linux-kernel - Re: [PATCH 6/6] kconfig: hide irrelevant menu for oldconfig

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Date:   Fri, 12 Jan 2018 17:23:34 +0100
From:   Ulf Magnusson <ulfalizer@...il.com>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        Sam Ravnborg <sam@...nborg.org>,
        Michal Marek <michal.lkml@...kovi.net>,
        Marc Herbert <marc.herbert@...el.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 6/6] kconfig: hide irrelevant menu for oldconfig

On Wed, Jan 10, 2018 at 7:56 AM, Masahiro Yamada
<yamada.masahiro@...ionext.com> wrote:
> Historically, "make oldconfig" has changed its behavior several times,
> quieter or louder.  (I attached the history below.)  Currently, it is
> not as quiet as it should be.  This commit addresses it.
>
>   Test Case
>   ---------
>
> ---------------------------(Kconfig)----------------------------
> menu "menu"
>
> config FOO
>         bool "foo"
>
> menu "sub menu"
>
> config BAR
>         bool "bar"
>
> endmenu
>
> endmenu
>
> menu "sibling menu"
>
> config BAZ
>         bool "baz"
>
> endmenu
> ----------------------------------------------------------------
>
> ---------------------------(.config)----------------------------
> CONFIG_BAR=y
> CONFIG_BAZ=y
> ----------------------------------------------------------------
>
> With the Kconfig and .config above, "make silentoldconfig" and
> "make oldconfig" work differently as follows:
>
>   $ make silentoldconfig
>   scripts/kconfig/conf  --silentoldconfig Kconfig
>   *
>   * Restart config...
>   *
>   *
>   * menu
>   *
>   foo (FOO) [N/y] (NEW) y
>   #
>   # configuration written to .config
>   #
>
>   $ make oldconfig
>   scripts/kconfig/conf  --oldconfig Kconfig
>   *
>   * Restart config...
>   *
>   *
>   * menu
>   *
>   foo (FOO) [N/y] (NEW) y
>   *
>   * sub menu
>   *
>   bar (BAR) [Y/n] y
>   #
>   # configuration written to .config
>   #
>
> Both hide "sibling node" since it is irrelevant.  The difference is
> that silentoldconfig hides "sub menu" whereas oldconfig does not.
> The behavior of silentoldconfig is preferred since the "sub menu"
> does not contain any new symbol.
>
> The root cause is in conf().  There are three input modes that can
> call conf(); oldaskconfig, oldconfig, and silentoldconfig.
>
> Everytime conf() encounters a menu entry, it calls check_conf() to
> check if it contains new symbols.  If no new symbol is found, the
> menu is just skipped.
>
> Currently, this happens only when input_mode == silentoldconfig.
> The oldaskconfig enters into the check_conf() loop as silentoldconfig,
> so oldaskconfig works likewise for the second loop or later, but it
> never happens for oldconfig.  So, irrelevant sub-menus are shown for
> oldconfig.
>
> Change the test condition to "input_mode != oldaskconfig".  This is
> false only for the first loop of oldaskconfig; it must ask the user
> all symbols, so no need to call check_conf().
>
>   History of oldconfig
>   --------------------
>
> [0] Originally, "make oldconfig" was as loud as "make config"  (It
>     showed the entire .config file)
>
> [1] Commit cd9140e1e73a ("kconfig: make oldconfig is now less chatty")
>     made oldconfig quieter, but it was still less quieter than
>     silentoldconfig.  (oldconfig did not hide sub-menus)
>
> [2] Commit 204c96f60904 ("kconfig: fix silentoldconfig") changed
>     the input_mode of oldconfig to "ask_silent" from "ask_new".
>     So, oldconfig really became as quiet as silentoldconfig.
>     (oldconfig hided irrelevant sub-menus)
>
> [3] Commit 4062f1a4c030 ("kconfig: use long options in conf") made
>     oldconfig as loud as [0] due to misconversion.
>
> [4] Commit 14828349719a ("kconfig: fix make oldconfig") addressed
>     the misconversion of [3], but it made oldconfig quieter only to
>     the same level as [1], not [2].
>
> This commit is restoring the behavior of [2].
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
> ---
>
>  scripts/kconfig/conf.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
> index 1d2ed3e..8b9cdf4 100644
> --- a/scripts/kconfig/conf.c
> +++ b/scripts/kconfig/conf.c
> @@ -368,8 +368,7 @@ static void conf(struct menu *menu)
>
>                 switch (prop->type) {
>                 case P_MENU:
> -                       if (input_mode == silentoldconfig &&
> -                           rootEntry != menu) {
> +                       if (input_mode != oldaskconfig && rootEntry != menu) {
>                                 check_conf(menu);
>                                 return;
>                         }
> @@ -660,7 +659,7 @@ int main(int ac, char **av)
>         case oldaskconfig:
>                 rootEntry = &rootmenu;
>                 conf(&rootmenu);
> -               input_mode = silentoldconfig;
> +               input_mode = oldconfig;
>                 /* fall through */
>         case oldconfig:
>         case listnewconfig:
> --
> 2.7.4
>

Looks good to me.

Maybe a comment along the following lines would be nice for
check_conf() as well:

/*
 * Recursively process modifiable symbols (and choices) in 'menu' that don't
 * have a user value
 */

check_conf() could be renamed to something like
process_new_modifiable_syms() as well.

The check_conf() call in conf() could have this above it as well:

/*
 * Except in oldaskconfig mode, we're only interested in new modifiable symbols
 */

Acked-by: Ulf Magnusson <ulfalizer@...il.com>

Cheers,
Ulf