RE: [PATCH V3 02/10] init.h: Fix the __setup_param() macro for module build

[Anson Huang <anson.huang@nxp.com>]

Hi, Arnd


> Subject: Re: [PATCH V3 02/10] init.h: Fix the __setup_param() macro for
> module build
> 
> On Mon, Jun 29, 2020 at 1:40 PM Anson Huang <anson.huang@nxp.com>
> wrote:
> > > Subject: Re: [PATCH V3 02/10] init.h: Fix the __setup_param() macro
> > > for module build
> > >
> > > On Mon, Jun 29, 2020 at 8:06 AM Anson Huang <Anson.Huang@nxp.com>
> > > wrote:
> > > >
> > > > Keep __setup_param() to use same parameters for both built in and
> > > > built as module, it can make the drivers which call it easier when
> > > > the drivers can be built in or built as module.
> > > >
> > > > Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> > >
> > > I wonder if we should instead drop the __setup() and __setup_param()
> > > definitions from the #else block here. This was clearly not used
> > > anywhere, and it sounds like any possible user is broken and should
> > > be changed to not use
> > > __setup() anyway.
> > >
> >
> >
> > It makes sense to drop the __setup() and __serup_param() in the #else
> > block, just use one definition for all cases, if no one objects, I will remove
> them in next patch series.
> 
> Ok, sounds good. Note that there may be users of the plain __setup() that just
> get turned into nops right now. Usually those are already enclosed in "#ifndef
> MODULE", but if they are not, then removing the definition would cause a
> build error.
> 
> Have a look if you can find such instances, and either change the patch to add
> the missing "#ifndef MODULE" checks, or just drop the __setup_param() and
> leave the __setup() if it gets too complicated.

Looks like the __setup_param() defined in "#ifndef MODULE" can NOT be used for 
MODULE build at all, so sharing same implementation is NOT available, so if it is NOT
that critical, I plan to keep the #else block in this patch, let me know if you have further
concern or any other suggestion, below is the build error reported for module build using
__setup_param() implementation for built in.

