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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Tue, 12 Dec 2023 08:11:38 +0100
Message-ID: <CAMj1kXEB6XajecjXe3oX2nagO8foajdwZ99SiC_dD8WBjr+93w@mail.gmail.com>
Subject: Re: [PATCH v9 4/6] efivarfs: automatically update super block flag
To:     Masahisa Kojima <masahisa.kojima@linaro.org>
Cc:     Jens Wiklander <jens.wiklander@linaro.org>,
        Jan Kiszka <jan.kiszka@siemens.com>,
        Sumit Garg <sumit.garg@linaro.org>,
        linux-kernel@vger.kernel.org, op-tee@lists.trustedfirmware.org,
        Ilias Apalodimas <ilias.apalodimas@linaro.org>,
        Johan Hovold <johan+linaro@kernel.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Heinrich Schuchardt <heinrich.schuchardt@canonical.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Jeremy Kerr <jk@ozlabs.org>, linux-efi@vger.kernel.org
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On Tue, 12 Dec 2023 at 06:39, Masahisa Kojima
<masahisa.kojima@linaro.org> wrote:
>
> Hi Ard,
>
> On Mon, 11 Dec 2023 at 19:02, Ard Biesheuvel <ardb@kernel.org> wrote:
> >
> > On Fri, 13 Oct 2023 at 09:47, Masahisa Kojima
> > <masahisa.kojima@linaro.org> wrote:
> > >
> > > efivar operation is updated when the tee_stmm_efi module is probed.
> > > tee_stmm_efi module supports SetVariable runtime service,
> > > but user needs to manually remount the efivarfs as RW to enable
> > > the write access if the previous efivar operation does not support
> > > SerVariable and efivarfs is mounted as read-only.
> > >
> > > This commit notifies the update of efivar operation to
> > > efivarfs subsystem, then drops SB_RDONLY flag if the efivar
> > > operation supports SetVariable.
> > >
> > > Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
> >
> > Unfortunately, I have identified a problem with this approach.
> >
> > There are cases where there are multiple instances of struct
> > superblock are associated with the efivarfs file system [0].
> >
> > So I reworked the patch a little - please take the time to double
> > check that I did not make any mistakes here.
> >
> > [0] https://lore.kernel.org/linux-efi/20231208163925.3225018-8-ardb@google.com/T/#u
>
> I think you are referring to this patch[1]?
> The modification should be OK, also I have tested it works as expected.
>
> Thank you very much for fixing this.
>

Thank you Masahisa.