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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Wed, 29 Jun 2022 15:38:33 +0200
Message-ID: <CAJZ5v0jTz_-CKhX+W+ud5iVPprnx0Rp0YbEd4TOsZZ7i_psYnA@mail.gmail.com>
Subject: Re: [PATCH] hisi_lpc: Use acpi_dev_for_each_child()
To:     John Garry <john.garry@huawei.com>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Linux ACPI <linux-acpi@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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On Wed, Jun 29, 2022 at 3:34 PM John Garry <john.garry@huawei.com> wrote:
>
> On 29/06/2022 13:55, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > Instead of walking the list of children of an ACPI device directly,
> > use acpi_dev_for_each_child() to carry out an action for all of
> > the given ACPI device's children.
> >
> > This will help to eliminate the children list head from struct
> > acpi_device as it is redundant and it is used in questionable ways
> > in some places (in particular, locking is needed for walking the
> > list pointed to it safely, but it is often missing).
> >
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Hi Rafael,
>
> > ---
> >   drivers/bus/hisi_lpc.c |   12 ++++++++----
> >   1 file changed, 8 insertions(+), 4 deletions(-)
> >
> > Index: linux-pm/drivers/bus/hisi_lpc.c
> > ===================================================================
> > --- linux-pm.orig/drivers/bus/hisi_lpc.c
> > +++ linux-pm/drivers/bus/hisi_lpc.c
> > @@ -471,6 +471,12 @@ static int hisi_lpc_acpi_remove_subdev(s
> >       return 0;
> >   }
> >
> > +static int hisi_lpc_acpi_clear_enumerated(struct acpi_device *adev, void *not_used)
> > +{
> > +     acpi_device_clear_enumerated(adev);
> > +     return 0;
> > +}
> > +
> >   struct hisi_lpc_acpi_cell {
> >       const char *hid;
> >       const char *name;
> > @@ -480,13 +486,11 @@ struct hisi_lpc_acpi_cell {
> >
> >   static void hisi_lpc_acpi_remove(struct device *hostdev)
> >   {
> > -     struct acpi_device *adev = ACPI_COMPANION(hostdev);
> >       struct acpi_device *child;
> >
> I got this warn:
>
> drivers/bus/hisi_lpc.c: In function ‘hisi_lpc_acpi_remove’:
> drivers/bus/hisi_lpc.c:489:22: warning: unused variable ‘child’
> [-Wunused-variable]
>   489 |  struct acpi_device *child;
>       |                      ^~~~~
>   CC      drivers/bus/brcmstb_gisb.

I've overlooked that, sorry.  Will send a v2 fixing this shortly.

> With that fixed:
>
> Acked-by: John Garry <john.garry@huawei.com>

Thanks!

> Can you route this through one of your trees?

Yes, I will do that.