Hi Wei,
2017-02-23 0:08 GMT+09:00 Wei Yang <richard.weiy...@gmail.com>:
> Current kbuild will build the target again if we run "make M=dir" and "make
> M=dir/" by turns, since if_changed will see the prerequisite is changed.
> The behavior may confuse the user a little, since actually we are building
> the same target and no difference.
>
> According to current implementation in scripts/Makefile.build, the obj
> passed to next level is a directory name with last slash stripped. This
> patch strips the last slash in KBUILD_EXTMOD which is assigned from "M=".
>
> Signed-off-by: Wei Yang <richard.weiy...@gmail.com>
> ---
> Makefile | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index b1037774e8e8..db6ed60928ab 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -184,13 +184,15 @@ endif
> # Old syntax make ... SUBDIRS=$PWD is still supported
> # Setting the environment variable KBUILD_EXTMOD take precedence
> ifdef SUBDIRS
> - KBUILD_EXTMOD ?= $(SUBDIRS)
> + __KBUILD_EXTMOD ?= $(SUBDIRS)
> endif
>
> ifeq ("$(origin M)", "command line")
> - KBUILD_EXTMOD := $(M)
> + __KBUILD_EXTMOD := $(M)
> endif
>
> +KBUILD_EXTMOD = $(patsubst %/,%,$(__KBUILD_EXTMOD))
> +
> # If building an external module we do not care about the all: rule
> # but instead _all depend on modules
> PHONY += all
This patch would break a use-case
where KBUILD_EXTMOD is given as an environment.
Maybe adding the following should be enough?
KBUILD_EXTMOD := $(patsubst %/,%,$(KBUILD_EXTMOD))
--
Best Regards
Masahiro Yamada
