| Message ID | 20170222150833.83149-1-richard.weiyang@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Wei, 2017-02-23 0:08 GMT+09:00 Wei Yang <richard.weiyang@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.weiyang@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))
On Sat, Mar 11, 2017 at 10:34:50PM +0900, Masahiro Yamada wrote: >Hi Wei, > > >2017-02-23 0:08 GMT+09:00 Wei Yang <richard.weiyang@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.weiyang@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. > Hi, Masahiro Thanks for your comment. Got your point, you are right. > > >Maybe adding the following should be enough? > >KBUILD_EXTMOD := $(patsubst %/,%,$(KBUILD_EXTMOD)) > Yep, it looks good. BTW, I found another interesting thing. make M=dir//// is also a valid target in kbuild. Even this is a very rare case, I plan to use this to handle it. KBUILD_EXTMOD := $(subst $(CURDIR)/,,$(KBUILD_EXTMOD)) This also works for an out tree build. I would send out v2 soon, hope you like this. > >-- >Best Regards >Masahiro Yamada
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
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.weiyang@gmail.com> --- Makefile | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)