On Wed, Sep 9, 2020 at 10:40 AM Greg Kroah-Hartman <gre...@linuxfoundation.org> wrote: > On Wed, Sep 09, 2020 at 09:08:14AM +0200, Krzysztof Kozlowski wrote: > > On Wed, 9 Sep 2020 at 09:02, Greg Kroah-Hartman > > <gre...@linuxfoundation.org> wrote: > > > On Wed, Sep 09, 2020 at 08:29:25AM +0200, Krzysztof Kozlowski wrote: > > > > On Wed, 26 Aug 2020 at 18:18, Joe Perches <j...@perches.com> wrote: > > > > > On Wed, 2020-08-26 at 18:55 +0300, Andy Shevchenko wrote: > > > > > > On Wed, Aug 26, 2020 at 08:44:30AM -0700, Joe Perches wrote: > > > > > > > On Wed, 2020-08-26 at 13:44 +0300, Andy Shevchenko wrote: > > > > > > > > > > > > ... > > > > > > > > > > > > > > -int dev_err_probe(const struct device *dev, int err, const > > > > > > > > char *fmt, ...); > > > > > > > > +int __must_check dev_err_probe(const struct device *dev, int > > > > > > > > err, const char *fmt, ...); > > > > > > > > +Cc Stephen and Greg, > > > > > > > > Hi Andy, > > > > > > > > Did this patch ended up in next somehow? I am surprised because now I > > > > got warnings for perfectly fine code: > > > > https://lore.kernel.org/linux-next/20200909155654.76fe3...@canb.auug.org.au/T/#u > > > > > > > > This creates simply false warnings instead of hints for "optimization". > > > > > > Yes, it got merged into m y driver core tree. > > > > > > I'll fix up the tty build warning, should be easy enough, the patch is > > > below. > > > > Yes, this fix suppresses the warning but the question is whether we > > really want the warning? > > Such fixes mean additional code which the compiler might not optimize > > (unless it inlines the dev_err_probe()). This additional code is > > purely for suppressing the warning, without any meaning on its own. > > Actually it might be even confusing for someone to see: > > if (ret) > > ret = dev_err_probe(ret);
The problem here is that the dev_err_probe() returns int on purpose. In your patch what I can see it seems another issue is that the driver is semi converted to devm API and thus uses goto:s here and there. > Yeah, that is dumb, as the patch I made shows :( I agree. > > warn_unused_result should point errors, not "optimization > > opportunities". If you want to have opportunity, add a coccinelle > > rule. Or a checkpatch rule. Not a compiler warning. > > Ok, I now agree, I'll go revert this patch and trust that driver authors > will "do the right thing" here... I'm fine (as I stated during a review of that patch) to go either way, but I see it would be nice to have drivers be better thought about using devm APIs. -- With Best Regards, Andy Shevchenko