thanks,
Anson


In file included from ./arch/arm64/include/asm/alternative.h:12,
                 from ./arch/arm64/include/asm/lse.h:15,
                 from ./arch/arm64/include/asm/cmpxchg.h:14,
                 from ./arch/arm64/include/asm/atomic.h:16,
                 from ./include/linux/atomic.h:7,
                 from ./include/asm-generic/bitops/atomic.h:5,
                 from ./arch/arm64/include/asm/bitops.h:26,
                 from ./include/linux/bitops.h:29,
                 from ./include/linux/kernel.h:12,
                 from ./include/linux/clk.h:13,
                 from drivers/clk/imx/clk.c:2:
./include/linux/init.h:177:16: error: variable ‘__setup_imx_keep_uart_earlycon’ has initializer but incomplete type
  177 |  static struct obs_kernel_param __setup_##unique_id  \
      |                ^~~~~~~~~~~~~~~~
drivers/clk/imx/clk.c:157:1: note: in expansion of macro ‘__setup_param’
  157 | __setup_param("earlycon", imx_keep_uart_earlycon,
      | ^~~~~~~~~~~~~
./include/linux/init.h:180:7: warning: excess elements in struct initializer
  180 |   = { __setup_str_##unique_id, fn, early }
      |       ^~~~~~~~~~~~
drivers/clk/imx/clk.c:157:1: note: in expansion of macro ‘__setup_param’
  157 | __setup_param("earlycon", imx_keep_uart_earlycon,
      | ^~~~~~~~~~~~~
./include/linux/init.h:180:7: note: (near initialization for ‘__setup_imx_keep_uart_earlycon’)
  180 |   = { __setup_str_##unique_id, fn, early }
      |       ^~~~~~~~~~~~
drivers/clk/imx/clk.c:157:1: note: in expansion of macro ‘__setup_param’
  157 | __setup_param("earlycon", imx_keep_uart_earlycon,
      | ^~~~~~~~~~~~~
drivers/clk/imx/clk.c:158:8: warning: excess elements in struct initializer
  158 |        imx_keep_uart_clocks_param, 0);
      |        ^~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/init.h:180:32: note: in definition of macro ‘__setup_param’
  180 |   = { __setup_str_##unique_id, fn, early }
      |                                ^~
drivers/clk/imx/clk.c:158:8: note: (near initialization for ‘__setup_imx_keep_uart_earlycon’)
  158 |        imx_keep_uart_clocks_param, 0);
      |        ^~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/init.h:180:32: note: in definition of macro ‘__setup_param’
  180 |   = { __setup_str_##unique_id, fn, early }
      |                                ^~
drivers/clk/imx/clk.c:158:36: warning: excess elements in struct initializer
  158 |        imx_keep_uart_clocks_param, 0);
      |                                    ^
./include/linux/init.h:180:36: note: in definition of macro ‘__setup_param’
  180 |   = { __setup_str_##unique_id, fn, early }
      |                                    ^~~~~
drivers/clk/imx/clk.c:158:36: note: (near initialization for ‘__setup_imx_keep_uart_earlycon’)
  158 |        imx_keep_uart_clocks_param, 0);
      |                                    ^
./include/linux/init.h:180:36: note: in definition of macro ‘__setup_param’
  180 |   = { __setup_str_##unique_id, fn, early }
      |                                    ^~~~~
./include/linux/init.h:177:16: error: variable ‘__setup_imx_keep_uart_earlyprintk’ has initializer but incomplete type
  177 |  static struct obs_kernel_param __setup_##unique_id  \
      |                ^~~~~~~~~~~~~~~~
drivers/clk/imx/clk.c:159:1: note: in expansion of macro ‘__setup_param’
  159 | __setup_param("earlyprintk", imx_keep_uart_earlyprintk,
      | ^~~~~~~~~~~~~
./include/linux/init.h:180:7: warning: excess elements in struct initializer
  180 |   = { __setup_str_##unique_id, fn, early }
      |       ^~~~~~~~~~~~
drivers/clk/imx/clk.c:159:1: note: in expansion of macro ‘__setup_param’
  159 | __setup_param("earlyprintk", imx_keep_uart_earlyprintk,
      | ^~~~~~~~~~~~~
./include/linux/init.h:180:7: note: (near initialization for ‘__setup_imx_keep_uart_earlyprintk’)
  180 |   = { __setup_str_##unique_id, fn, early }
      |       ^~~~~~~~~~~~
drivers/clk/imx/clk.c:159:1: note: in expansion of macro ‘__setup_param’
  159 | __setup_param("earlyprintk", imx_keep_uart_earlyprintk,
      | ^~~~~~~~~~~~~
drivers/clk/imx/clk.c:160:8: warning: excess elements in struct initializer
  160 |        imx_keep_uart_clocks_param, 0);
      |        ^~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/init.h:180:32: note: in definition of macro ‘__setup_param’
  180 |   = { __setup_str_##unique_id, fn, early }
      |                                ^~
drivers/clk/imx/clk.c:160:8: note: (near initialization for ‘__setup_imx_keep_uart_earlyprintk’)
  160 |        imx_keep_uart_clocks_param, 0);
      |        ^~~~~~~~~~~~~~~~~~~~~~~~~~
./include/linux/init.h:180:32: note: in definition of macro ‘__setup_param’
  180 |   = { __setup_str_##unique_id, fn, early }
      |                                ^~
drivers/clk/imx/clk.c:160:36: warning: excess elements in struct initializer
  160 |        imx_keep_uart_clocks_param, 0);
      |                                    ^
./include/linux/init.h:180:36: note: in definition of macro ‘__setup_param’
  180 |   = { __setup_str_##unique_id, fn, early }
      |                                    ^~~~~
drivers/clk/imx/clk.c:160:36: note: (near initialization for ‘__setup_imx_keep_uart_earlyprintk’)
  160 |        imx_keep_uart_clocks_param, 0);
      |                                    ^
./include/linux/init.h:180:36: note: in definition of macro ‘__setup_param’
  180 |   = { __setup_str_##unique_id, fn, early }
      |                                    ^~~~~
./include/linux/init.h:177:33: error: storage size of ‘__setup_imx_keep_uart_earlycon’ isn’t known
  177 |  static struct obs_kernel_param __setup_##unique_id  \
      |                                 ^~~~~~~~
drivers/clk/imx/clk.c:157:1: note: in expansion of macro ‘__setup_param’
  157 | __setup_param("earlycon", imx_keep_uart_earlycon,
      | ^~~~~~~~~~~~~
./include/linux/init.h:177:33: error: storage size of ‘__setup_imx_keep_uart_earlyprintk’ isn’t known
  177 |  static struct obs_kernel_param __setup_##unique_id  \
      |                                 ^~~~~~~~
drivers/clk/imx/clk.c:159:1: note: in expansion of macro ‘__setup_param’
  159 | __setup_param("earlyprintk", imx_keep_uart_earlyprintk,
      | ^~~~~~~~~~~~~
scripts/Makefile.build:280: recipe for target 'drivers/clk/imx/clk.o' failed

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