Re: [PATCH] virtio: pci: Use SIMPLE_DEV_PM_OPS macro

[Jingoo Han <jg1.han@samsung.com>]

On Tuesday, September 09, 2014 9:14 AM, Rusty Russell wrote:
> Jingoo Han <jg1.han@samsung.com> writes:
> > Use SIMPLE_DEV_PM_OPS macro in order to make the code simpler.
> >
> > Signed-off-by: Jingoo Han <jg1.han@samsung.com>
> 
> This patch is obviously wrong.  It won't compile without
> CONFIG_PM_SLEEP.

No, there is no compile issue.
When, CONFIG_PM_SLEEP=n, there is no build error.

'SIMPLE_DEV_PM_OPS' macro is defined as follows.

#define SIMPLE_DEV_PM_OPS(name, suspend_fn, resume_fn) \
const struct dev_pm_ops name = { \
        SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
}

In addition, 'SET_SYSTEM_SLEEP_PM_OPS' is defined as follows.

#ifdef CONFIG_PM_SLEEP
#define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \
        .suspend = suspend_fn, \
        .resume = resume_fn, \
        .freeze = suspend_fn, \
        .thaw = resume_fn, \
        .poweroff = suspend_fn, \
        .restore = resume_fn,
#else
#define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn)
#endif

So, when CONFIG_PM_SLEEP is NOT enabled, SIMPLE_DEV_PM_OPS can be
changed as below. The members of virtio_pci_pm_ops can be NULL.
Thus, there is no build error, when CONFIG_PM_SLEEP=n.

However, if you want, I will just change SET_SYSTEM_SLEEP_PM_OPS
into SIMPLE_DEV_PM_OPS macro, without any change about
'#ifdef CONFIG_PM_SLEEP' guards.

const struct dev_pm_ops virtio_pci_pm_ops = {
};

static struct pci_driver virtio_pci_driver = {
 	.name		= "virtio-pci",
 	.id_table	= virtio_pci_id_table,
 	.probe		= virtio_pci_probe,
 	.remove		= virtio_pci_remove,
 	.driver.pm	= &virtio_pci_pm_ops,
};

Best regards,
Jingoo Han

> 
> Cheers,
> Rusty.
> 
> > ---
> >  drivers/virtio/virtio_pci.c | 9 +++------
> >  1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
> > index 3d1463c6b120..c5fbdb4023d1 100644
> > --- a/drivers/virtio/virtio_pci.c
> > +++ b/drivers/virtio/virtio_pci.c
> > @@ -810,20 +810,17 @@ static int virtio_pci_restore(struct device *dev)
> >
> >  	return ret;
> >  }
> > -
> > -static const struct dev_pm_ops virtio_pci_pm_ops = {
> > -	SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore)
> > -};
> >  #endif
> >
> > +static SIMPLE_DEV_PM_OPS(virtio_pci_pm_ops, virtio_pci_freeze,
> > +			 virtio_pci_restore);
> > +
> >  static struct pci_driver virtio_pci_driver = {
> >  	.name		= "virtio-pci",
> >  	.id_table	= virtio_pci_id_table,
> >  	.probe		= virtio_pci_probe,
> >  	.remove		= virtio_pci_remove,
> > -#ifdef CONFIG_PM_SLEEP
> >  	.driver.pm	= &virtio_pci_pm_ops,
> > -#endif
> >  };
> >
> >  module_pci_driver(virtio_pci_driver);
> > --
> > 2.0.0