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From:   "Rafael J. Wysocki" <rafael@kernel.org>
Date:   Fri, 10 Jun 2022 15:14:34 +0200
Message-ID: <CAJZ5v0gPyxRpJ9PTsnBJcY7mf5K7uEoaU+rubc1SPJHwhFWgDQ@mail.gmail.com>
Subject: Re: [PATCH v1 05/16] USB: ACPI: Use acpi_find_child_by_adr()
To:     Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Linux ACPI <linux-acpi@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux PM <linux-pm@vger.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "open list:ULTRA-WIDEBAND (UWB) SUBSYSTEM:" 
        <linux-usb@vger.kernel.org>
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Precedence: bulk

On Fri, Jun 10, 2022 at 8:47 AM Heikki Krogerus
<heikki.krogerus@linux.intel.com> wrote:
>
> On Thu, Jun 09, 2022 at 03:56:42PM +0200, 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
> > in order to find the child matching a given bus address, use
> > acpi_find_child_by_adr() for this purpose.
> >
> > Apart from simplifying the code, 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>
> > ---
> >  drivers/usb/core/usb-acpi.c |    9 +--------
> >  1 file changed, 1 insertion(+), 8 deletions(-)
> >
> > Index: linux-pm/drivers/usb/core/usb-acpi.c
> > ===================================================================
> > --- linux-pm.orig/drivers/usb/core/usb-acpi.c
> > +++ linux-pm/drivers/usb/core/usb-acpi.c
> > @@ -127,17 +127,10 @@ out:
> >  static struct acpi_device *usb_acpi_find_port(struct acpi_device *parent,
> >                                             int raw)
> >  {
> > -     struct acpi_device *adev;
> > -
> >       if (!parent)
> >               return NULL;
> >
> > -     list_for_each_entry(adev, &parent->children, node) {
> > -             if (acpi_device_adr(adev) == raw)
> > -                     return adev;
> > -     }
> > -
> > -     return acpi_find_child_device(parent, raw, false);
> > +     return acpi_find_child_by_adr(parent, raw);
> >  }
> >
> >  static struct acpi_device *
>
> I think usb_acpi_find_port() can also be dropped now.

Yes, it can.

I'm dropping it in the new version of the patch to be posted.