linux-kernel - Re: [PATCH v4] streamline_config.pl: add LMC

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Date:   Fri, 8 May 2020 22:00:47 +0800
From:   Changbin Du <changbin.du@...il.com>
To:     Steven Rostedt <rostedt@...dmis.org>
Cc:     Masahiro Yamada <masahiroy@...nel.org>,
        Changbin Du <changbin.du@...il.com>,
        Jonathan Corbet <corbet@....net>,
        "open list:DOCUMENTATION" <linux-doc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Randy Dunlap <rdunlap@...radead.org>
Subject: Re: [PATCH v4] streamline_config.pl: add LMC_KEEP to preserve some
 kconfigs

On Thu, May 07, 2020 at 09:18:07AM -0400, Steven Rostedt wrote:
> On Thu, 7 May 2020 12:19:57 +0900
> Masahiro Yamada <masahiroy@...nel.org> wrote:
> 
> > On Sun, May 3, 2020 at 9:11 AM Changbin Du <changbin.du@...il.com> wrote:
> > >
> > > Sometimes it is useful to preserve batches of configs when making
> > > localmodconfig. For example, I usually don't want any usb and fs
> > > modules to be disabled. Now we can do it by:
> > >
> > >  $ make LMC_KEEP="drivers/usb;fs" localmodconfig
> > >
> > > Signed-off-by: Changbin Du <changbin.du@...il.com>
> > >
> > > ---
> > > v4: fix typo.
> > > v3: rename LOCALMODCONFIG_PRESERVE to shorter LMC_KEEP.
> > > v2: fix typo in documentation. (Randy Dunlap)
> > > ---  
> > 
> > 
> > Personally, I do not mind the long LOCALMODCONFIG_PRESERVE,
> 
> Perhasp we allow both? ;-)
> 
> And just have one set to the other.
> 
> > but this tends to be bike-sheding.
> > I do not have a strong opinion.
> > 
> > 
> > >  Documentation/admin-guide/README.rst |  8 +++++++-
> > >  scripts/kconfig/Makefile             |  1 +
> > >  scripts/kconfig/streamline_config.pl | 23 +++++++++++++++++++++++
> > >  3 files changed, 31 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/Documentation/admin-guide/README.rst b/Documentation/admin-guide/README.rst
> > > index cc6151fc0845..1371deab8bc7 100644
> > > --- a/Documentation/admin-guide/README.rst
> > > +++ b/Documentation/admin-guide/README.rst
> > > @@ -209,10 +209,16 @@ Configuring the kernel
> > >                             store the lsmod of that machine into a file
> > >                             and pass it in as a LSMOD parameter.
> > >
> > > +                           Also, you can preserve modules in certain folders
> > > +                           or kconfig files by specifying their paths in
> > > +                           parameter LMC_KEEP.
> > > +
> > >                     target$ lsmod > /tmp/mylsmod
> > >                     target$ scp /tmp/mylsmod host:/tmp
> > >
> > > -                   host$ make LSMOD=/tmp/mylsmod localmodconfig
> > > +                   host$ make LSMOD=/tmp/mylsmod \
> > > +                           LMC_KEEP="drivers/usb;drivers/gpu;fs" \  
> > 
> > 
> > This might be another bike-sheding item, but
> > can you use a space for the delimiter?
> > 
> > 
> > LMC_KEEP="drivers/usb drivers/gpu fs"
> > 
> > If you pass multiple directories,
> > you will need to surround them with double-quotes.
> 
> I agree that spaces look better.
>
I am okay with space. But what about ":" which is used by shell PATH and many
others?

> > 
> > 
> > 
> > 
> > > +                           localmodconfig
> > >
> > >                             The above also works when cross compiling.
> > >
> > > diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
> > > index c9d0a4a8efb3..e0abbf5805f5 100644
> > > --- a/scripts/kconfig/Makefile
> > > +++ b/scripts/kconfig/Makefile
> > > @@ -123,6 +123,7 @@ help:
> > >         @echo  '  gconfig         - Update current config utilising a GTK+ based front-end'
> > >         @echo  '  oldconfig       - Update current config utilising a provided .config as base'
> > >         @echo  '  localmodconfig  - Update current config disabling modules not loaded'
> > > +       @echo  '                    except those preserved by LMC_KEEP environment variable'
> > >         @echo  '  localyesconfig  - Update current config converting local mods to core'
> > >         @echo  '  defconfig       - New config with default from ARCH supplied defconfig'
> > >         @echo  '  savedefconfig   - Save current config as ./defconfig (minimal config)'
> > > diff --git a/scripts/kconfig/streamline_config.pl b/scripts/kconfig/streamline_config.pl
> > > index e2f8504f5a2d..d26543a807c9 100755
> > > --- a/scripts/kconfig/streamline_config.pl
> > > +++ b/scripts/kconfig/streamline_config.pl
> > > @@ -143,6 +143,7 @@ my %depends;
> > >  my %selects;
> > >  my %prompts;
> > >  my %objects;
> > > +my %config2kfile;
> > >  my $var;
> > >  my $iflevel = 0;
> > >  my @ifdeps;
> > > @@ -201,6 +202,7 @@ sub read_kconfig {
> > >         if (/^\s*(menu)?config\s+(\S+)\s*$/) {
> > >             $state = "NEW";
> > >             $config = $2;
> > > +           $config2kfile{"CONFIG_$config"} = $kconfig;
> > >
> > >             # Add depends for 'if' nesting
> > >             for (my $i = 0; $i < $iflevel; $i++) {
> > > @@ -592,6 +594,22 @@ while ($repeat) {
> > >
> > >  my %setconfigs;
> > >
> > > +my @preserved_kconfigs;
> > > +@...served_kconfigs = split(/;/,$ENV{LMC_KEEP}) if (defined($ENV{LMC_KEEP}));  
> > 
> > Maybe, you can do 'my' declaration and the assignment
> > in a single line?
> > 
> > Can you drop the 'if ...' conditional?
> > 
> > 
> > Does this work for you?
> > 
> > my @preserved_kconfigs = split(/;/,$ENV{LMC_KEEP});
> > 
> > 
> 
> Will an undefined warning happen if LMC_KEEP isn't defined?
> 
I just verifed there is no warning raised.

> -- Steve

-- 
Cheers,
Changbin Du