Re: [PATCH 0/5] kbuild: allow big modules to sub-divide Makefiles

From: Sam Ravnborg
Date: Sat Aug 10 2019 - 02:54:06 EST

Hi Masahiro

On Tue, Aug 06, 2019 at 03:39:18PM +0900, Masahiro Yamada wrote:
> Recently, Jani Nikula requests a better build system support
> for drivers spanning multiple directories.
> (better kbuild support for drivers spanning multiple directories?)
> I implemented it, so please take a look at it.
> Note:
> The single targets do not work correctly.
> The single targets have never worked correctly:

It works in most cases, but now always.
I dunno how much it is used.
Myself I almost always do make /drivers/foo/bar/
> [1] For instance, "make drivers/foo/bar/baz.o" will descend into
> drivers/foo/bar/Makefile, which may not necessarily specify
> the build rule of baz.o
> It is possible for drivers/foo/Makefile having
> obj-$(CONFIG_BAZ) += bar/baz.o
> [2] subdir-ccflags-y does not work.
> The single targets directly descend into the directory of
> that file resides.
> It missed subdir-ccflags-y if it is specifies in parent
> Makefiles.
> Perhaps, I will have to manage correct implementation of single targets.
The day that kbuild has a separate step to read all Makefiles
and then without using recursive make can build the kernel we can have
this fixed.
Until then we can accpet it as is - as fixing this may not be simple.