From 4e8fc3f55a38996a56106d6adfac72885ddd97ef Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Tue, 25 Jun 2019 17:51:27 +0900 Subject: [PATCH] kbuild: add more hints about SUBDIRS replacement Commit 0126be38d988 ("kbuild: announce removal of SUBDIRS if used") added a hint about the 'SUBDIRS' replacement, but it was not clear enough. Multiple people sent me similar questions, patches. For instance, https://lkml.org/lkml/2019/1/17/456 I did not mean to use M= for building a subdirectory in the kernel tree. From commit 669efc76b317 ("net: hns3: fix compile error"), people already (ab)use M=... to do that because it seems to work to some extent. Documentation/kbuild/kbuild.txt says M= and KBUILD_EXTMOD are used for building external modules. In fact, Kbuild supports the single target '%/' for this purpose, but this may not be noticed much. Kindly add more hints. Makefile:213: ================= WARNING ================ Makefile:214: 'SUBDIRS' will be removed after Linux 5.3 Makefile:215: Makefile:216: If you are building an individual subdirectory Makefile:217: in the kernel tree, you can do like this: Makefile:218: $ make path/to/dir/you/want/to/build/ Makefile:219: (Do not forget the trailing slash) Makefile:220: Makefile:221: If you are building an external module, Makefile:222: Please use 'M=' or 'KBUILD_EXTMOD' instead Makefile:223: ========================================== Suggested-by: Christoph Hellwig Signed-off-by: Masahiro Yamada Acked-by: Sam Ravnborg --- Makefile | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/Makefile b/Makefile index d6c3dba..eb850190 100644 --- a/Makefile +++ b/Makefile @@ -212,6 +212,13 @@ endif ifdef SUBDIRS $(warning ================= WARNING ================) $(warning 'SUBDIRS' will be removed after Linux 5.3) + $(warning ) + $(warning If you are building an individual subdirectory) + $(warning in the kernel tree, you can do like this:) + $(warning $$ make path/to/dir/you/want/to/build/) + $(warning (Do not forget the trailing slash)) + $(warning ) + $(warning If you are building an external module,) $(warning Please use 'M=' or 'KBUILD_EXTMOD' instead) $(warning ==========================================) KBUILD_EXTMOD ?= $(SUBDIRS) -- 2.7.4