On 24-03-21, 09:17, Jie Deng wrote:

I didn't see the "struct virtio_driver" has a member "struct dev_pm_ops *pm"

It defines its own hooks (freeze and restore) though it includes "struct
device_driver"

which has a "struct dev_pm_ops *pm".

I just follow other virtio drivers to directly use the hooks defined in
"struct virtio_driver".

Right, I think we can't use the SIMPLE PM OPS for virtio yet, the core calls
only the freeze and restore callbacks which are part of struct virtio_driver.

For this driver, Both __maybe_unused and #ifdef are OK to me.

Yes, and so you should use only #ifdef here as Arnd confirmed. You shouldn't be
using __maybe_unused as there is nothing confusing here related to the macros.

-- 
viresh