Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <12036348.O9o76ZdvQC@kreacher> <2196460.iZASKD2KPV@kreacher> <5857822.lOV4Wx5bFT@kreacher>
In-Reply-To: <5857822.lOV4Wx5bFT@kreacher>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Wed, 24 Aug 2022 21:23:16 +0300
Message-ID: <CAHp75VcjxUjH4p_NOEQjOuFO8LcSdUU_stEvfWvtbQc8hfud0w@mail.gmail.com>
Subject: Re: [PATCH v2 5/5] ACPI: Drop parent field from struct acpi_device
To:     "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc:     Linux ACPI <linux-acpi@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Linux PM <linux-pm@vger.kernel.org>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Mark Brown <broonie@kernel.org>,
        Andreas Noever <andreas.noever@gmail.com>,
        Michael Jamet <michael.jamet@intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Yehezkel Bernat <YehezkelShB@gmail.com>,
        Linux on Hyper-V List <linux-hyperv@vger.kernel.org>,
        linux-spi <linux-spi@vger.kernel.org>,
        USB <linux-usb@vger.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Konrad Dybcio <konrad.dybcio@somainline.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Wed, Aug 24, 2022 at 8:13 PM Rafael J. Wysocki <rjw@rjwysocki.net> wrote:
>
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> The parent field in struct acpi_device is, in fact, redundant,
> because the dev.parent field in it effectively points to the same
> object and it is used by the driver core.
>
> Accordingly, the parent field can be dropped from struct acpi_device
> and for this purpose define acpi_dev_parent() to retrieve a parent
> struct acpi_device pointer from the dev.parent field in struct
> acpi_device.  Next, update all of the users of the parent field
> in struct acpi_device to use acpi_dev_parent() instead of it and
> drop it.
>
> While at it, drop the ACPI_IS_ROOT_DEVICE() macro that is only used
> in one place in a confusing way.
>
> No intentional functional impact.

Side note: Should we not convert these to use acpi_dev_parent()?

https://elixir.bootlin.com/linux/v6.0-rc2/source/drivers/acpi/property.c#L1271
https://elixir.bootlin.com/linux/v6.0-rc2/source/drivers/bus/hisi_lpc.c#L397

-- 
With Best Regards,
Andy Shevchenko