Re: [PATCH] iomap: hide iomap_sector with CONFIG_BLOCK=n

[Randy Dunlap]

On 7/18/19 7:19 PM, Masahiro Yamada wrote:
> Hi.
> 
> On Thu, Jul 18, 2019 at 11:28 PM Darrick J. Wong
> <darrick.wong@xxxxxxxxxx> wrote:
>>
>> On Thu, Jul 18, 2019 at 03:08:35PM +0200, Christoph Hellwig wrote:
>>> On Thu, Jul 18, 2019 at 03:03:15PM +0200, Arnd Bergmann wrote:
>>>> The inclusion comes from the recently added header check in commit
>>>> c93a0368aaa2 ("kbuild: do not create wrappers for header-test-y").
>>>>
>>>> This just tries to include every header by itself to see if there are build
>>>> failures from missing indirect includes. We probably don't want to
>>>> add an exception for iomap.h there.
>>>
>>> I very much disagree with that check.  We don't need to make every
>>> header compilable with a setup where it should not be included.
>>
>> Seconded, unless there's some scenario where someone needs iomap when
>> CONFIG_BLOCK=n (???)
> 
> I agree.
> 
> There is no situation that iomap.h is included when CONFIG_BLOCK=n.
> So, it is pointless to surround offending code with #ifdef
> just for the purpose of satisfying the header-test.
> 
> 
> I started to think
> compiling all headers is more painful than useful.
> 
> 
> MW is closing, so I am thinking of disabling it for now
> to take time to re-think.
> 
> 
> diff --git a/init/Kconfig b/init/Kconfig
> index bd7d650d4a99..cbb31d134f7e 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -111,6 +111,7 @@ config HEADER_TEST
>  config KERNEL_HEADER_TEST
>         bool "Compile test kernel headers"
>         depends on HEADER_TEST
> +       depends on BROKEN
>         help
>           Headers in include/ are used to build external moduls.
>           Compile test them to ensure they are self-contained, i.e.
> 
> 
> 
> Maybe, we should compile-test headers
> only when it is reasonable to do so.

Maybe.  But I would find it easier to use if it were a make target
instead of a Kconfig symbol, so someone could do
$ make compile_test_headers

for example.  Then it would be done only on demand (or command).

-- 
~Randy