Messages in this thread | | | Date | Wed, 9 Sep 2020 09:37:16 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH v1] driver core: Annotate dev_err_probe() with __must_check |
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On Wed, Sep 09, 2020 at 09:08:14AM +0200, Krzysztof Kozlowski wrote: > On Wed, 9 Sep 2020 at 09:02, Greg Kroah-Hartman > <gregkh@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 <joe@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/20200909155654.76fe3bd6@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);
Yeah, that is dumb, as the patch I made shows :(
> 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...
thanks,
greg k-h
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