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| author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2018-02-28 20:17:37 +0100 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2018-03-05 23:48:29 +0900 |
| commit | 638e69cf2230737655fcb5ee9879c2fab7679187 (patch) | |
| tree | 09ea3453999ea8693a09aaa28aa0c94bf45f6ae8 /scripts/basic | |
| parent | 5b8ad96d1a4421ffe417e647a65064aad1e84fb4 (diff) | |
| download | linux-638e69cf2230737655fcb5ee9879c2fab7679187.tar.gz linux-638e69cf2230737655fcb5ee9879c2fab7679187.tar.bz2 linux-638e69cf2230737655fcb5ee9879c2fab7679187.zip | |
fixdep: do not ignore kconfig.h
kconfig.h was excluded from consideration by fixdep by
6a5be57f0f00 (fixdep: fix extraneous dependencies) to avoid some false
positive hits
(1) include/config/.h
(2) include/config/h.h
(3) include/config/foo.h
(1) occurred because kconfig.h contains the string CONFIG_ in a
comment. However, since dee81e988674 (fixdep: faster CONFIG_ search), we
have a check that the part after CONFIG_ is non-empty, so this does not
happen anymore (and CONFIG_ appears by itself elsewhere, so that check
is worthwhile).
(2) comes from the include guard, __LINUX_KCONFIG_H. But with the
previous patch, we no longer match that either.
That leaves (3), which amounts to one [1] false dependency (aka stat() call
done by make), which I think we can live with:
We've already had one case [2] where the lack of include/linux/kconfig.h in
the .o.cmd file caused a missing rebuild, and while I originally thought
we should just put kconfig.h in the dependency list without parsing it
for the CONFIG_ pattern, we actually do have some real CONFIG_ symbols
mentioned in it, and one can imagine some translation unit that just
does '#ifdef __BIG_ENDIAN' but doesn't through some other header
actually depend on CONFIG_CPU_BIG_ENDIAN - so changing the target
endianness could end up rebuilding the world, minus that small
TU. Quoting Linus,
... when missing dependencies cause a missed re-compile, the resulting
bugs can be _really_ subtle.
[1] well, two, we now also have CONFIG_BOOGER/booger.h - we could change
that to FOO if we care
[2] https://lkml.org/lkml/2018/2/22/838
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'scripts/basic')
| -rw-r--r-- | scripts/basic/fixdep.c | 1 |
1 files changed, 0 insertions, 1 deletions
diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c index 1b21870d6e7f..449b68c4c90c 100644 --- a/scripts/basic/fixdep.c +++ b/scripts/basic/fixdep.c @@ -283,7 +283,6 @@ static int is_ignored_file(const char *s, int len) { return str_ends_with(s, len, "include/generated/autoconf.h") || str_ends_with(s, len, "include/generated/autoksyms.h") || - str_ends_with(s, len, "include/linux/kconfig.h") || str_ends_with(s, len, ".ver"); } |