Re: [PATCH 5.4] kbuild: Fix include path in scripts/Makefile.modpost

[Greg KH <greg@kroah.com>]

On Wed, Aug 31, 2022 at 06:17:24AM +0200, Nicolas Schier wrote:
> From: Jing Leng <jleng@ambarella.com>
> 
> commit 23a0cb8e3225122496bfa79172005c587c2d64bf upstream.
> 
> When building an external module, if users don't need to separate the
> compilation output and source code, they run the following command:
> "make -C $(LINUX_SRC_DIR) M=$(PWD)". At this point, "$(KBUILD_EXTMOD)"
> and "$(src)" are the same.
> 
> If they need to separate them, they run "make -C $(KERNEL_SRC_DIR)
> O=$(KERNEL_OUT_DIR) M=$(OUT_DIR) src=$(PWD)". Before running the
> command, they need to copy "Kbuild" or "Makefile" to "$(OUT_DIR)" to
> prevent compilation failure.
> 
> So the kernel should change the included path to avoid the copy operation.
> 
> Signed-off-by: Jing Leng <jleng@ambarella.com>
> [masahiro: I do not think "M=$(OUT_DIR) src=$(PWD)" is the official way,
> but this patch is a nice clean up anyway.]
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> [nsc: updated context for v5.4]
> Signed-off-by: Nicolas Schier <n.schier@avm.de>
> ---
>  scripts/Makefile.modpost | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
> index 48585c4d04ad..0273bf7375e2 100644
> --- a/scripts/Makefile.modpost
> +++ b/scripts/Makefile.modpost
> @@ -87,8 +87,7 @@ obj := $(KBUILD_EXTMOD)
>  src := $(obj)
>  
>  # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
> -include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
> -             $(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
> +include $(if $(wildcard $(src)/Kbuild), $(src)/Kbuild, $(src)/Makefile)
>  
>  # modpost option for external modules
>  MODPOST += -e
> -- 
> 2.37.2
> 

Does not apply to the 5.4.y tree at all, are you sure you generated this
properly?

thanks,

greg k-h