Re: [PATCH v2] mmc: mmci_qcom_dml: include mmci_qcom_dml.h and fix #ifdef

From: Masahiro Yamada
Date: Sat Aug 05 2017 - 23:02:48 EST

Hi Arnd,

2017-08-05 7:10 GMT+09:00 Arnd Bergmann <arnd@xxxxxxxx>:
> On Fri, Aug 4, 2017 at 3:34 PM, Masahiro Yamada
> <yamada.masahiro@xxxxxxxxxxxxx> wrote:
>> Include mmci_qcom_dml.h from mmci_qcom_dml.c to fix the following
>> sparse warnings:
>> CHECK drivers/mmc/host/mmci_qcom_dml.c
>> drivers/mmc/host/mmci_qcom_dml.c:57:6: warning: symbol 'dml_start_xfer' was not declared. Should it be static?
>> drivers/mmc/host/mmci_qcom_dml.c:122:5: warning: symbol 'dml_hw_init' was not declared. Should it be static?
>> Fixing them causes redefintion of dml_start_xfer error, revealing another
>> problem in the header. #ifdef CONFIG_MMC_QCOM_DML is wrong because this
>> driver is tristate. (CONFIG_MMC_QCOM_DML_MODULE is defined when it is
>> built as a module)
>> Since dml_hw_init() is called from mmci.c, IS_REACHABLE() is needed to
>> cater to all the combinations.
>> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
> I think this is still not a good solution, it will just turn a link error into
> an unusable system at runtime when the DML code is a loadable module
> but not used. Also, the symbols are not exported, so it won't work when both
> are built as modules.
> How about linking the DML code into the mmci module and making that
> Kconfig option a 'bool'?

You are right.
My patch does not solve the root of the problem.

It turned out not so trivial as I had first expected.

I'd like somebody else to take care of it
because I am not familiar with this driver.

(My first motivation was clean-up sparse reports,
and I thought it was easy to fix it, but it was not.)

Best Regards
Masahiro Yamada