On Wed, 24 Nov 2021 08:29:40 +0100 Arnd Bergmann <arnd@xxxxxxxx> wrote: > On Tue, Nov 23, 2021 at 11:11 PM Paul Cercueil <paul@xxxxxxxxxxxxxxx> wrote: > > > > One word about the pm_ptr() macro. Right now it's defined as: > > #ifdef CONFIG_PM > > #define pm_ptr(_ptr) (_ptr) > > #else > > #define pm_ptr(_ptr) NULL > > #endif > > > > It could be possible to define it like this instead: > > #define pm_ptr(_ptr) PTR_IF(IS_ENABLED(CONFIG_PM), (_ptr)) > > > > The difference is that if !CONFIG_PM, in the first case the (_ptr) is > > not visible by the compiler and the __maybe_unused is required, while > > in the second case the (_ptr) is always visible by the compiler, but > > discarded as dead code. The reason we'd want that is the same reason we > > use IS_ENABLED() instead of macro guards; and you wouldn't need the > > __maybe_unused attribute anywhere. > > That sounds like a great idea. I see there are only 12 users of pm_ptr at > the moment, so auditing all of these should not be a problem. > > I gave it a brief look and found that we probably only need to fix > drivers/net/ethernet/realtek/r8169_main.c if we change the definition. Cool. > > > The problem then is that the SET_*_PM_OPS macros are defined > > differently according to CONFIG_PM, so their definition would need to > > be changed to use the (redefined) pm_ptr() macro and a corresponding > > pm_sleep_ptr() macro. Unfortunately since the SET_*_PM_OPS macros are > > used everywhere with code wrapped around #ifdef CONFIG_PM guards, it > > wouldn't be easy to change them, and it would just be easier to > > introduce new macros. > > Right, this is what we've discussed multiple times, and I think everyone > agreed we should do this, but so far we could not come up with a name > for the new macro, and changing the macro in place is not practical unless > we change hundreds of drivers in the same way as the iio series first. Nasty indeed and I'm not sure how scriptable either as lots of subtle variants unfortunately. I'm cynical - don't need a good name. *_OPS2 works fine for me as long as the docs are good. Jonathan > > Arnd
