Re: [PATCH] Add MO(mod objs) variable to process ext modules with subdirs

From: Randy Dunlap
Date: Tue Apr 02 2024 - 22:10:17 EST


Hi,

On 4/2/24 8:30 AM, Valerii Chernous wrote:
> The change allow to build external modules with nested makefiles.
> With current unofficial way(using "src" variable) it is posible to build

possible

> external(out of tree) kernel module with separating source and build
> artifacts dirs but with nested makefiles it doesn't work properly.
> Build system trap to recursion inside makefiles, articafts output dir

artifacts

> path grow with each iteration until exceed max path len and build failed
> Providing "MO" variable and using "override" directive with declaring
> "src" variable solve the problem
> Usage example:
> make -C KERNEL_SOURCE_TREE MO=BUILD_OUT_DIR M=EXT_MOD_SRC_DIR modules
>
> Cc: xe-linux-external@xxxxxxxxx
> Cc: Valerii Chernous <vchernou@xxxxxxxxx>
> Signed-off-by: Valerii Chernous <vchernou@xxxxxxxxx>
> ---
> Makefile | 17 +++++++++++++++++
> scripts/Makefile.build | 7 +++++++
> 2 files changed, 24 insertions(+)
>

If this code is going to be merged, there should also be a Documentation
update to Documentation/kbuild/{kbuild.rst,modules.rst}.

Thanks.
--
#Randy