2018-02-19 8:45 GMT+09:00 Ulf Magnusson <ulfalizer@xxxxxxxxx>: > On Mon, Feb 19, 2018 at 12:37 AM, Masahiro Yamada > <yamada.masahiro@xxxxxxxxxxxxx> wrote: >> 2018-02-13 16:58 GMT+09:00 Ulf Magnusson <ulfalizer@xxxxxxxxx>: >>> The comment above the silentoldconfig invocation is outdated. >>> 'make oldconfig' updates just .config and doesn't touch the >>> include/config/ tree. >>> >>> This came up in https://lkml.org/lkml/2018/2/12/415. >>> >>> While fixing the comment, make it more informative by explaining the >>> purpose of the unfortunately named silentoldconfig. >>> >>> I can't make sense of the comment re. auto.conf.cmd and a cleaned tree. >>> include/config/auto.conf and include/config/auto.conf.cmd are both >>> created simultaneously by silentoldconfig (in >>> scripts/kconfig/confdata.c, by conf_write_autoconf()), and nothing seems >>> to remove auto.conf.cmd that wouldn't remove auto.conf. Remove that part >>> of the comment rather than blindly copying it. It might be a leftover >>> from an older way of doing things. >>> >>> The include/config/auto.conf.cmd prerequisite might be there to ensure >>> that silentoldconfig gets rerun if conf_write_autoconf() fails between >>> writing out auto.conf.cmd and auto.conf (a comment in the function >>> indicates that auto.conf is deliberately written out last to mark >>> completion of the operation). It seems the Makefile dependency between >>> include/config/auto.conf and .config would already take care of that >>> though, since include/config/auto.conf would still be out of date re. >>> .config if the operation fails. >>> >>> Cop out and leave the prerequisite in for now. >>> >>> Signed-off-by: Ulf Magnusson <ulfalizer@xxxxxxxxx> >>> --- >>> Changes in v2: >>> include/config/auto.conf depends on .config, not the other way around, so swap >>> them in some places in the commit message to make it less confusing. >>> >>> Makefile | 11 +++++++---- >>> 1 file changed, 7 insertions(+), 4 deletions(-) >>> >>> diff --git a/Makefile b/Makefile >>> index 79ad2bfa24b6..61ed99ad4b1b 100644 >>> --- a/Makefile >>> +++ b/Makefile >>> @@ -579,10 +579,13 @@ ifeq ($(KBUILD_EXTMOD),) >>> # To avoid any implicit rule to kick in, define an empty command >>> $(KCONFIG_CONFIG) include/config/auto.conf.cmd: ; >>> >>> -# If .config is newer than include/config/auto.conf, someone tinkered >>> -# with it and forgot to run make oldconfig. >>> -# if auto.conf.cmd is missing then we are probably in a cleaned tree so >>> -# we execute the config step to be sure to catch updated Kconfig files >>> +# The actual configuration files used during the build are stored in >>> +# include/generated/ and include/config/. Update them if .config is newer than >>> +# include/config/auto.conf (which mirrors .config). >> >> >> Yes, the first paragraph perfectly explains the code. >> >> >>> +# The include/config/ tree manages dependencies between source files and >>> +# Kconfig symbols and lets us avoid doing a full rebuild whenever the >>> +# configuration is changed. See scripts/basic/fixdep.c >> >> Do you insist on this paragraph? >> >> I know silentoldconfig touches include/config/* for extra cleverness, >> but, to me, this looks unnecessary information to >> understand the following code. >> >>> include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd >>> $(Q)$(MAKE) -f $(srctree)/Makefile silentoldconfig >>> else > > I think it's information that many people digging into the Makefiles > to figure out how the build works would find helpful, and my test is > more "is it helpful?" than "does it minimally describe just this > code?" > > I'm not hardcore about it though. Remove it if you think it's > irrelevant or might become outdated. :) > > Cheers, > Ulf > -- > To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html Applied to linux-kbuild. I removed the second paragraph due to my preference of brief comments. :) -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
