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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Wed, 17 Nov 2021 15:45:34 +0100
Message-ID: <CAJZ5v0if7__bYSnNWYNd7c9MfG32Sm2_cRcw6Qr+C2t2ywE-tg@mail.gmail.com>
Subject: Re: [RFC PATCH] software node: Skip duplicated software_node sysfs
To:     Qian Cai <quic_qiancai@quicinc.com>
Cc:     "Rafael J. Wysocki" <rafael@kernel.org>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Wed, Nov 17, 2021 at 3:38 PM Qian Cai <quic_qiancai@quicinc.com> wrote:
>
> On Tue, Nov 16, 2021 at 05:29:56PM +0100, Rafael J. Wysocki wrote:
> > > Frist, fixes all dev->fwnode / dev.fwnode to use dev_fwnode(). This
> > > could be a standalone tree-wide patchset going out to avoid
> > > heavy-lifting later.
> > >
> > > Then, we can create another patchset on top. I have audited
> > > "irq_domain" but not seen any "secondary" leakage. Struct
> > > "cht_int33fe_data" does have some need to fix.
> > >
> > > Rename set_secondary_fwnode() to insert_secondary_fwnode(). Fix things
> > > in drivers/base/core.c, swnode.c etc to use the new fwnode_head and
> > > anything I can't think of right now.
> > >
> > > Since we will have multiple "software_node" (secondary fwnode:s) for a
> > > single "device". What would be the usual way to deal with a
> > > linked-list in the sysfs? I can think of just let "software_node"
> > > become a directory to host a list of symlinks named from
> > > swnode->id. Thoughts?
> >
> > Note that one pointer dereference in ACPI_COMPANION() is enough.
>
> Rafael, we suppose to convert ACPI_COMPANION() to:
>
> to_acpi_device_node(dev_fwnode())
>
> since we will no longer has a dev->fwnode pointer anymore. Do you
> suggest to keep that pointer but convert the "secondary" to a linked
> list instead?

Yes, please.