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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Mon, 11 Jul 2022 17:06:50 +0200
Message-ID: <CAK8P3a0Qo=xexUDs=XA2gRe4p-FPoXUpuxWrnqWrr43FTViA3w@mail.gmail.com>
Subject: Re: [PATCH 1/4] of: add struct page support to rmem
To:     Li Chen <me@linux.beauty>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Frank Rowand <frowand.list@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Li Chen <lchen@ambarella.com>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        DTML <devicetree@vger.kernel.org>, Linux-MM <linux-mm@kvack.org>
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On Mon, Jul 11, 2022 at 4:51 PM Li Chen <me@linux.beauty> wrote:
>  ---- On Mon, 11 Jul 2022 21:36:12 +0800  Arnd Bergmann <arnd@arndb.de> wrote ---
>  > On Mon, Jul 11, 2022 at 2:24 PM Li Chen <me@linux.beauty> wrote:
>  >
>  > > +config OF_RESERVED_MEM_DIO_SUPPORT
>  > > +       bool "add Direct I/O support to reserved_mem"
>  > > +       depends on ZONE_DEVICE && ARCH_KEEP_MEMBLOCK
>  > > +       help
>  > > +          By default, reserved memory don't get struct page support, which
>  > > +                means you cannot do Direct I/O from this region. This config takes
>  > > +                uses of ZONE_DEVICE and treats rmem as hotplug mem to get struct
>  > > +                page and DIO support.
>  >
>  > This probably does not need to be user visible, it's enough to select it from
>  > the drivers that need it.
>
> When you say "user visible", do you mean the config can be dropped or something else like Kconfig type other than bool?

I mean this can be a hidden option, which you can do by leaving out the
one-line description after the 'bool' keyword. The option will still
be selectable
in Kconfig files from other options, but not shown in 'make menuconfig'.

        Arnd