Messages in this thread | | | From | Stephen Zhang <> | Date | Fri, 22 Sep 2023 10:01:36 +0800 | Subject | Re: [PATCH] mfd: cs42l43: fix defined but not used warnings |
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Lee Jones <lee@kernel.org> 于2023年9月21日周四 18:37写道: > > On Thu, 21 Sep 2023, Stephen Zhang wrote: > > > Lee Jones <lee@kernel.org> 于2023年9月20日周三 17:52写道: > > > > > > On Tue, 05 Sep 2023, zhangshida wrote: > > > > > > > From: Shida Zhang <zhangshida@kylinos.cn> > > > > > > > > Warnings were generated during compiling for functions like > > > > cs42l43_*_{resume,suspend}: > > > > > > > > ../drivers/mfd/cs42l43.c:1138:12: error: ‘cs42l43_runtime_resume’ defined but not used [-Werror=unused-function] > > > > 1138 | static int cs42l43_runtime_resume(struct device *dev) > > > > | ^~~~~~~~~~~~~~~~~~~~~~ > > > > ../drivers/mfd/cs42l43.c:1124:12: error: ‘cs42l43_runtime_suspend’ defined but not used [-Werror=unused-function] > > > > 1124 | static int cs42l43_runtime_suspend(struct device *dev) > > > > | ^~~~~~~~~~~~~~~~~~~~~~~ > > > > ../drivers/mfd/cs42l43.c:1106:12: error: ‘cs42l43_resume’ defined but not used [-Werror=unused-function] > > > > 1106 | static int cs42l43_resume(struct device *dev) > > > > | ^~~~~~~~~~~~~~ > > > > ../drivers/mfd/cs42l43.c:1076:12: error: ‘cs42l43_suspend’ defined but not used [-Werror=unused-function] > > > > 1076 | static int cs42l43_suspend(struct device *dev) > > > > > > > > Fix it by guarding it with CONFIG_PM/CONFIG_PM_SLEEP. > > > > > > > > Reported-by: k2ci <kernel-bot@kylinos.cn> > > > > Signed-off-by: Shida Zhang <zhangshida@kylinos.cn> > > > > --- > > > > drivers/mfd/cs42l43.c | 4 ++++ > > > > 1 file changed, 4 insertions(+) > > > > > > > > diff --git a/drivers/mfd/cs42l43.c b/drivers/mfd/cs42l43.c > > > > index 37b23e9bae82..e589a61c118d 100644 > > > > --- a/drivers/mfd/cs42l43.c > > > > +++ b/drivers/mfd/cs42l43.c > > > > @@ -1073,6 +1073,7 @@ void cs42l43_dev_remove(struct cs42l43 *cs42l43) > > > > } > > > > EXPORT_SYMBOL_NS_GPL(cs42l43_dev_remove, MFD_CS42L43); > > > > > > > > +#ifdef CONFIG_PM_SLEEP > > > > static int cs42l43_suspend(struct device *dev) > > > > { > > > > struct cs42l43 *cs42l43 = dev_get_drvdata(dev); > > > > @@ -1120,7 +1121,9 @@ static int cs42l43_resume(struct device *dev) > > > > > > > > return 0; > > > > } > > > > +#endif > > > > > > > > +#ifdef CONFIG_PM > > > > static int cs42l43_runtime_suspend(struct device *dev) > > > > { > > > > struct cs42l43 *cs42l43 = dev_get_drvdata(dev); > > > > @@ -1176,6 +1179,7 @@ static int cs42l43_runtime_resume(struct device *dev) > > > > > > > > return ret; > > > > } > > > > +#endif > > > > > > > > EXPORT_NS_GPL_DEV_PM_OPS(cs42l43_pm_ops, MFD_CS42L43) = { > > > > SET_SYSTEM_SLEEP_PM_OPS(cs42l43_suspend, cs42l43_resume) > > > > > > I see a bunch of drivers using PM helpers and not many of them are > > > are being guarded by ugly #ifery. Please find out what they're doing to > > > solve the same issue and replicate that instead. > > > > > > Here's a really big hint: > > > > > > `git log --oneline 02313a90095fb` > > > > > > > Thanks, I've learned something from the hint. > > > > And I also checked the code: > > ----- > > EXPORT_NS_GPL_DEV_PM_OPS(cs42l43_pm_ops, MFD_CS42L43) = { > > SET_SYSTEM_SLEEP_PM_OPS(cs42l43_suspend, cs42l43_resume) > > SET_RUNTIME_PM_OPS(cs42l43_runtime_suspend, > > cs42l43_runtime_resume, NULL) > > }; > > ---- > > #ifdef CONFIG_PM_SLEEP > > #define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \ > > SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) > > #else > > #define SET_SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) > > #endif > > ---- > > #define SYSTEM_SLEEP_PM_OPS(suspend_fn, resume_fn) \ > > .suspend = pm_sleep_ptr(suspend_fn), \ > > .resume = pm_sleep_ptr(resume_fn), \ > > .freeze = pm_sleep_ptr(suspend_fn), \ > > .thaw = pm_sleep_ptr(resume_fn), \ > > .poweroff = pm_sleep_ptr(suspend_fn), \ > > .restore = pm_sleep_ptr(resume_fn), > > ---- > > The technique has already been used by the marcos, but it still > > reports the defined-but-not-used warning. > > The MACROS can use #ifery since they are located in header files. > > #ifery in C files is to be avoided if at all possible. > > > Maybe some compilers still choose to compile these functions in... > > Anyway, I will just leave it alone since it is really not a big problem... > > If you're seeing an error, it should be fixed.
<nod>
> > Why is this not an issue anywhere else? > > Does the same build complain about all the other drivers too? >
Nope, at least 88pm860x-core.c is good: ---- drivers/mfd/88pm860x-core.c static int pm860x_suspend(struct device *dev) static DEFINE_SIMPLE_DEV_PM_OPS(pm860x_pm_ops, pm860x_suspend, pm860x_resume); static struct i2c_driver pm860x_driver = { .driver = { .name = "88PM860x", .pm = pm_sleep_ptr(&pm860x_pm_ops), .of_match_table = pm860x_dt_ids, }, .probe_new = pm860x_probe, ---- ... LD [M] sound/pci/echoaudio/snd-layla20.o CC drivers/mfd/88pm860x-core.o CC drivers/misc/eeprom/max6875.o CC arch/mips/vdso/vdso-image.o ... ----
It is generated by mips-linux-gnu-gcc, which always exhibits some peculiar behavior.
Since it reports 'defined but not used,' it implies that the macro successfully removed any usage of 'cs42l43_*.' However, the compiler still chose not to optimize these functions out. It's very weird. Maybe the problem comes from the optimization process in mips compiler?
I will attach the kernel.config and the build.log for your reference.
> -- > Lee Jones [李琼斯] [unhandled content-type:application/octet-stream] | |