Re: OFED-4.8, rdma-core, and library paths

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Tue, Feb 07, 2017 at 01:59:30PM -0700, Jason Gunthorpe wrote:
> On Tue, Feb 07, 2017 at 10:14:28PM +0200, Leon Romanovsky wrote:
>
> > > > Compile the library to build/lib/libibverbs-dv-mlx5.so.1.0.13
> > > > and setup a symlink build/lib/libmlx5-rdmav2.so -> libibverbs-dv-mlx5.so.1.0.13
> > >
> > > Just as a note, I'm calling it libmlx5 and not libibverbs-dv-mlx5.
>
> That will clash with the legacy providers, don't recommend it.

Is it real scenario? Will these legacy providers co-exists with
rdma-core library? I really don't like libibverbs-dv-mlx5 name, it is
too long and have feature name in the name.

>
> > > > For install, use realpath like this:
> > > >
> > > >  execute_process(COMMAND "realpath --relative-to ${VERBS_PROVIDER_DIR} ${CMAKE_INSTALL_LIBDIR}/libmlx5.so.1.0.13" OUTPUT_VARIBALE LINK_PATH)
> > >
> > > It doesn't work for me :(
>
> Ah realpath needs the paths to exist.. Sigha
>
> Another alternative is this:
>
> python -c "import os; print(os.path.relpath('/usr/lib64/libmlx4.so','/usr/lib64/libibverbs'));"

It prints to the screen, but doesn't update OUTPUT_VARAIBLE :(
115  execute_process(COMMAND python -c "import os; print(os.path.relpath('/usr/lib64/libmlx5.so','/usr/lib64/libibverbs'));"
116                 OUTPUT_VARIBALE LINK_PATH)
117   message(STATUS "link_path = ${LINK_PATH}")

..
-- Performing Test HAVE_C_WREDUNDANT_DECLS - Failed
../libmlx5.so
-- link_path =
-- Missing Optional Items:

>
> >   add_custom_target(share_link ALL DEPENDS "${DEST}"  COMMAND ${CMAKE_COMMAND} -E create_symlink "lib${DEST}.so.${VERSION}"
> > 	  "${BUILD_LIB}/lib${DEST}-rdmav2.so")
> >   add_dependencies(share_link ${DEST})
>
> The doesn't need a build time, just do:
>
>     execute_process(COMMAND "${CMAKE_COMMAND}" -E create_symlink
>                  "lib${DEST}.so.${VERSION}"
> 		 "${BUILD_LIB}/lib${DEST}-rdmav2.so")
>
> It creates a dangling link until compilation, which is fine..

In non-ninja builds, it doesn't create libmlx5-rdmav2.so symlink in
build/lib, because libmlx5.so is not created yet. This is why I ended
with custom target.

>
> >   install(FILES "${BUILD_LIB}/lib${DEST}-rdmav2.so" DESTINATION "${CMAKE_INSTALL_LIBDIR}")
>
> This line isn't needed, it is part of the next function

Not for build/lib

>
> >   rdma_install_symlink("${CMAKE_INSTALL_LIBDIR}/lib${DEST}.so.${VERSION}" "${VERBS_PROVIDER_DIR}/libmlx5-rdmav2.so")
>
> Should be
>
>    rdma_install_symlink("${CMAKE_INSTALL_LIBDIR}/lib${DEST}.so.${VERSION}" "${VERBS_PROVIDER_DIR}/lib${DEST}-rdmav2.so")a

Thanks for catching this.

>
> And most distros will not allow an absolute link under /usr which is
> why you need to make a relpath work and use that instead of
> ${CMAKE_INSTALL_LIBDIR}

It was my desperate attempt to make it work.

>
> Jason

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