Re: [PATCH] Drivers: hv: vmbus: Fix harmless building warnings without CONFIG_PM

[Arnd Bergmann]

On Thu, Sep 19, 2019 at 11:38 PM Dexuan Cui <decui@xxxxxxxxxxxxx> wrote:
> > Sent: Thursday, September 19, 2019 5:11 AM
> > On Thu, Sep 19, 2019 at 7:19 AM Dexuan Cui <decui@xxxxxxxxxxxxx> wrote:

> > I think this will still produce a warning if CONFIG_PM is set but
> > CONFIG_PM_SLEEP is not, possibly in other configurations as
> > well.
>
> You're correct. Thanks!
>
> I'll use " #ifdef CONFIG_PM_SLEEP ... #endif" instead.
>
> The mentioned functions are only used in the micros
> SET_NOIRQ_SYSTEM_SLEEP_PM_OPS, which is empty if CONFIG_PM_SLEEP
> is not defined. So it looks to me using "#ifdef CONFIG_PM_SLEEP ..." should
> resolve the issue.

Probably, yes. There are sometimes surprising effects, such as when one of the
functions inside of the #ifdef call another function that is otherwise unused.

I would normally try to build a few hundred randconfig builds to be fairly sure
of a change like this, or use __maybe_unused like most other drivers do here.

       Arnd