Re: [PATCH] clk: mediatek: Fix all warnings for missing struct clk_onecell_data

From: Sean Wang
Date: Sat Dec 23 2017 - 10:47:48 EST


On Sat, 2017-12-23 at 12:20 +0100, Jean Delvare wrote:
> Hi Sean,
>
> On Sat, 23 Dec 2017 15:56:36 +0800, sean.wang@xxxxxxxxxxxx wrote:
> > From: Sean Wang <sean.wang@xxxxxxxxxxxx>
> >
> > In fact, the clk-mtk.h header is unnecessary for reset.c and thus it's
> > safe to remove it from the file to get rid of below build warnings.
> >
> > All warnings (new ones prefixed by >>):
> >
> > In file included from drivers/clk/mediatek/reset.c:22:0:
> > >>drivers/clk/mediatek/clk-mtk.h:44:19: warning: 'struct clk_onecell_data'
> > declared inside parameter list will not be visible outside of
> > this definition or declaration
> > int num, struct clk_onecell_data *clk_data);
> > ^~~~~~~~~~~~~~~~
> > drivers/clk/mediatek/clk-mtk.h:63:19: warning: 'struct clk_onecell_data'
> > declared inside parameter list will not be visible outside of
> > this definition or declaration
> > int num, struct clk_onecell_data *clk_data);
> > ^~~~~~~~~~~~~~~~
> > drivers/clk/mediatek/clk-mtk.h:145:10: warning: 'struct clk_onecell_data'
> > declared inside parameter list will not be visible outside of
> > this definition or declaration
> > struct clk_onecell_data *clk_data);
> > ^~~~~~~~~~~~~~~~
> > drivers/clk/mediatek/clk-mtk.h:164:11: warning: 'struct clk_onecell_data'
> > declared inside parameter list will not be visible outside of
> > this definition or declaration
> > struct clk_onecell_data *clk_data);
> > ^~~~~~~~~~~~~~~~
> > drivers/clk/mediatek/clk-mtk.h:190:12: warning: 'struct clk_onecell_data'
> > declared inside parameter list will not be visible outside of this
> > definition or declaration
> > struct clk_onecell_data *clk_data);
> > ^~~~~~~~~~~~~~~~
>
> That's not the proper fix. The actual problem here is in clk-mtk.h,
> which declares functions which need struct clk_onecell_data without
> declaring that structure first. This can be fixed in 2 ways:
>
> 1* #Include whatever header file provides the definition of struct
> clk_onecell_data (I think <linux/clk-provider.h>) in clk-mtk.h
> itself.
>
> 2* As you only manipulate pointers and not the structure itself, you
> could simply declare that this struct exists, without defining it,
> prior to referencing it in clk-mtk.h. As easy as:
>
> struct clk_onecell_data;
>
> In this case option 1 seems preferable.
>
> The reason why the problem is only visible in reset.c is because other
> source files under drivers/clk/mediatek #include <linux/clk-provider.h>
> explicitly before #including clk-mtk.h. But it only works "by
> accident". Ideally header files should be self-sufficient, so you don't
> depend on #include order.
>

agreed on above. I also prefer using option 1 to solve original issue.

> > Reported-by: kbuild test robot <fengguang.wu@xxxxxxxxx>
> > Signed-off-by: Sean Wang <sean.wang@xxxxxxxxxxxx>
> > Cc: kbuild-all@xxxxxx
> > Cc: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
> > Cc: linux-clk@xxxxxxxxxxxxxxx
> > ---
> > drivers/clk/mediatek/reset.c | 2 --
> > 1 file changed, 2 deletions(-)
> >
> > diff --git a/drivers/clk/mediatek/reset.c b/drivers/clk/mediatek/reset.c
> > index d3551d5..70ebb2e 100644
> > --- a/drivers/clk/mediatek/reset.c
> > +++ b/drivers/clk/mediatek/reset.c
> > @@ -19,8 +19,6 @@
> > #include <linux/reset-controller.h>
> > #include <linux/slab.h>
> >
> > -#include "clk-mtk.h"
> > -
> > struct mtk_reset {
> > struct regmap *regmap;
> > int regofs;
>
> If the header file is indeed not needed then that's still a good
> change, even if it doesn't fix the problem, so:
>
> Reviewed-by: Jean Delvare <jdelvare@xxxxxxx>

> However the patch description should be adjusted accordingly.


I will use another patch to remove the indeed not needed header

thanks a lot for your detailed explanation and help

Sean