Subject: Re: [PATCH 2/8] ACPI: PM: Use the new device_to_pm() helper to access struct dev_pm_ops

From: Pavel Machek <[email-masked]>
Date: Tue, 26 May 2020 11:45:18 +0200

On Tue 2020-05-26 10:37:36, Rafael J. Wysocki wrote:
> On Mon, May 25, 2020 at 8:26 PM Krzysztof Wilczyński <[email-masked]> wrote:
> >
> > Use the new device_to_pm() helper to access Power Management callbacs
> > (struct dev_pm_ops) for a particular device (struct device_driver).
> >
> > No functional change intended.
> >
> > Signed-off-by: Krzysztof Wilczyński <[email-masked]>
> > ---
> >  drivers/acpi/device_pm.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
> > index 5832bc10aca8..b98a32c48fbe 100644
> > --- a/drivers/acpi/device_pm.c
> > +++ b/drivers/acpi/device_pm.c
> > @@ -1022,9 +1022,10 @@ static bool acpi_dev_needs_resume(struct device *dev, struct acpi_device *adev)
> >  int acpi_subsys_prepare(struct device *dev)
> >  {
> >         struct acpi_device *adev = ACPI_COMPANION(dev);
> > +       const struct dev_pm_ops *pm = driver_to_pm(dev->driver);
> 
> I don't really see a reason for this change.
> 
> What's wrong with the check below?

Duplicated code. Yes, compiler can sort it out, but... new version
looks better to me.

Best regards,
								pavel

> >
> > -       if (dev->driver && dev->driver->pm && dev->driver->pm->prepare) {
> > -               int ret = dev->driver->pm->prepare(dev);
> > +       if (pm && pm->prepare) {
> > +               int ret = pm->prepare(dev);

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