an application.
> 
I would also tend toward keeping them, for the same reason that runtime is
definitely to be preferred over build time, and they are not like to be
much of a maintenance burden.

Also, next time we have an ABI break, I wonder if the existing macros
should be renamed to have an RTE_BUILD_VER_ prefix, to make it clear that
it's the build version only that is being reported rather than the version
actually being used. Similarly the functions could be renamed to have
rte_runtime_ prefix, ensuring that in all cases the user is clear whether
they are getting the build version or the runtime version.

/Bruce

Re: [dpdk-dev] [PATCH] eal: fix version macro

[Thomas Monjalon]

18/03/2021 13:28, Bruce Richardson:
> On Wed, Mar 17, 2021 at 11:01:25AM +0100, Thomas Monjalon wrote:
> > 17/03/2021 10:48, David Marchand:
> > > On Wed, Mar 17, 2021 at 10:31 AM Thomas Monjalon <thomas@monjalon.net> wrote:
> > > >
> > > > The macro RTE_VERSION is broken since updated with function calls.
> > > > It is a build-time version number, and must be built with macros.
> > > > For a run-time version number, there is the function rte_version().
> > > >
> > > > Fixes: 5b637a848195 ("eal: fix querying DPDK version at runtime")
> > > > Cc: stable@dpdk.org
> > > >
> > > > Reported-by: David Marchand <david.marchand@redhat.com>
> > > > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> > > > ---
> > > >  lib/librte_eal/include/rte_version.h | 8 ++++----
> > > >  1 file changed, 4 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/lib/librte_eal/include/rte_version.h b/lib/librte_eal/include/rte_version.h
> > > > index 2f3f727b46..736c5703be 100644
> > > > --- a/lib/librte_eal/include/rte_version.h
> > > > +++ b/lib/librte_eal/include/rte_version.h
> > > > @@ -28,10 +28,10 @@ extern "C" {
> > > >   * All version numbers in one to compare with RTE_VERSION_NUM()
> > > >   */
> > > >  #define RTE_VERSION RTE_VERSION_NUM( \
> > > > -                       rte_version_year(), \
> > > > -                       rte_version_month(), \
> > > > -                       rte_version_minor(), \
> > > > -                       rte_version_release())
> > > > +                       RTE_VER_YEAR, \
> > > > +                       RTE_VER_MONTH, \
> > > > +                       RTE_VER_MINOR, \
> > > > +                       RTE_VER_RELEASE)
> > > >
> > > >  /**
> > > >   * Function to return DPDK version prefix string
> > > 
> > > The original patch wanted to fix rte_version() at runtime.
> > > I don't see the need to keep the rte_version_XXX exports now that
> > > RTE_VERSION is reverted.
> > 
> > I think it may help to query the version numbers at runtime,
> > in "if" condition. Is there another way I'm missing?
> > We may argue that the runtime version number should not be used
> > to decide how to behave in an application.
> > 
> I would also tend toward keeping them, for the same reason that runtime is
> definitely to be preferred over build time, and they are not like to be
> much of a maintenance burden.
> 
> Also, next time we have an ABI break, I wonder if the existing macros
> should be renamed to have an RTE_BUILD_VER_ prefix, to make it clear that
> it's the build version only that is being reported rather than the version
> actually being used. Similarly the functions could be renamed to have
> rte_runtime_ prefix, ensuring that in all cases the user is clear whether
> they are getting the build version or the runtime version.

I am fine with such rename,
but that's already quite clear that a macro is at build time,
and a function is usually evaluated at runtime.

Re: [dpdk-dev] [PATCH] eal: fix version macro

[Bruce Richardson]

On Thu, Mar 18, 2021 at 03:41:35PM +0100, Thomas Monjalon wrote:
> 18/03/2021 13:28, Bruce Richardson:
> > On Wed, Mar 17, 2021 at 11:01:25AM +0100, Thomas Monjalon wrote:
> > > 17/03/2021 10:48, David Marchand:
> > > > On Wed, Mar 17, 2021 at 10:31 AM Thomas Monjalon <thomas@monjalon.net> wrote:
> > > > >
> > > > > The macro RTE_VERSION is broken since updated with function calls.
> > > > > It is a build-time version number, and must be built with macros.
> > > > > For a run-time version number, there is the function rte_version().
> > > > >
> > > > > Fixes: 5b637a848195 ("eal: fix querying DPDK version at runtime")
> > > > > Cc: stable@dpdk.org
> > > > >
> > > > > Reported-by: David Marchand <david.marchand@redhat.com>
> > > > > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> > > > > ---
> > > > >  lib/librte_eal/include/rte_version.h | 8 ++++----
> > > > >  1 file changed, 4 insertions(+), 4 deletions(-)
> > > > >
> > > > > diff --git a/lib/librte_eal/include/rte_version.h b/lib/librte_eal/include/rte_version.h
> > > > > index 2f3f727b46..736c5703be 100644
> > > > > --- a/lib/librte_eal/include/rte_version.h
> > > > > +++ b/lib/librte_eal/include/rte_version.h
> > > > > @@ -28,10 +28,10 @@ extern "C" {
> > > > >   * All version numbers in one to compare with RTE_VERSION_NUM()
> > > > >   */
> > > > >  #define RTE_VERSION RTE_VERSION_NUM( \
> > > > > -                       rte_version_year(), \
> > > > > -                       rte_version_month(), \
> > > > > -                       rte_version_minor(), \
> > > > > -                       rte_version_release())
> > > > > +                       RTE_VER_YEAR, \
> > > > > +                       RTE_VER_MONTH, \
> > > > > +                       RTE_VER_MINOR, \
> > > > > +                       RTE_VER_RELEASE)
> > > > >
> > > > >  /**
> > > > >   * Function to return DPDK version prefix string
> > > > 
> > > > The original patch wanted to fix rte_version() at runtime.
> > > > I don't see the need to keep the rte_version_XXX exports now that
> > > > RTE_VERSION is reverted.
> > > 
> > > I think it may help to query the version numbers at runtime,
> > > in "if" condition. Is there another way I'm missing?
> > > We may argue that the runtime version number should not be used
> > > to decide how to behave in an application.
> > > 
> > I would also tend toward keeping them, for the same reason that runtime is
> > definitely to be preferred over build time, and they are not like to be
> > much of a maintenance burden.
> > 
> > Also, next time we have an ABI break, I wonder if the existing macros
> > should be renamed to have an RTE_BUILD_VER_ prefix, to make it clear that
> > it's the build version only that is being reported rather than the version
> > actually being used. Similarly the functions could be renamed to have
> > rte_runtime_ prefix, ensuring that in all cases the user is clear whether
> > they are getting the build version or the runtime version.
> 
> I am fine with such rename,
> but that's already quite clear that a macro is at build time,
> and a function is usually evaluated at runtime.
> 

If we take the existing rte_version function, without checking the source
code, one has no way of checking if that is resolved at runtime (as it is
now) or at compile-time (as it was). However, if we assume that that is a
bug and that all such functions should be run-time operations, then
there is no difficulty.

/Bruce