From 2dffd23f81a365307c0edcf9cb40b6ddae2b481e Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <yamada.masahiro@socionext.com>
Date: Wed, 16 Oct 2019 14:15:47 +0900
Subject: [PATCH] kbuild: make single target builds much faster
Since commit 394053f4a4b3 ("kbuild: make single targets work more
correctly"), building single targets is really slow.
Speed it up by not descending into unrelated directories.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---
scripts/Makefile.build | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index dcbb0124dac48..7eabbb66a65c0 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -479,7 +479,10 @@ curdir-single := $(sort $(foreach x, $(KBUILD_SINGLE_TARGETS), \
unknown-single := $(filter-out $(addsuffix /%, $(subdir-ym)), \
$(filter-out $(curdir-single), $(KBUILD_SINGLE_TARGETS)))
-__build: $(curdir-single) $(subdir-ym)
+single-subdirs := $(foreach d, $(subdir-ym), \
+ $(if $(filter $(d)/%, $(KBUILD_SINGLE_TARGETS)), $(d)))
+
+__build: $(curdir-single) $(single-subdirs)
ifneq ($(unknown-single),)
$(Q)$(MAKE) -f /dev/null $(unknown-single)
endif
--
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