Re: [dpdk-dev] [PATCH v3 5/5] net/mlx: fix overlinking with meson and glue dlopen

[Thomas Monjalon <thomas@monjalon.net>]

11/02/2020 12:32, Bruce Richardson:
> On Tue, Feb 11, 2020 at 02:19:42AM +0100, Thomas Monjalon wrote:
> > If ibverbs_link is dlopen, the PMD and application should not
> > be linked with ibverbs, but the glue library is.
> > Unfortunately the ibverbs dependency was exported in the
> > variable ext_deps, so there were overlinking.
> > 
> > It is fixed by not exporting the dependency in ext_deps,
> > and recreating a limited dependency object for cflags only.
> > 
> > Fixes: 1dd7c7e38c19 ("net/mlx4: support meson build")
> > Fixes: 96d7c62a70c7 ("net/mlx5: support meson build")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
> > ---
> >  drivers/common/mlx5/meson.build | 6 ++++--
> >  drivers/net/mlx4/meson.build    | 6 ++++--
> >  2 files changed, 8 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/common/mlx5/meson.build b/drivers/common/mlx5/meson.build
> > index 2bb2a83c45..2956fc20e2 100644
> > --- a/drivers/common/mlx5/meson.build
> > +++ b/drivers/common/mlx5/meson.build
> > @@ -30,7 +30,7 @@ foreach libname:libnames
> >  	endif
> >  	if lib.found()
> >  		libs += lib
> > -		if not static_ibverbs
> > +		if not static_ibverbs and not dlopen_ibverbs
> >  			ext_deps += lib
> >  		endif
> >  	else
> > @@ -38,10 +38,12 @@ foreach libname:libnames
> >  		reason = 'missing dependency, "' + libname + '"'
> >  	endif
> >  endforeach
> > -if build and static_ibverbs
> > +if build and (static_ibverbs or dlopen_ibverbs)
> >  	# Build without adding shared libs to Requires.private
> >  	ibv_cflags = run_command(pkgconf, '--cflags', 'libibverbs').stdout()
> >  	ext_deps += declare_dependency(compile_args: ibv_cflags.split())
> > +endif
> > +if build and static_ibverbs
> >  	# Add static deps ldflags to internal apps and Libs.private
> >  	ibv_ldflags = run_command(ldflags_ibverbs_static, check:true).stdout()
> >  	ext_deps += declare_dependency(link_args:ibv_ldflags.split())
> 
> One small suggestion:
> Since out minimum version of meson is 0.47.1, we can use subdir_done()
> function. Putting subdir_done() immediately after build=false will simplify
> things as you won't need to continually check the build variable in each if
> statement.

Great, thank you!