Re: [arm:zii 20/80] drivers/net/dsa/xrs700x/xrs700x.c:714:37: warning: 'xrs700x_phylink_mac_ops' defined but not used

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Thu, Apr 18, 2024 at 09:20:42AM +0100, Russell King (Oracle) wrote:
> On Thu, Apr 18, 2024 at 06:26:42AM +0800, kernel test robot wrote:
> > All warnings (new ones prefixed by >>):
> > 
> > >> drivers/net/dsa/xrs700x/xrs700x.c:714:37: warning: 'xrs700x_phylink_mac_ops' defined but not used [-Wunused-const-variable=]
> >      714 | static const struct phylink_mac_ops xrs700x_phylink_mac_ops = {
> >          |                                     ^~~~~~~~~~~~~~~~~~~~~~~
> 
> My testing did not produce this warning, so I'm guessing that by default
> the kernel does not build with this warning enabled - which seems to be
> completely mad. This is not the first time that this has happened... and
> it will not be the last while the kernel adopts this policy.
> 
> Your follow-up email shows that there are other warnings which will be
> spat out with W=1 which will make spotting one new warning difficult,
> so this isn't the answer either.
> 
> I guess we are now completely reliant on the 0-day robot finding these
> cases... which sucks.

Double-checking, yes, the build is clean and does not spit out the above
warning. However, building with W=1 spits out around 5.3k of warnings,
so needle in a haystack, especially for a subsystem maintainer who may
have to touch a lot of drivers (like I'm doing.)

I guess we just have to accept that mistakes will happen, and there's
no good way to do a build-test to pick up on this kind of issue, and
just generate fixes as and when the 0-day kernel builder finds them.

-- 
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