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From:   Lukas Bulwahn <lukas.bulwahn@gmail.com>
Date:   Wed, 28 Sep 2022 09:12:34 +0200
Message-ID: <CAKXUXMzbwKRBR2kPLcU7zXwyd8Krm8zevFFzWenr2RBWHdOLtw@mail.gmail.com>
Subject: Re: [PATCH -next] init/Kconfig: fix unmet direct dependencies
To:     Ren Zhijie <renzhijie2@huawei.com>
Cc:     akpm@linux-foundation.org, ndesaulniers@google.com,
        nathan@kernel.org, vbabka@suse.cz, masahiroy@kernel.org,
        arnd@arndb.de, bigeasy@linutronix.de, seanjc@google.com,
        hannes@cmpxchg.org, ojeda@kernel.org, mhiramat@kernel.org,
        dmitry.torokhov@gmail.com, atomlin@redhat.com, ddiss@suse.de,
        christophe.leroy@csgroup.eu, linux-kernel@vger.kernel.org
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Precedence: bulk

On Wed, Sep 28, 2022 at 8:53 AM Ren Zhijie <renzhijie2@huawei.com> wrote:
>
> Commit 3c07bfce92a5 ("proc: make config PROC_CHILDREN depend on PROC_FS")
> make config PROC_CHILDREN depend on PROC_FS.
>
> When CONFIG_PROC_FS is not set and CONFIG_CHECKPOINT_RESTORE=y,
> make menuconfig screams like this:
>
> WARNING: unmet direct dependencies detected for PROC_CHILDREN
>   Depends on [n]: PROC_FS [=n]
>   Selected by [y]:
>   - CHECKPOINT_RESTORE [=y]
>
> So add PROC_FS to dependencies to fix this.
> Fixes: 3c07bfce92a5 ("proc: make config PROC_CHILDREN depend on PROC_FS")
> Signed-off-by: Ren Zhijie <renzhijie2@huawei.com>

This patch here makes sense.

Just some minor addition:

The commit  3c07bfce92a5 ("proc: make config PROC_CHILDREN depend on
PROC_FS") is not really broken, but just made the implicit
dependencies much more explicit and hence now this warning from
menuconfig indicates that.

Before the commit 3c07bfce92a5 ("proc: make config PROC_CHILDREN
depend on PROC_FS"):

When CONFIG_PROC_FS is not set and CONFIG_CHECKPOINT_RESTORE=y, then
the feature of CONFIG_CHECKPOINT_RESTORE would just not worked (as
this would not be any proc fs, and no "proc children" functionality.)

After the commit 3c07bfce92a5 ("proc: make config PROC_CHILDREN depend
on PROC_FS"):

When CONFIG_PROC_FS is not set and CONFIG_CHECKPOINT_RESTORE=y, it
warns to add PROC_FS to assist in configuring something that makes the
feature of CONFIG_CHECKPOINT_RESTORE work.

So this patch is yet another improvement to what the commit
3c07bfce92a5 ("proc: make config PROC_CHILDREN depend on PROC_FS")
already partially improved. However, feel free to keep the Fixes-tag
in this patch, as this patch certainly improves handling of what the
commit 3c07bfce92a5 started improving.

Reviewed-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>

The recipient list is a bit "random" (coincidental). You could have
probably just sent this patch to Andrew Morton, me and linux-kernel
mailing list.

Lukas

> ---
>  init/Kconfig | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/init/Kconfig b/init/Kconfig
> index e11307310fc1..fc32b28fe93e 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1273,6 +1273,7 @@ endif # NAMESPACES
>
>  config CHECKPOINT_RESTORE
>         bool "Checkpoint/restore support"
> +       select PROC_FS
>         select PROC_CHILDREN
>         select KCMP
>         default n
> --
> 2.17.1
>