linux-kernel - Re: [PATCH] clk: qcom: ipq4019: fix apss cpu overclocking

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Date:   Mon, 8 Jun 2020 11:43:16 +0200
From:   Robert Marko <robert.marko@...tura.hr>
To:     Nathan Chancellor <natechancellor@...il.com>
Cc:     kernel test robot <lkp@...el.com>, Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Michael Turquette <mturquette@...libre.com>, sboyd@...nel.org,
        Abhishek Sahu <absahu@...eaurora.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
        kbuild-all@...ts.01.org, clang-built-linux@...glegroups.com,
        Christian Lamparter <chunkeey@...il.com>,
        John Crispin <john@...ozen.org>
Subject: Re: [PATCH] clk: qcom: ipq4019: fix apss cpu overclocking

On Mon, Jun 8, 2020 at 11:07 AM Nathan Chancellor
<natechancellor@...il.com> wrote:
>
> On Mon, Jun 08, 2020 at 10:54:34AM +0200, Robert Marko wrote:
> > On Thu, Jun 4, 2020 at 10:25 PM kernel test robot <lkp@...el.com> wrote:
> > >
> > > Hi Robert,
> > >
> > > I love your patch! Perhaps something to improve:
> > >
> > > [auto build test WARNING on clk/clk-next]
> > > [also build test WARNING on v5.7 next-20200604]
> > > [if your patch is applied to the wrong git tree, please drop us a note to help
> > > improve the system. BTW, we also suggest to use '--base' option to specify the
> > > base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
> > >
> > > url:    https://github.com/0day-ci/linux/commits/Robert-Marko/clk-qcom-ipq4019-fix-apss-cpu-overclocking/20200605-002859
> > > base:   https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git clk-next
> > > config: x86_64-allyesconfig (attached as .config)
> > > compiler: clang version 11.0.0 (https://github.com/llvm/llvm-project ac47588bc4ff5927a01ed6fcd269ce86aba52a7c)
> > > reproduce (this is a W=1 build):
> > >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> > >         chmod +x ~/bin/make.cross
> > >         # install x86_64 cross compiling tool for clang build
> > >         # apt-get install binutils-x86-64-linux-gnu
> > >         # save the attached .config to linux build tree
> > >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64
> > >
> > > If you fix the issue, kindly add following tag as appropriate
> > > Reported-by: kernel test robot <lkp@...el.com>
> > >
> > > All warnings (new ones prefixed by >>, old ones prefixed by <<):
> > >
> > > >> drivers/clk/qcom/gcc-ipq4019.c:1247:24: warning: no previous prototype for function 'qcom_find_freq_close' [-Wmissing-prototypes]
> > > const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
> > > ^
> > > drivers/clk/qcom/gcc-ipq4019.c:1247:7: note: declare 'static' if the function is not intended to be used outside of this translation unit
> > > const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
> > > ^
> > > static
> > > 1 warning generated.
> > >
> > > vim +/qcom_find_freq_close +1247 drivers/clk/qcom/gcc-ipq4019.c
> > >
> > >   1245
> > >   1246
> > > > 1247  const struct freq_tbl *qcom_find_freq_close(const struct freq_tbl *f,
> > >   1248                                               unsigned long rate)
> > >   1249  {
> > >   1250          const struct freq_tbl *last = NULL;
> > >   1251
> > >   1252          for ( ; f->freq; f++) {
> > >   1253                  if (rate == f->freq)
> > >   1254                          return f;
> > >   1255
> > >   1256                  if (f->freq > rate) {
> > >   1257                          if (!last ||
> > >   1258                             (f->freq - rate) < (rate - last->freq))
> > >   1259                                  return f;
> > >   1260                          else
> > >   1261                                  return last;
> > >   1262                  }
> > >   1263                  last = f;
> > >   1264          }
> > >   1265
> > >   1266          return last;
> > >   1267  }
> > >   1268
> > >
> > > ---
> > > 0-DAY CI Kernel Test Service, Intel Corporation
> > > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
> >
>
> <moved post to the bottom>
>
> > Sorry for asking, but are these warnings relevant?
> > GCC9.3 does not throw them
> >
> > Regards
> > Robert
> >
>
> It should if you are using make W=1, this is not a clang specific
> warning (it just happens that clang was the compiler for this report).

Thanks, W=1 does indeed show the warning along with a not evaluated return.
>
> It looks like qcom_find_freq_close is only used in
> drivers/clk/qcom/gcc-ipq4019.c, in which case it should be marked
> static.
Thanks, it does indeed solve the warning.
I will send a v2 today.

Regards,
Robert
>
> Cheers,
> Nathan